the Draco constellation

Draco is a constellation in the far northern sky.

Draco is a constellation in the far northern sky. Its name is Latin for dragon. Draco is circumpolar (that is, never setting) for many observers in the northern hemisphere. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations today. The north pole of the ecliptic is in Draco. Draco can be seen all year.

The constellation of draco

 

Thuban (a Draconis) was the northern pole star from 3942 BC, when it moved farther north than Theta Boötis, until 1793 BC. The Egyptian Pyramids were designed to have one side facing north, with an entrance passage designed so that Thuban would be visible at night. Due to the effects of precession, it will once again be the pole star around the year 21000 AD. It is a blue-white giant star of magnitude 3.7, 309 light-years from Earth. The traditional name of Alpha Draconis, Thuban, means “head of the serpent”.
There are two other stars above magnitude 3 in Draco. The brighter of the two—and the brightest star in Draco—is Gamma Draconis, traditionally called Etamin or Eltanin. It is an orange giant star of magnitude 2.2, 148 light-years from Earth. The aberration of starlight was discovered in 1728 when James Bradley observed Gamma Draconis. Beta Draconis, traditionally called Rastaban, is a yellow giant star of magnitude 2.8, 362 light-years from Earth. Its name shares a meaning with Thuban, “head of the serpent”.

Draco is home to several double stars and binary stars.  Draconis is a double star with a yellow-hued primary of magnitude 2.8 and a white-hued secondary of magnitude 8.2 located south of the primary. The two are separated by 4.8 arcseconds. Mu Draconis, traditionally called Alrakis, is a binary star with two white components. Magnitude 5.6 and 5.7, the two components orbit each other every 670 years. The Alrakis system is 88 light-years from Earth. Nu Draconis is a similar binary star with two white components, 100 light-years from Earth. Both components are of magnitude 4.9 and can be distinguished in a small amateur telescope or a pair of binoculars. Omicron Draconis is a double star divisible in small telescopes. The primary is an orange giant of magnitude 4.6, 322 light-years from Earth.

The secondary is of magnitude 7.8. Psi Draconis is a binary star divisible in binoculars and small amateur telescopes, 72 light-years from Earth. The primary is a yellow-white star

of magnitude 4.6 and the secondary is a yellow star of magnitude 5.8. 16 Draconis and 17 Draconis are part of a triple star 400 light-years from Earth, divisible in medium-sized

amateur telescopes. The primary, a blue-white star of magnitude 5.1, is itself a binary with components of magnitude 5.4 and 6.5. The secondary is of magnitude 5.5 and the

system is 400 light-years away. 20 Draconis is a binary star with a white-hued primary of magnitude 7.1 and a yellow-hued secondary of magnitude 7.3 located east-northeast of the

primary. The two are separated by 1.2 arc seconds at their maximum and have an orbital period of 420 years. As of 2012, the two components are approaching their maximum

separation. 39 Draconis is a triple star 188 light-years from Earth, divisible in small amateur telescopes. The primary is a blue star of magnitude 5.0, the secondary is a yellow star of magnitude 7.4, and the tertiary is a star of magnitude 8.0; the tertiary appears to be a close companion to the primary. 40 Draconis and 41 Draconis are a binary star divisible in small telescopes. The two orange dwarf stars are 170 light-years from Earth and are of magnitude 5.7 and 6.1.

R Draconis is a red Mira-type variable star with a period of about 8 months. Its average minimum magnitude is approximately 12.4, and its average maximum magnitude is approximately 7.6. It was discovered to be a variable star by Hans Geelmuyden in 1876.
The constellation contains the star recently named Kepler-10 which has been confirmed to be orbited by Kepler-10b, the smallest ever rocky Earth-sized planet detected outside of our solar system.

The Deep-sky Objects in Draco

One of the deep-sky objects in Draco is the Cat’s Eye Nebula (NGC 6543), a planetary nebula approximately 3,000 light-years away that was discovered by English astronomer William Herschel in 1786. It is 9th magnitude and was named for its appearance in the Hubble Space Telescope, though it appears as a fuzzy blue-green disk in an amateur telescope.NGC 6543 has a very complex shape due to gravitational interactions between the components of the multiple star at its center, the progenitor of the nebula approximately 1,000 years ago. It is located 9.6 arcminutes away from the north ecliptic pole to the west-northwest. It is also related to IC 4677, a nebula that appears as a bar 1.8 arcminutes to the west of the Cat’s Eye nebula. In long-term exposures, IC 4677 appears as a portion of a ring surrounding the planetary nebula.

There are several faint galaxies in Draco, one of which is the lenticular galaxy NGC 5866, sometimes considered to be Messier Object 102. Another is the Draco Dwarf Galaxy, one of the least luminous galaxies with an absolute magnitude of -8.6 and a diameter of only about 3,500 light years, discovered by Albert G. Wilson of Lowell Observatory in 1954.

Another dwarf galaxy found in this constellation is PGC 39058.
Draco also features several interacting galaxies and galaxy clusters. One such massive cluster is Abell 2218, located at a distance of 3 billion light-years (redshift 0.171). It acts as a gravitational lens for even more distant background galaxies, allowing astronomers to study those galaxies as well as Abell 2218 itself; more specifically, the lensing effect allows

astronomers to confirm the cluster’s mass as determined by x-ray emissions. One of the most well-known interacting galaxies is Arp 188, also called the “Tadpole Galaxy”.
Named for its appearance, which features a “tail” of stars 280,000 light-years long, the Tadpole Galaxy is at a distance of 420 million light-years (redshift 0.0314). The tail of stars drawn off the Tadpole Galaxy appears blue because the gravitational interaction disturbed clouds of gas and sparked star formation.

Q1634+706 is a quasar that holds the distinction of being the most distant object usually visible in an amateur telescope. At magnitude 14.4, it appears starlike, though it is at a distance of 12.9 billion light-years. The light of Q1634+706 has taken 8.6 billion years to reach Earth, a discrepancy attributable to the expansion of the universe.

Draco Mythology

Dragons in Greek mythology that may have inspired the constellation’s name include Ladon, the dragon who guarded the golden apples of the Hesperides. Hercules killed Ladon during his 12 labors; he was tasked with stealing the golden apples. The constellation of Hercules is depicted near Draco.
In Greco- Roman legend, Draco was a dragon killed by the goddess Minerva and tossed into the sky upon his defeat. The dragon was one of the Gigantes, who battled the Olympic gods for ten years. As Minerva threw the dragon, it became twisted on itself and froze at the cold North Celestial Pole before it could right itself. Sometimes, Draco is represented as the demon son of Gaia, Typhon.

 

Mythical Image of Draco
Mythical Draco

Traditional Arabic astronomy does not depict a dragon in modern-day Draco, which is called the Mother Camels. Instead, two hyenas, represented by Eta Draconis and Zeta Draconis are seen attacking a baby camel (a dim star near Beta Draconis), which is protected by four female camels, represented by Beta Draconis, Gamma Draconis, Nu Draconis, and Xi Draconis. The nomads who own the camels are camped nearby, represented by a cooking tripod composed of Upsilon, Tau, and Sigma Draconis.

 

In some mythology, Draco the dragon constellation had one- hundred magnificent heads, and gourded the golden apple tree, and put in the sky as a constellation for his bravery at protecting the apples. There are more myths than that, but that is one of the most common ones.

Lacerta Constellation

Lacerta 2014-10-16 01.22.08
Lacerta 2014-10-16 01.22.08
Lacerta in skymap

Not easy to see with the naked eye

Lacerta is one of the 88 modern constellations defined by the International Astronomical Union. Its name is Latin for lizard. A small, faint constellation, it was created in 1687 by the astronomer Johannes Hevelius. Its brightest stars form a “W” shape similar to that of Cassiopeia, and it is thus sometimes referred to as ‘Little Cassiopeia’. It is located between Cygnus, Cassiopeia and Andromeda on the northern celestial sphere. The northern part lies on the Milky Way.

Stars in Lacerta

Alpha Lacertae is a blue-white hued main-sequence star of magnitude 3.8, 102 light-years from Earth. It has a spectral type of A1 V and is an optical double star. Beta Lacertae is far dimmer, a yellow giant of magnitude 4.4, 170 light-years from Earth.

Roe 47 is a multiple star consisting of five components (magnitudes 5.8, 9.8, 10.1, 9.4, 9.8).

ADS 16402 is a binary star system in Lacerta, around which a planet orbits with some unusual properties. The Jupiter-sized planet exhibits an unexpectedly low density, about the same as cork. This planet is dubbed HAT P-1.

EV Lacertae is a rapidly spinning magnitude 10 red dwarf with a strong magnetic field. It is a flare star that can emit powerful flares potentially visible to the naked eye, thousands of times more energetic than any from Earth’s sun.

Hot Jupiter’s – Basic Information

jups

Need to know what is meant by the term hot jupiters?

Hot Jupiters (also called roaster planets, epistellar jovians, pegasids or pegasean planets) are a class of extrasolar planets whose characteristics are similar to Jupiter, but that have high surface temperatures because they orbit very close—between approximately 0.015 and 0.5 astronomical units (2.2×10^6 and 74.8×10^6 km)—to their parent stars, whereas Jupiter orbits its parent star (the Sun) at 5.2 astronomical units (780×10^6 km), causing low surface temperatures.

One of the best-known hot Jupiters is 51 Pegasi b, nicknamed Bellerophon. Discovered in 1995, it was the first extrasolar planet found orbiting a Sun-like star. 51 Pegasi b has an orbital period of about 4 days.

jups hot

 

Hot Jupiters have some common characteristics:

  • They have similar characteristics to Jupiter (gas giants, usually with masses close to or exceeding that of Jupiter, which is 1.9×1027 kg), however, orbit much more closely to the star and experience a high surface temperature.
  • They have a much greater chance of transiting their star as seen from a farther outlying point than planets of the same mass in larger orbits. The most notable of these are HD 209458 b, the first transiting hot Jupiter found, HD 189733 b, which was first mapped in 2007 by the Spitzer Space Telescope, and HAT-P-7b, which was recently observed by the Kepler mission.
  • Due to high levels of insolation they are of a lower density than they would otherwise be. This has implications for radius determination, because due to limb darkening of the planet’s background star during a transit, the planet’s ingress and egress boundaries are harder to determine.
  • They are all thought to have migrated to their present positions because there would not have been enough material so close to the star for a planet of that mass to have formed in situ.
  • Most of these have nearly circular orbits (low eccentricities). This is because their orbits have been circularized, or are being circularized, by the process of libration.
  • They exhibit high-speed winds distributing the heat from the day side to the night side, thus the temperature difference between the two sides is relatively low.
  • They are more common around F- and G-type stars and somewhat less common around K-type stars. Hot Jupiters around red dwarfs are very rare.

Hot Jupiters are the easiest extrasolar planets to detect via the radial-velocity method, because the oscillations they induce in their parent stars’ motion are relatively large and rapid, compared to other known types of planets.

They are thought to form at a distance from the star beyond the frost line, where the planet can form from rock, ice and gases. The planets then migrate inwards to the star where they eventually form a stable orbit. The planets usually move by type 2 migrations, or possibly via interaction with other planets. The migration happens during the solar nebula phase, and will typically stop when the star enters its T-Tauri phase. The strong stellar winds at this time remove most of the remaining nebula.

After their atmospheres and outer layers are stripped away (hydrodynamic escape), their cores may become chthonian planets. The amount of the outermost layers that is lost depends on the size and the material of the planet and the distance from the star. In a typical system a gas giant orbiting 0.02 AU around its parent star loses 5–7% of its mass during its lifetime, but orbiting closer than 0.015 AU can mean evaporation of the whole planet except for its core.

Terrestrial planets in systems with hot Jupiters

Simulations have shown that the migration of a Jupiter-sized planet through the inner protoplanetary disk (the region between 5 and 0.1 AU from the star) is not as destructive as one might assume. More than 60% of the solid disk materials in that region are scattered outward, including planetesimals and protoplanets, allowing the planet-forming disk to reform in the gas giant’s wake. In the simulation, planets up to two Earth masses were able to form in the habitable zone after the hot Jupiter passed through and its orbit stabilized at 0.1 AU. Due to the mixing of inner-planetary-system material with outer-planetary-system material from beyond the frost line, simulations indicated that the terrestrial planets that formed after a hot Jupiter’s passage would be particularly water-rich.

Retrograde orbit

It has been found that several hot Jupiters have retrograde orbits and this calls into question the theories about the formation of planetary systems, although rather than a planet’s orbit having been disturbed, it may be that the star itself flipped over early in their system’s formation due to interactions between the star’s magnetic field and the planet-forming disc. By combining new observations with the old data it was found that more than half of all the hot Jupiters studied have orbits that are misaligned with the rotation axis of their parent stars, and six exoplanets in this study have retrograde motion.

 

Ultra-short-period Jupiters are a class of hot Jupiters with orbital periods below 1 day and occur only around stars of less than about 1.25 solar masses.

Five ultra-short-period planets have been identified in the region of the Milky Way known as the galactic bulge. They were observed by the Hubble Space Telescope and first described by researchers from the Space Telescope Science Institute, the Universidad Catolica de Chile, Uppsala University, the High Altitude Observatory, the INAF–Osservatorio Astronomico di Padova and the University of California at Los Angeles.

More transiting hot Jupiters have been discovered, such as WASP-18b and WASP-19b, that have orbital periods of less than one day that do not support the hypothesis of the research above.

 

 

The Niels Bohr Model

In 1911, Bohr travelled to England. At the time, it was where most of the theoretical work on the structure of atoms and molecules was being done. He met J. J. Thomson of the Cavendish Laboratory and Trinity College, Cambridge. He attended lectures on electromagnetism given by James Jeans and Joseph Larmor, and did some research on cathode rays, but failed to impress Thomson. He had more success with younger physicists like the Australian William Lawrence Bragg, and New Zealand’s Ernest Rutherford, whose 1911 Rutherford model of the atom had challenged Thomson’s 1904 plum pudding model.

Bohr received an invitation from Rutherford to conduct post-doctoral work
at Victoria University of Manchester, where Bohr met George de Hevesy and Charles Galton Darwin (whom Bohr referred to as “the grandson of the real Darwin”).
Bohr returned to Denmark in July 1912 for his wedding, and travelled around England and Scotland on his honeymoon. On his return, he became a privatdocent at the University of Copenhagen, giving lectures on thermodynamics. Martin Knudsen put Bohr’s name forward for a docent, which was approved in July 1913, and Bohr then began teaching medical students. His three papers, which later became famous as “the trilogy”, were published in Philosophical Magazine in July, September and November of that year. He adapted Rutherford’s nuclear structure to Max Planck’s quantum theory and so created his Bohr model of the atom.

Planetary models of atoms were not new, but Bohr’s treatment was. Taking the 1912 paper by Darwin on the role of electrons in the interaction of alpha particles with a nucleus as his starting point, he advanced the theory of electrons travelling in orbits around the atom’s nucleus, with the chemical properties of each element being largely determined by the number of electrons in the outer orbits of its atoms. He introduced the idea that an electron could drop from a higher-energy orbit to a lower one, in the process emitting a quantum of discrete energy. This became a basis for what is now known as the old quantum theory.

In atomic physics, the Rutherford–Bohr model or Bohr model, introduced by Niels Bohr in 1913, depicts the atom as a small, positively charged nucleus surrounded by electrons that travel in circular orbits around the nucleus—similar in structure to the solar system, but with attraction provided by electrostatic forces rather than gravity. After the cubic model (1902), the plum-pudding model (1904), the Saturnian model (1904), and the Rutherford model (1911) came the Rutherford–Bohr model or just Bohr model for short (1913). The improvement to the Rutherford model is mostly a quantum physical interpretation of it. The Bohr model has been superseded, but the quantum theory remains sound.

 

The model’s key success lay in explaining the Rydberg formula for the spectral emission lines of atomic hydrogen. While the Rydberg formula had been known experimentally, it did not gain a theoretical underpinning until the Bohr model was introduced. Not only did the Bohr model explain the reason for the structure of the Rydberg formula, it also provided a justification for its empirical results in terms of fundamental physical constants.

The Bohr model is a relatively primitive model of the hydrogen atom, compared to the valence shell atom. As a theory, it can be derived as a first-order approximation of the hydrogen atom using the broader and much more accurate quantum mechanics and thus may be considered to be an obsolete scientific theory. However, because of its simplicity, and its correct results for selected systems (see below for application), the Bohr model is still commonly taught to introduce students to quantum mechanics or energy level diagrams before moving on to the more accurate, but more complex, valence shell atom. A related model was originally proposed by Arthur Erich Haas in 1910, but was rejected. The quantum theory of the period between Planck’s discovery of the quantum (1900) and the advent of a full-blown quantum mechanics (1925) is often referred to as the old quantum theory.

 

Danish physicist Bohr

The Story of Niels Henrik David Bohr

Niels Bohr (7 October 1885 – 18 November 1962) was a Danish physicist who made foundational contributions to understanding atomic structure and quantum theory, for which he received the Nobel Prize in Physics in 1922. Bohr was also a philosopher and a promoter of scientific research.
Bohr developed the Bohr model of the atom, in which he proposed that energy levels of electrons are discrete and that the electrons revolve in stable orbits around the atomic nucleus but can jump from one energy level (or orbit) to another. Although the Bohr model has been supplanted by other models, its underlying principles remain valid. He conceived the principle of complementarity: that items could be separately analysed in terms of contradictory properties, like behaving as a wave or a stream of particles. The notion of complementarity dominated Bohr’s thinking in both science and philosophy.

Bohr founded the Institute of Theoretical Physics at the University of Copenhagen, now known as the Niels Bohr Institute, which opened in 1920. Bohr mentored and collaborated with physicists including Hans Kramers, Oskar Klein, George de Hevesy and Werner Heisenberg. He predicted the existence of a new zirconium-like element, which was named hafnium, after the Latin name for Copenhagen, where it was discovered. Later, the element bohrium was named after him.
During the 1930s, Bohr helped refugees from Nazism. After Denmark was occupied by the Germans, he had a famous meeting with Heisenberg, who had become the head of the German nuclear energy project. In September 1943, word reached Bohr that he was about to be arrested by the Germans, and he fled to Sweden. From there, he was flown to Britain, where he joined the British Tube Alloys nuclear weapons project, and was part of the British mission to the Manhattan Project. After the war, Bohr called for international cooperation on nuclear energy. He was involved with the establishment of CERN and the Research Establishment Risø of the Danish Atomic Energy Commission, and became the first chairman of the Nordic Institute for Theoretical Physics in 1957.

Early years

Niels Bohr was born in Copenhagen, Denmark, on 7 October 1885, the second of three children of Christian Bohr, a professor of physiology at the University of Copenhagen, and Ellen Adler Bohr, who came from a wealthy Danish Jewish family prominent in banking and parliamentary circles. He had an elder sister, Jenny, and a younger brother Harald. Jenny became a teacher, while Harald became a mathematician and Olympic footballer who played for the Danish national team at the 1908 Summer Olympics in London. Niels was a passionate footballer as well, and the two brothers played several matches for the Copenhagen-based Akademisk Boldklub, with Niels as goalkeeper.
Bohr was educated at Gammelholm Latin School, starting when he was seven. In 1903, Bohr enrolled as an undergraduate at Copenhagen University. His major was physics, which he studied under Professor Christian Christiansen, the university’s only professor of physics at that time. He also studied astronomy and mathematics under Professor Thorvald Thiele, and philosophy under Professor Harald Høffding, a friend of his father.

In 1905, a gold medal competition was sponsored by the Royal Danish Academy of Sciences and Letters to investigate a method for measuring the surface tension of liquids that had been proposed by Lord Rayleigh in 1879. This involved measuring the frequency of oscillation of the radius of a water jet. Bohr conducted a series of experiments using his father’s laboratory in the university; the university itself had no physics laboratory. To complete his experiments, he had to make his own glassware, creating test tubes with the required elliptical cross-sections. He went beyond the original task, incorporating improvements into both Rayleigh’s theory and his method, by taking into account the viscosity of the water, and by working with finite amplitudes instead of just infinitesimal ones. His essay, which he submitted at the last minute, won the prize. He later submitted an improved version of the paper to the Royal Society in London for publication in the Philosophical Transactions of the Royal Society.

Harald became the first of the two Bohr brothers to earn a master’s degree, which he earned for mathematics in April 1909. Niels took another nine months to earn his. Students had to submit a thesis on a subject assigned by their supervisor. Bohr’s supervisor was Christiansen, and the topic he chose was the electron theory of metals. Bohr subsequently elaborated his master’s thesis into his much larger Doctor of Philosophy (dr. phil.) thesis. He surveyed the literature on the subject, settling on a model postulated by Paul Drude and elaborated by Hendrik Lorentz, in which the electrons in a metal are considered to behave like a gas. Bohr extended Lorentz’s model but was still unable to account for phenomena like the Hall effect, and concluded that electron theory could not fully explain the magnetic properties of metals. The thesis was accepted in April 1911, and Bohr conducted his formal defence on 13 May. Harald had received his doctorate the previous year. Bohr’s thesis was ground breaking, but attracted little interest outside Scandinavia because it was written in Danish, a Copenhagen University requirement at the time. In 1921, the Dutch physicist Hendrika Johanna van Leeuwen would independently derive a theorem from Bohr’s thesis that is today known as the Bohr–van Leeuwen theorem.

 

 

Atomic orbital

Orbital Atom

An atomic orbital is a mathematical function that describes the wave-like behavior of either one electron or a pair of electrons in an atom. This function can be used to calculate the probability of finding any electron of an atom in any specific region around the atom’s nucleus. The term may also refer to the physical region or space where the electron can be calculated to be present, as defined by the particular mathematical form of the orbital.

Orbital black and white

Each orbital in an atom is characterized by a unique set of values of the three quantum numbers n, , and m, which correspond to the electron’s energy, angular momentum, and an angular momentum vector component, respectively. Any orbital can be occupied by a maximum of two electrons, each with its own spin quantum number. The simple names s orbital, p orbital, d orbital and f orbital refer to orbitals with angular momentum quantum number = 0, 1, 2 and 3 respectively. These names, together with the value of n, are used to describe the electron configurations. They are derived from the description by early spectroscopists of certain series of alkali metal spectroscopic lines as sharp, principal, diffuse, and fundamental. Orbitals for > 3 are named in alphabetical order (omitting j).

Atomic orbitals are the basic building blocks of the atomic orbital model (alternatively known as the electron cloud or wave mechanics model), a modern framework for visualizing the submicroscopic behavior of electrons in matter. In this model the electron cloud of a multi-electron atom may be seen as being built up (in approximation) in an electron configuration that is a product of simpler hydrogen-like atomic orbitals. The repeating periodicity of the blocks of 2, 6, 10, and 14 elements within sections of the periodic table arises naturally from the total number of electrons that occupy a complete set of s, p, d and f atomic orbitals, respectively.

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Emanuel Swedenborg

Emanuel Swedenborg born Emanuel Swedberg on 29 January 1688; died 29 March 1772) was a Swedish scientist, philosopher, theologian, revelator, and mystic. He is best known for his book on the afterlife, Heaven and Hell (1758).

Swedenborg had a prolific career as an inventor and scientist. In 1741, at age 53, he entered into a spiritual phase in which he began to experience dreams and visions, beginning on Easter weekend of April 6, 1744. This culminated in a ‘spiritual awakening’, in which he received revelation that he was appointed by the Lord to write The Heavenly Doctrine to reform Christianity. According to The Heavenly Doctrine the Lord had opened Swedenborg’s spiritual eyes, so that from then on he could freely visit heaven and hell and talk with angels, demons and other spirits; and the Last Judgment had already occurred, in 1757. However, he tells us that at this day it is very dangerous to talk with spirits, unless a person is in true faith, and is led by the Lord.

For the remaining 28 years of his life, Swedenborg wrote 18 published theological works, and several more which were unpublished. He termed himself a “Servant of the Lord Jesus Christ” in True Christian Religion, a work he published himself. Some followers of The Heavenly Doctrine believe that, of his theological works, only those which Swedenborg published himself are fully divinely inspired.

artist portrait of swedenborg
Swedenborg

 

Scientific period

In 1715 Swedenborg returned to Sweden, where he devoted himself to natural science and engineering projects for the next two decades. A first step was his meeting with King Charles XII of Sweden in the city of Lund, in 1716. The Swedish inventor Christopher Polhem, who became a close friend of Swedenborg, was also present. Swedenborg’s purpose was to persuade the king to fund an observatory in northern Sweden.

However, the warlike king did not consider this project important enough, but did appoint Swedenborg assessor-extraordinary on the Swedish Board of Mines (Bergskollegium) in Stockholm.

From 1716 to 1718, Swedenborg published a scientific periodical entitled Daedalus Hyperboreus (“The Northern Daedalus), a record of mechanical and mathematical inventions and discoveries. One notable description was that of a flying machine, the same he had been sketching a few years earlier (see Flying Machine (Swedenborg)).

In 1718 Swedenborg published an article that attempted to explain spiritual and mental events in terms of minute vibrations or “tremulations”.

Upon the death of Charles XII, Queen Ulrika Eleonora ennobled Swedenborg and his siblings. It was common in Sweden during the 17th and 18th centuries for the children of bishops to receive this honour as a recognition of the services of their father. The family name was changed from Swedberg to Swedenborg.

In 1724, he was offered the chair of mathematics at Uppsala University, but he declined and said that he had mainly dealt with geometry, chemistry and metallurgy during his career. He also said that he did not have the gift of eloquent speech because of a stutter, as recognized by many acquaintances of his; it forced him to speak slowly and carefully, and there are no known occurrences of his speaking in public. The Swedish critic Olof Lagerkrantz proposed that Swedenborg compensated for his impediment by extensive argumentation in writing.

AxialTiltObliquity

 

Orion Magnificent Sky View

September Orion Sight

I have just seen Orion for the first time with my naked eye, in 2014. A beautiful site creeping up behind a tree from my window view. The only bad part of that is – it means winter is on it’s way already!

The Orion constellation is in my opinion, by far the most glorious of all to see.

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The Eridanus Constellation

Eridanus is a large constellation represented as a river.

It’s name is the Ancient Greek name for the Po River. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and it remains one of the 88 modern constellations. It is the sixth largest of the modern constellations.

The Stars of Eridanis

At its southern end is the magnitude 0.5 star Achernar, designated Alpha Eridani. 144 light-years from Earth, it is a blue-white hued main sequence star whose traditional name means “the river’s end”. Achernar is a very peculiar star because it is one of the flattest stars known. Observations indicate that its radius is about 50% larger at the equator than at the poles. This distortion occurs because the star is spinning extremely rapidly.

There are several other noteworthy stars in Eridanus, including some double stars. Beta Eridani, traditionally called Cursa, is a blue-white star of magnitude 2.8, 89 light-years from Earth. Its place to the south of Orion’s foot gives it its name, which means “the footstool”. Theta Eridani, called Acamar, is a binary star with blue-white components, distinguishable in small amateur telescopes and 161 light-years from Earth.

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Me Eridanis

The primary is of magnitude 3.2 and the secondary is of magnitude 4.3. 32 Eridani is a binary star 290 light-years from Earth. The primary is a yellow-hued star of magnitude 4.8 and the secondary is a blue-green star of magnitude 6.1. 32 Eridani is divisible in small amateur telescopes. 39 Eridani is a binary star divisible in small amateur telescopes, 206 light-years from Earth. The primary is an orange-hued giant star of magnitude 4.9 and the secondary is of magnitude 8. 40 Eridani is a triple star system consisting of an orange main-sequence star, a white dwarf, and a red dwarf.

The orange main-sequence star is the primary of magnitude 4.4, and the white secondary of magnitude 9.5 is the most easily visible white dwarf. The red dwarf, of magnitude 11, orbits the white dwarf every 250 years. The 40 Eridani system is 16 light-years from Earth. p Eridani is a binary star with two orange components, 27 light-years from Earth. The magnitude 5.8 primary and 5.9 secondary have an orbital period of 500 years.
Epsilon Eridani is a star with one extrasolar planet similar to Jupiter. It is an orange-hued main-sequence star of magnitude 3.7, 10.5 light-years from Earth. Its one planet, with an approximate mass of one Jupiter mass, has a period of 7 years.

Deep-sky objects

NGC 1535 is a small blue-gray planetary nebula visible in small amateur telescopes, with a disk visible in large amateur instruments. 2000 light-years away, it is of the 9th magnitude.
Eridanus contains the galaxies NGC 1232, NGC 1234 and NGC 1300, a grand design barred spiral galaxy.
NGC 1300 is a face-on barred spiral galaxy located 61 (plus or minus 8) million light-years away. The center of the bar shows an unusual structure: within the overall spiral structure, a grand design spiral that is 3,300 light-years in diameter exists. Its spiral arms are tightly wound.

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Meteor showers

The Nu Eridanids, a recently discovered meteor shower, radiate from the constellation between August 30 and September 12 every year; the shower’s parent body is an unidentified Oort cloud object. Another meteor shower in Eridanus is the Omicron Eridanids, which peak between November 1 and 10.

 

 

Jan Hendrik Oort

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Astronomy Pioneer Jan Oort

portrait of jan oort
Jan Oort

Jan Oort (28 April 1900 – 5 November 1992) was a Dutch astronomer who made significant contributions to the understanding of the Milky Way and a pioneer in the field of radio astronomy. His New York Times obituary called him “one of the century’s foremost explorers of the universe;” the European Space Agency website describes him as, “one of the greatest astronomers of the 20th century,” and states that he “revolutionised astronomy through his ground-breaking discoveries.” In 1955, Oort’s name appeared in Life Magazine’s list of the 100 most famous living people. He has been described as “putting the Netherlands in the forefront of postwar astronomy.”

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Microscopium – Constellation

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It’s a Southern Sky Costellation – that can be seen  in the Northern Sky

It can be seen with the naked eye in the southern sky, low on the horizon – in the early hours of the morning in August.

Microscopium  is a small constellation in the southern sky, defined in the 18th century by Nicolas Louis de Lacaille. Its brightest star is Gamma Microscopii of apparent magnitude 4.68, actually a yellow giant located around 381 light-years distant. Two star systems—WASP-7 and HD 205739—have been found to have planets, while another—AU Microscopii—has a debris disk.

History

The stars that now comprise Microscopium may formerly have belonged to the hind feet of Sagittarius. However, this is uncertain as, while its stars seem to be referred to by Al-Sufi as having been seen by Ptolemy, Al-Sufi does not specify their exact positions.
Its name is Latin for microscope; it was invented by Lacaille to commemorate the compound microscope. Its stars are very faint and hardly visible from most of the non-tropical northern hemisphere.

Characteristics

The brightest star is Gamma Microscopii, which has an apparent (visual) magnitude of 4.68. It is a yellow giant of spectral type G6III. Lying 381 light years away, It depicts the eyepiece of the microscope. Alpha Microscopii is also a yellow giant, though in this case a variable star, which ranges between apparent magnitudes 4.88 and 4.94. It is of spectral type G7III. Alpha has a 10th magnitude companion, visible in small telescopes. Epsilon Microscopii lies 165 light years away, and is a blue-white main sequence star of apparent magnitude 4.7, and spectral type A1V. Theta1 and Theta2 Microscopii make up a wide double whose components are splittable to the naked eye. Both are white A-class magnetic spectrum variable stars with strong metallic lines, similar to Cor Caroli. They mark the constellation’s specimen slide.
Many notable objects are too faint to be seen with the naked eye. AX Microscopii, better known as Lacaille 8760, is a red dwarf which lies only 12.9 light years from our solar system. HD 205739 has a jupiter-sized planet. WASP-7 is a star of magnitude 9.54 which has been discovered to have an exoplanet WASP-7b, while AU Microscopii is a young star which appears to be a solar system in the making with a debris disk. BO Microscopii is a rapidly rotating star, and PSR J2144-3933 is an unusual pulsar with an unusually long rotation period.

Cecilia Helena Payne

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Cecilia Helena Payne-Gaposchkin (May 10, 1900 – December 7, 1979) was a British-American astronomer and astrophysicist who, in 1925, proposed in her Ph.D. thesis an explanation for the composition of stars in terms of the relative abundances of hydrogen and helium.

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Cecilia at work.

 

 

Doctorate

Shapley persuaded Payne to write a doctoral dissertation, and so in 1925 she became the first person to earn a Ph.D. in astronomy from Radcliffe College (now part of Harvard). Her thesis was “Stellar Atmospheres, A Contribution to the Observational Study of High Temperature in the Reversing Layers of Stars”. Astronomer Otto Struve called it “undoubtedly the most brilliant Ph.D. thesis ever written in astronomy”.

Payne was able to accurately relate the spectral classes of stars to their actual temperatures by applying the ionization theory developed by Indian physicist Meghnad Saha. She showed that the great variation in stellar absorption lines was due to differing amounts of ionization at different temperatures, not to different amounts of elements. She correctly suggested that silicon, carbon, and other common metals seen in the Sun’s spectrum were found in about the same relative amounts as on Earth, but that helium and particularly hydrogen were vastly more abundant (for hydrogen, by a factor of about one million). Her thesis established that hydrogen was the overwhelming constituent of the stars (see Metallicity), and thus the most abundant element in the Universe.

When Payne’s dissertation was reviewed, astronomer Henry Norris Russell dissuaded her from concluding that the composition of the Sun is different from that of the Earth, contradicting the accepted wisdom at the time. However, he changed his mind four years later after deriving the same result by different means. After Payne was proven correct, Russell was often given the credit, although he himself acknowledged her work in his paper.

Early life

Cecilia Helena Payne was one of three children born in Wendover, England to Emma Leonora Helena (née Pertz) and Edward John Payne, a London barrister, historian and accomplished musician. Her mother came from a Prussian family and had two distinguished uncles, historian Georg Heinrich Pertz and the Swedenborgian writer James John Garth Wilkinson. Cecilia Payne’s father died when she was four years old, forcing her mother to raise the family on her own.

She attended St Paul’s Girls’ School. Her mother did not choose to spend money on her college education, but only on her brother’s. In 1919, she won a scholarship to Newnham College, Cambridge University, where she read botany, physics, and chemistry. Here, she attended a lecture by Arthur Eddington on his 1919 expedition to the island of Principe in the Gulf of Guinea off the west coast of Africa to observe and photograph the stars near a solar eclipse as a test of Einstein‘s general theory of relativity. This sparked her interest in astronomy. She completed her studies, but was not awarded a degree because of her sex; Cambridge did not grant degrees to women until 1948.

Cecilia Payne realized that her only career option in the U.K. was to become a teacher, so she looked for grants that would enable her to move to the United States. After meeting Harlow Shapley, the Director of the Harvard College Observatory, who had just begun a graduate program in astronomy, she left England in 1923. This was made possible by a fellowship to encourage women to study at the Observatory. The first student on the fellowship was Adelaide Ames (1922) and the second was Payne.

After her doctorate, Payne studied stars of high luminosity in order to understand the structure of the Milky Way. Later she surveyed all the stars brighter than the tenth magnitude. She then studied variable stars, making over 1,250,000 observations with her assistants. This work later was extended to the Magellanic Clouds, adding a further 2,000,000 observations of variable stars. These data were used to determine the paths of stellar evolution. Her observations and analysis, with her husband, of variable stars laid the basis for all subsequent work on them.

Payne-Gaposchkin remained scientifically active throughout her life, spending her entire academic career at Harvard. At first, she had no official position, merely serving as a technical assistant to Shapley from 1927 to 1938. At one point she considered leaving Harvard because of her low status and poor salary. However, Shapley made efforts to improve her position, and in 1938 she was given the title of “Astronomer”. She later asked to have this title changed to Phillips Astronomer. None of the courses she taught at Harvard were recorded in the catalogue until 1945.

When Donald Menzel became Director of the Harvard College Observatory in 1954, he tried to improve her appointment, and in 1956 she became the first woman to be promoted to full professor from within the faculty at Harvard’s Faculty of Arts and Sciences. Later, with her appointment to the Chair of the Department of Astronomy, she also became the first woman to head a department at Harvard.

Her students included Helen Sawyer Hogg, Joseph Ashbrook, Frank Drake and Paul W. Hodge, who all made important contributions to astronomy. She also supervised Frank Kameny, who became a prominent advocate of gay rights.

Payne-Gaposchkin retired from active teaching in 1966 and was subsequently appointed Emeritus Professor of Harvard. She continued her research as a member of staff at the Smithsonian Astrophysical Observatory.

 

 

The real time machine

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Cosmic Look-Back Time

The finite speed of light means that we must always be out of date, no matter how hard we strive to keep up with the times. Thus, the seemingly simple question – what is happening right now on the Sun? – cannot be answered by an observer on Earth, because it takes light 8 minutes to reach Earth from the Sun.

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Humanism Secular

ChrisColeynotesHumanist

Secular humanism

The philosophy or life stance of secular humanism (alternatively known by some adherents as Humanism, specifically with a capital H to distinguish it from other forms of humanism) embraces human reason, ethics, social justice and philosophical naturalism, while specifically rejecting religious dogma, supernaturalism, pseudoscience or superstition as the basis of morality and decision making.

It posits that human beings are capable of being ethical and moral without religion or a god. It does not, however, assume that humans are either inherently evil or innately good, nor does it present humans as being superior to nature. Rather, the humanist life stance emphasizes the unique responsibility facing humanity and the ethical consequences of human decisions.

Fundamental to the concept of secular humanism is the strongly held viewpoint that ideology—be it religious or political—must be thoroughly examined by each individual and not simply accepted or rejected on faith. Along with this, an essential part of secular humanism is a continually adapting search for truth, primarily through science and philosophy. Many Humanists derive their moral codes from a philosophy of utilitarianism, ethical naturalism or evolutionary ethics, and some advocate a science of morality.

The International Humanist and Ethical Union (IHEU) is the world union of more than one hundred Humanist, rationalist, irreligious, atheistic, Bright, secular, Ethical Culture, and freethought organizations in more than 40 countries. The “Happy Human” is the official symbol of the IHEU as well as being regarded as a universally recognised symbol for those who call themselves Humanists. Secular humanist organizations are found in all parts of the world. Those who call themselves humanists are estimated to number between four and five million people worldwide.

Terminology

The meaning of the phrase secular humanism has evolved over time. The phrase has been used since at least the 1930s, and in 1943, the then Archbishop of Canterbury, William Temple, was reported as warning that the “Christian tradition… was in danger of being undermined by a ‘Secular Humanism’ which hoped to retain Christian values without Christian faith.” During the 1960s and 1970s the term was embraced by some humanists who considered themselves anti-religious, as well as those who, although not critical of religion in its various guises, preferred a non-religious approach. The release in 1980 of A Secular Humanist Declaration by the newly formed Council for Democratic and Secular Humanism (CODESH, now the Council for Secular Humanism) gave secular humanism an organisational identity within the United States.

 

ChrisColeynotesHumanist
Humanist?

However, many adherents of the approach reject the use of the word secular as obfuscating and confusing, and consider that the term secular humanism has been “demonized by the religious right… All too often secular humanism is reduced to a sterile outlook consisting of little more than secularism slightly broadened by academic ethics. This kind of ‘hyphenated humanism’ easily becomes more about the adjective than its referent”.

Adherents of this view, including the International Humanist and Ethical Union and the American Humanist Association, consider that the unmodified but capitalised word Humanism should be used. The endorsement by the IHEU of the capitalization of the word Humanism, and the dropping of any adjective such as secular, is quite recent.

The American Humanist Association began to adopt this view in 1973, and the IHEU formally endorsed the position in 1989. In 2002 the IHEU General Assembly unanimously adopted the Amsterdam Declaration, which represents the official defining statement of World Humanism for Humanists.

This declaration makes exclusive use of capitalized Humanist and Humanism, which is consistent with IHEU’s general practice and recommendations for promoting a unified Humanist identity. To further promote Humanist identity, these words are also free of any adjectives, as recommended by prominent members of IHEU. Such usage is not universal among IHEU member organizations, though most of them do observe these conventions.

 

Age of the Universe

supernova light curves

Age of the Universe – Since The Big Bang?

In physical cosmology, the age of the universe is the time elapsed since the Big Bang. The best measurement of the age of the universe is 13.798±0.037 billion years ((13.798±0.037)×109 years or (4.354±0.012)×1017 seconds) within the Lambda-CDM concordance model.

 

 

The uncertainty of 37 million years has been obtained by the agreement of a number of scientific research projects, such as microwave background radiation measurements by the Planck satellite, the Wilkinson Microwave Anisotropy Probe and other probes.

 

 

Measurements of the cosmic background radiation give the cooling time of the universe since the Big Bang, and measurements of the expansion rate of the universe can be used to calculate its approximate age by extrapolating backwards in time.

Supernova light curves

supernova light curves

Supernova Superlight Sight

The visual light curves of the different supernova types vary in shape and amplitude, based on the underlying mechanisms of the explosion, the way that visible radiation is produced, and the transparency of the ejected material. The light curves can be significantly different at other wavelengths. For example, at UV and shorter wavelengths there is an extremely luminous peak lasting just a few hours, corresponding to the shock breakout of the initial explosion, which is hardly detectable at longer wavelengths.

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The light curves for type Ia are mostly very uniform, with a consistent maximum absolute magnitude and a relatively steep decline in luminosity. The energy output is driven by radioactive decay of nickel-56 (half life 6 days), which then decays to radioactive cobalt-56 (half life 77 days). These radioisotopes from material ejected in the explosion excite surrounding material to incandescence.

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The initial phases of the light curve decline steeply as the effective size of the photosphere decreases and trapped electromagnetic radiation is depleted. The light curve continues to decline in the B band while it may show a small shoulder in the visual at about 40 days, but this is only a hint of a secondary maximum that occurs in the infra-red as certain ionised heavy elements recombine to produce infra-red radiation and the ejecta become transparent to it.

The visual light curve continues to decline at a rate slightly greater than the decay rate of the radioactive cobalt (which has the longer half life and controls the later curve), because the ejected material becomes more diffuse and less able to convert the high energy radiation into visual radiation. After several months, the light curve changes its decline rate again as positron emission becomes dominant from the remaining cobalt-56, although this portion of the light curve has been little-studied.
Type Ib and Ic light curves are basically similar to type Ia although with a lower average peak luminosity. The visual light output is again due to radioactive decay being converted into visual radiation, but there is a much lower mass of nickel-56 produced in these types of explosion. The peak luminosity varies considerably and there are even occasional type Ib/c supernovae orders of magnitude more and less luminous than the norm.

The most luminous type Ic supernovae are referred to as hypernovae and tend to have broadened light curves in addition to the increases peak luminosity. The source of the extra energy is thought to be relativistic jets driven by the formation of a rotating black hole, which also produce gamma-ray bursts.

 

Supernova Discovery

supernova light curves

History and Observation of the Supernova

Early work on what was originally believed to be simply a new category of novae was performed during the 1930s by Walter Baade and Fritz Zwicky at Mount Wilson Observatory. The name super-novae was first used during 1931 lectures held at Caltech by Baade and Zwicky, then used publicly in 1933 at a meeting of the American Physical Society.

By 1938, the hyphen had been lost and the modern name was in use. Because supernovae are relatively rare events within a galaxy, occurring about three times a century in the Milky Way, obtaining a good sample of supernovae to study requires regular monitoring of many galaxies.

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Crab Nebula

Supernovae in other galaxies cannot be predicted with any meaningful accuracy. Normally, when they are discovered, they are already in progress. Most scientific interest in supernovae—as standard candles for measuring distance, for example—require an observation of their peak luminosity. It is therefore important to discover them well before they reach their maximum. Amateur astronomers, who greatly outnumber professional astronomers, have played an important role in finding supernovae, typically by looking at some of the closer galaxies through an optical telescope and comparing them to earlier photographs.

Toward the end of the 20th century astronomers increasingly turned to computer-controlled telescopes and CCDs for hunting supernovae. While such systems are popular with amateurs, there are also professional installations such as the Katzman Automatic Imaging Telescope. Recently the Supernova Early Warning System (SNEWS) project has begun using a network of neutrino detectors to give early warning of a supernova in the Milky Way galaxy. Neutrinos are particles that are produced in great quantities by a supernova explosion, and they are not significantly absorbed by the interstellar gas and dust of the galactic disk.

Hipparchus’ interest in the fixed stars may have been inspired by the observation of a supernova (according to Pliny). The earliest recorded supernova, SN 185, was viewed by Chinese astronomers in 185 AD. The brightest recorded supernova was the SN 1006, which was described in detail by Chinese and Islamic astronomers. The widely observed supernova SN 1054 produced the Crab Nebula. Supernovae SN 1572 and SN 1604, the latest to be observed with the naked eye in the Milky Way galaxy, had notable effects on the development of astronomy in Europe because they were used to argue against the Aristotelian idea that the universe beyond the Moon and planets was immutable. Johannes Kepler began observing SN 1604 on October 17, 1604. It was the second supernova to be observed in a generation (after SN 1572 seen by Tycho Brahe in Cassiopeia).

Since the development of the telescope, the field of supernova discovery has extended to other galaxies, starting with the 1885 observation of supernova S Andromedae in the Andromeda galaxy. American astronomers Rudolph Minkowski and Fritz Zwicky developed the modern supernova classification scheme beginning in 1941. In the 1960s, astronomers found that the maximum intensities of supernova explosions could be used as standard candles, hence indicators of astronomical distances. Some of the most distant supernovae recently observed appeared dimmer than expected.

This supports the view that the expansion of the universe is accelerating. Techniques were developed for reconstructing supernova explosions that have no written records of being observed. The date of the Cassiopeia A supernova event was determined from light echoes off nebulae, while the age of supernova remnant RX J0852.0-4622 was estimated from temperature measurements and the gamma ray emissions from the decay of titanium-44. In 2009, nitrates were discovered in Antarctic ice deposits that matched the times of past supernova events.

the causes and symptons of emphysema

Adapt-logoWhat is Alpha-1 Antitrypsin Deficiency?

Alpha-1 Antitrypsin Deficiency also known as Alpha-1, A1AD or AATD is an inherited, genetic condition that is passed on from generation to generation. As the name suggests it is a deficiency of alpha-1 antitrypsin (AAT) in the bloodstream. AAT is an enzyme produced in the liver to help protect the tissues of the body during infections.

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Alpha-1

The low level of AAT in the blood occurs because the AAT is abnormal and cannot be released from the liver at the normal rate. This leads to a build up of abnormal AAT in the liver that can cause liver disease and a decrease of AAT in the blood that can lead to lung disease.

What is ADAPT?

ADAPT (Antitrypsin Deficiency Assessment and Programme for Treatment) has been established by research doctors who have an international reputation for their research into the causes of emphysema, in collaboration with the pharmaceutical company Bayer.

ADAPT’s mission is to rapidly collect important information about how AAT deficiency affects you and your family. In addition to being helpful to you in understanding the effects of AAT deficiency on your lungs, this information will be critical to the design of clinical studies of the effects of treatment of the disease.
Finally, ADAPT will provide an information service to you and your relatives to explain how AAT deficiency influences you, your health, and your lifestyle.

Alpha-1-4cure

 

 

 

 

 

 

 

 

 
 

 

Latest hubble april25th

Hubble Space Telescope

Astronomical Forensics Uncover Planetary Disks in NASA’s Hubble Archive

Astronomers using NASA’s Hubble Space Telescope have applied a new image processing technique to obtain near-infrared scattered light photos of five disks observed

around young stars in the Mikulski Archive for Space Telescopes database. These disks are telltale evidence for newly formed planets.

If astronomers initially miss something in their review of data, they can make new discoveries by revisiting earlier data with new image processing techniques, thanks to the wealth

of information stored in the Hubble data archive. This is what Rémi Soummer, of the Space Telescope Science Institute (STScI) in Baltimore, Md., and his team recently did while

on a hunt for hidden Hubble treasures.

The stars in question initially were targeted with Hubble’s Near Infrared Camera and Multi-Object Spectrometer (NICMOS) based on unusual heat signatures obtained from

NASA’s Spitzer Space Telescope and the Infrared Astronomical Satellite that flew in 1983. The previous data provided interesting clues that dusty disks could exist around these

stars. Small dust particles in the disks might scatter light and therefore make the disks visible. But when Hubble first viewed the stars between 1999 and 2006, no disks weredetected in the NICMOS pictures

Mars is Cool!

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Mars Orbit

It’s the Rock ‘n Roll Planet

Mars has approximately half the diameter of Earth. It is less dense than Earth, having about 15% of Earth’s volume and 11% of the mass. Its surface area is only slightly less than the total area of Earth’s dry land. While Mars is larger and more massive than Mercury, Mercury has a higher density.

This results in the two planets having a nearly identical gravitational pull at the surface – that of Mars is stronger by less than 1%.

The red-orange appearance of the Martian surface is caused by iron(III) oxide, more commonly known as hematite, or rust. It can also look butterscotch, and other common surface colors include golden, brown, tan, and greenish, depending on minerals.

 

 

 

 

 

It’s All Within Orion

A detailed list of the contents within Orion.

Orion is a prominent constellation located on the celestial equator and visible throughout the world. It is one of the most conspicuous and recognizable constellations in the night sky. It was named after Orion, a hunter in Greek mythology. Its brightest stars are Rigel (Beta Orionis) and Betelgeuse (Alpha Orionis), a blue-white and a red supergiant respectively. Many of the other brighter stars in the constellation are hot, blue supergiant stars. The three stars in the middle of the constellation form an asterism known as Orion’s belt. The Orion Nebula is located south of Orion’s belt.

Stars

  • Betelgeuse, known alternatively by its Bayer designation Alpha Orionis, is a massive M-type red supergiant star nearing the end of its life. When it explodes it will even be visible during the day. It is the second brightest star in Orion, and is a semiregular variable star. It serves as the “right shoulder” of the hunter it represents (assuming that he is facing the observer), and is the eighth brightest star in the night sky.
  • Rigel, which is also known as Beta Orionis, is a B-type blue supergiant that is the sixth brightest star in the night sky. Similar to Betelgeuse, Rigel is fusingheavy elements in its core and will pass its supergiant stage soon (on an astronomical timescale), either collapsing in the case of a supernova or shedding its outer layers and turning into a white dwarf. It serves as the left foot of Orion, the hunter.
  • Bellatrix was designated Gamma Orionis by Johann Bayer, but is known colloquially as the “Amazon Star”. It is the twenty-seventh brightest star in the night sky. Bellatrix is considered a B-type blue giant, though it is too small to explode in a supernova. Bellatrix’s luminosity is derived from its high temperature rather than its radius, a factor that defines Betelgeuse. Bellatrix serves as Orion’s left shoulder.
  • Mintaka garnered the name Delta Orionis from Bayer, even though it is the faintest of the three stars in Orion’s Belt. Its name means “the Giant’s belt”. It is a multiple star system, composed of a large B-type blue giant and a more massive O-type white star. The Mintaka system constitutes an eclipsing binary variable star, where the eclipse of one star over the other creates a dip in brightness. Mintaka is the westernmost of the three stars of Orion’s Belt, as well as the northernmost.
  • Alnilam is designated Epsilon Orionis, a consequence of Bayer’s wish to name the three stars in Orion’s Belt (from north to south) in alphabetical order. Also called Al Nathin, Alnilam is named for the Arabic phrase meaning “string of pearls”. Alnilam is a B-type blue supergiant; despite being nearly twice as far from the Sun as Mintaka and Alnitak, the other two belt stars, its luminosity makes it nearly equal in magnitude. Alnilam is losing mass quickly, a consequence of its size; it is approximately four million years old.
  • Alnitak, meaning “the girdle”,was designated Zeta Orionis by Bayer, and is the easternmost star in Orion’s Belt. It is a triple star some 800 light years distant, with the primary star being a hot blue supergiant and the brightest class Ostar in the night sky.
  • Saiph was designated Kappa Orionis by Bayer, and serves as Orion’s right foot. It is of a similar distance and size to Rigel, but appears much fainter, as its hot surface temperature (46,000°F or 26,000°C) causes it to emit most of its light in the ultraviolet region of the spectrum.

Of the lesser stars, Hatsya (or Iota Orionis) forms the tip of Orion’s sword, whilst Meissa (or Lambda Orionis) forms Orion’s head. Iota Orionis is also called Nair al-Saif, Arabic for “the brightest in the sword”.

Orion’s Belt

Hanging from Orion’s belt is his sword, consisting of the multiple stars θ1 and θ2 Orionis, called the Trapezium and the Orion Nebula (M42). This is a spectacular object that can be clearly identified with the naked eye as something other than a star. Using binoculars, its clouds of nascent stars, luminous gas, and dust can be observed. The Trapezium cluster has many newborn stars, including several brown dwarfs, all of which are at an approximate distance of 1,500 light-years. Named for the four bright stars that form a trapezoid, it is largely illuminated by the brightest stars, which are only a few hundred thousand years old. Observations by the Chandra X-ray Observatory show both the extreme temperatures of the main stars—up to 60,000 Kelvin—and the star forming regions still extant in the surrounding nebula.

M78 (NGC 2068) is a nebula in Orion. With an overall magnitude of 8.0, it is significantly dimmer than the Great Orion Nebula that lies to its south; however, it is at approximately the same distance, at 1600 light-years from Earth. It can easily be mistaken for a comet in the eyepiece of a telescope. M78 is associated with the variable starV351 Orionis, whose magnitude changes are visible in very short periods of time. Another fairly bright nebula in Orion is NGC 1999, also close to the Great Orion Nebula. It has an integrated magnitude of 10.5 and is 1500 light-years from Earth. The variable star V380 Orionis is embedded in NGC 1999.

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Orion Constellation

 

Another famous nebula is IC 434, the Horsehead Nebula, near ζ Orionis. It contains a dark dust cloud whose shape gives the nebula its name.

Besides these nebulae, surveying Orion with a small telescope will reveal a wealth of interesting deep-sky objects, including M43, M78, as well as multiple stars including Iota Orionis and Sigma Orionis. A larger telescope may reveal objects such as Barnard’s Loop and the Flame Nebula (NGC 2024), as well as fainter and tighter multiple stars and nebulae.

All of these nebulae are part of the larger Orion Molecular Cloud Complex, which is located approximately 1,500 light-years away and is hundreds of light-years across. It is one of the most intense regions of stellar formation visible in our galaxy.

Infrared In Astronomy

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Infrared astronomy is the branch of astronomy and astrophysics that studies astronomical objects visible in infrared (IR) radiation. The wavelength of infrared light ranges from 0.75 to 300 micrometers. Infrared falls in between visible radiation, which ranges from 380 to 750 nanometers, and submillimeter waves.

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Emission Neb Head

Infrared astronomy began in the 1830s, a few decades after the discovery of infrared light by William Herschel in 1800. Early progress was limited, and it was not until the early 20th century that conclusive detections of astronomical objects other than the Sun and Moon were detected in infrared light. After a number of discoveries were made in the 1950s and 1960s in radio astronomyastronomers realized the information available outside of the visible wavelength range, and modern infrared astronomy was established.

Infrared and optical astronomy are often practiced using the same telescopes, as the same mirrors or lenses are usually effective over a wavelength range that includes both visible and infrared light. Both fields also use solid state detectors, though the specific type of solid state detectors used are different. Infrared light is absorbed at many wavelengths by water vapor in the Earth’s atmosphere, so most infrared telescopes are at high elevations in dry places, above as much of the atmosphere as possible. There are also infrared observatories in space, including the Spitzer Space Telescope and the Herschel Space Observatory.

 

The discovery of infrared radiation is attributed to William Herschel, who performed an experiment where he placed a thermometer in sunlight of different colors after it passed through a prism. He noticed that the temperature increase induced by sunlight was highest outside the visible spectrum, just beyond the red color. That the temperature increase was highest at infrared wavelengths was due to the spectral index of the prism rather than properties of the Sun, but the fact that there was any temperature increase at all prompted Herschel to deduce that there was invisible radiation from the Sun. He dubbed this radiation “calorific rays”, and went on to show that it could be reflected, transmitted, and absorbed just like visible light.

Efforts were made starting in the 1830s and continuing through the 19th century to detect infrared radiation from other astronomical sources. Radiation from the Moon was first detected in 1873 by William Parsons, 3rd Earl of RosseErnest Fox Nichols used a modified Crookes radiometer in an attempt to detect infrared radiation from Arcturus and Vega, but Nichols deemed the results inconclusive. Even so, the ratio of flux he reported for the two stars is consistent with the modern value, so George Rieke gives Nichols credit for the first detection of a star other than our own in the infrared.

The field of infrared astronomy continued to develop slowly in the early 20th century, as Seth Barnes Nicholson and Edison Pettit developed thermopile detectors capable of accurate infrared photometry and sensitive to a few hundreds of stars. The field was mostly neglected by traditional astronomers though until the 1960s, with most scientists who practiced infrared astronomy having actually been trained physicists. The success of radio astronomy during the 1950s and 1960s, combined with the improvement of infrared detector technology, prompted more astronomers to take notice, and infrared astronomy became well established as a subfield of astronomy.

 

Use Command Prompt To Check Windows System Files

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Run the System File Checker tool (SFC.exe)

You can use the program by just right-clicking the hard drive icon (usually the C:Drive) and looking under “tools”. For a more thorough check though, try using the Command Prompt option.

Windows 7 or Windows Vista To do this, click Start, type Command Prompt or cmd in the Search box, right-click Command Prompt, and then click Run as administrator.

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Run as Admin

 

If you are prompted for an administrator password or for a confirmation, type the password, or click Allow.

At the command prompt, type the following command, and then press ENTER:

sfc /scannow

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The sfc /scannow command will scan all protected system files, and replace corrupted files with a cached copy that is located in a compressed folder at %WinDir%\System32\dllcache. The %WinDir% placeholder represents the Windows operating system folder. For example, C:\Windows.

Note Do not close this Command Prompt window until the verification is 100% complete. The scan results will be shown after this process is finished.


After the process is finished, you may receive one of the following messages:

* Windows Resource Protection did not find any integrity violations.

This means that you do not have any missing or corrupted system files.

 * Windows Resource Protection could not perform the requested operation.

 To resolve this problem, perform the System File Checker scan in safe mode, and make sure that the PendingDeletes and PendingRenames folders exist under %WinDir%\WinSxS\Temp.

 * Windows Resource Protection found corrupt files and successfully repaired them. Details are included in the CBS.Log %WinDir%\Logs\CBS\CBS.log.

 To view the detail information about the system file scan and restoration, go to How to view details of the System File Checker process.

 * Windows Resource Protection found corrupt files but was unable to fix some of them. Details are included in the CBS.Log %WinDir%\Logs\CBS\CBS.log.

 

To repair the corrupted files manually, view details of the System File Checker process to find the corrupted file, and then manually replace the corrupted file with a known good copy of the file.

 

 

 

 

Could It Be A Crunch of An Ending?

The Big Crunch

In physical cosmology, the Big Crunch is one possible scenario for the ultimate fate of the universe, in which the metric expansion of space eventually reverses and the universe collapses, ultimately ending as a black hole singularity or causing a reformation of the universe starting with another big bang. Sudden singularities and crunch or rip singularities at late times occur only for hypothetical matter with implausible physical properties.

If the universe is finite in extent and the cosmological principle (not to be confused with the cosmological constant) does not apply, and the expansion speed does not exceed the escape velocity, then the mutual gravitational attraction of all its matter will eventually cause it to contract. If entropy continues to increase in the contracting phase (see Ergodic hypothesis), the contraction would appear very different from the time reversal of the expansion. While the early universe was highly uniform, a contracting universe would become increasingly clumped. Eventually all matter would collapse into black holes, which would then coalesce producing a unified black hole or Big Crunch singularity.

The Hubble Constant measures the current state of expansion in the universe, and the strength of the gravitational force depends on the density and pressure of the matter and in the universe, or in other words, the critical density of the universe. If the density of the universe is greater than the critical density, then the strength of the gravitational force will stop the universe from expanding and the universe will collapse back on itself—assuming that there is no repulsive force such as a cosmological constant.

Conversely, if the density of the universe is less than the critical density, the universe will continue to expand and the gravitational pull will not be enough to stop the universe from expanding. This scenario would result in the ‘Big Freeze’, where the universe cools as it expands and reaches a state of entropy. One theory proposes that the universe could collapse to the state where it began and then initiate another Big Bang, so in this way the universe would last forever, but would pass through phases of expansion (Big Bang) and contraction (Big Crunch).

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We all crunch together.

Recent experimental evidence (namely the observation of distant supernovae as standard candles, and the well-resolved mapping of the cosmic microwave background) has led to speculation that the expansion of the universe is not being slowed down by gravity but rather accelerating.

 

 

 

However, since the nature of the dark energy that is postulated to drive the acceleration is unknown, it is still possible (though not observationally supported as of today) that it might eventually reverse sign and cause a collapse.

 

 

 

The universe is much bigger than the observable universe post I did yesterday

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Some parts of the universe may simply be too far away – an under-statement maybe too…

Some parts of the universe may simply be too far away for the light emitted from there at any moment since the Big Bang to have had enough time to reach Earth at present, so these portions of the universe would currently lie outside the observable universe.

In the future, light from distant galaxies will have had more time to travel, so some regions not currently observable will become observable. However, due to Hubble’s law regions sufficiently distant from us are expanding away from us much faster than the speed of light (special relativity prevents nearby objects in the same local region from moving faster than the speed of light with respect to each other, but there is no such constraint for distant objects when the space between them is expanding; see uses of the proper distance for a discussion), and the expansion rate appears to be accelerating due to dark energy.

Assuming dark energy remains constant (an unchanging cosmological constant), so that the expansion rate of the universe continues to accelerate, there is a “future visibility limit” beyond which objects will never enter our observable universe at any time in the infinite future, because light emitted by objects outside that limit would never reach us. (A subtlety is that, because the Hubble parameter is decreasing with time, there can be cases where a galaxy that is receding from us just a bit faster than light does emit a signal that reaches us eventually).

This future visibility limit is calculated at a comoving distance of 19 billion parsecs (62 billion light years) assuming the universe will keep expanding forever, which implies the number of galaxies that we can ever theoretically observe in the infinite future (leaving aside the issue that some may be impossible to observe in practice due to redshift, as discussed in the following paragraph) is only larger than the number currently observable by a factor of 2.36.

Some parts of the universe may simply be too far away for the light emitted from there at any moment since the Big Bang to have had enough time to reach Earth at present, so these portions of the universe would currently lie outside the observable universe. In the future, light from distant galaxies will have had more time to travel, so some regions not currently observable will become observable. However, due to Hubble’s law regions sufficiently distant from us are expanding away from us much faster than the speed of light (special relativity prevents nearby objects in the same local region from moving faster than the speed of light with respect to each other, but there is no such constraint for distant objects when the space between them is expanding; see uses of the proper distance for a discussion), and the expansion rate appears to be accelerating due to dark energy.

Assuming dark energy remains constant (an unchanging cosmological constant), so that the expansion rate of the universe continues to accelerate, there is a “future visibility limit” beyond which objects will never enter our observable universe at any time in the infinite future, because light emitted by objects outside that limit would never reach us. (A subtlety is that, because the Hubble parameter is decreasing with time, there can be cases where a galaxy that is receding from us just a bit faster than light does emit a signal that reaches us eventually).

This future visibility limit is calculated at a comoving distance of 19 billion parsecs (62 billion light years) assuming the universe will keep expanding forever, which implies the number of galaxies that we can ever theoretically observe in the infinite future (leaving aside the issue that some may be impossible to observe in practice due to redshift, as discussed in the following paragraph) is only larger than the number currently observable by a factor of 2.36.

The Observable Universe – From Earth

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The observable universe consists of the galaxies and other matter that can, in principle, be observed from Earth in the present day because light (or other signals) from those objects has had time to reach the Earth since the beginning of the cosmological expansion. Assuming the universe is isotropic, the distance to the edge of the observable universe is roughly the same in every direction. That is, the observable universe is a spherical volume (a ball) centered on the observer, regardless of the shape of the universe as a whole. Every location in the universe has its own observable universe, which may or may not overlap with the one centered on Earth.

The diameter of the observable universe is estimated at about 28 billion parsecs (93 billion light-years), putting the edge of the observable universe at about 46–47 billion light-years away.

The word observable used in this sense does not depend on whether modern technology actually permits detection of radiation from an object in this region (or indeed on whether there is any radiation to detect). It simply indicates that it is possible in principle for light or other signals from the object to reach an observer on Earth. In practice, we can see light only from as far back as the time of photon decoupling in the recombination epoch. That is when particles were first able to emit photons that were not quickly re-absorbed by other particles. Before then, the universe was filled with a plasma that was opaque to photons.

The surface of last scattering is the collection of points in space at the exact distance that photons from the time of photon decoupling just reach us today. These are the photons we detect today as cosmic microwave background radiation (CMBR). However, with future technology, it may be possible to observe the still older neutrino background, or even more distant events via gravitational waves (which also should move at the speed of light). Sometimes astrophysicists distinguish between the visible universe, which includes only signals emitted since recombination—and the observable universe, which includes signals since the beginning of the cosmological expansion (the Big Bang in traditional cosmology, the end of the inflationary epoch in modern cosmology). According to calculations, the comoving distance (current proper distance) to particles from the CMBR, which represent the radius of the visible universe, is about 14.0 billion parsecs (about 45.7 billion light years), while the comoving distance to the edge of the observable universe is about 14.3 billion parsecs (about 46.6 billion light years), about 2% larger.

 

The best estimate of the age of the universe as of 2013 is 13.798 ± 0.037 billion years but due to the expansion of space humans are observing objects that were originally much closer but are now considerably farther away (as defined in terms of cosmological proper distance, which is equal to the comoving distance at the present time) than a static 13.8 billion light-years distance. The diameter of the observable universe is estimated at about 28 billion parsecs (93 billion light-years), putting the edge of the observable universe at about 46–47 billion light-years away.

 

 

 

 

Stars in Aries

Constellation Star Features

Aries has three prominent stars forming an asterism, designated Alpha, Beta, and Gamma Arietis by Johann Bayer. All three are commonly used for navigation. There is also one other star above the fourth magnitude, 41 Arietis. α Arietis, called Hamal, is the brightest star in Aries. Its traditional name is derived from the Arabic word for “lamb” or “head of the ram” (ras al-hamal), which references Aries’s mythological background. With a spectral class of K2 and a luminosity class of III, it is an orange giant with an apparent visual magnitude of 2.00, which lies 66 light-years from Earth. Hamal has a luminosity of 96 L and its absolute magnitude is −0.1.

β Arietis, also known as Sheratan, is a blue-white star with an apparent visual magnitude of 2.64. Its traditional name is derived from “sharatayn“, the Arabic word for “the two signs”, referring to both Beta and Gamma Arietis in their position as heralds of the vernal equinox. The two stars were known to the Bedouin as “qarna al-hamal“, “horns of the ram”. It is 59 light-years from Earth. It has a luminosity of 11 L and its absolute magnitude is 2.1. It is a spectroscopic binary star, one in which the companion star is only known through analysis of the spectra. The spectral class of the primary is A5. Hermann Carl Vogel determined that Sheratan was a spectroscopic binary in 1903; its orbit was determined by Hans Ludendorff in 1907. It has since been studied for its eccentric orbit.

γ Arietis, with a common name of Mesarthim, is a binary star with two white-hued components, located in a rich field of magnitude 8–12 stars. Its traditional name has conflicting derivations. It may be derived from a corruption of “al-sharatan”, the Arabic word meaning “pair” or a word for “fat ram”.However, it may also come from the Sanskrit for “first star of Aries” or the Hebrew for “ministerial servants”, both of which are unusual languages of origin for star names. Along with Beta Arietis, it was known to the Bedouin as “qarna al-hamal“. The primary is of magnitude 4.59 and the secondary is of magnitude 4.68. The system is 164 light-years from Earth. The two components are separated by 7.8 arcseconds. The whole system as a whole has an apparent magnitude of 3.9. The primary has a luminosity of 60 L and the secondary has a luminosity of 56 L; the primary is an A-type star with an absolute magnitude of 0.2 and the secondary is a B9-type star with an absolute magnitude of 0.4. The angle between the two components is 1°. Mesarthim was discovered to be a double star by Robert Hooke in 1664, one of the earliest such telescopic discoveries. The primary, γ1 Arietis, is an Alpha² Canum Venaticorum variable star that has a range of 0.02 magnitudes and a period of 2.607 days. It is unusual because of its strong silicon emission lines.

The constellation is home to several double stars, including Epsilon, Lambda, and Pi Arietis. ε Arietis is a binary star with two white components. The primary is of magnitude 5.2 and the secondary is of magnitude 5.5. The system is 290 light-years from Earth. Its overall magnitude is 4.63, and the primary has an absolute magnitude of 1.4. Its spectral class is A2. The two components are separated by 1.5 arcseconds. λ Arietis is a wide double star with a white-hued primary and a yellow-hued secondary. The primary is of magnitude 4.8 and the secondary is of magnitude 7.3. The primary is 129 light-years from Earth. It has an absolute magnitude of 1.7 and a spectral class of F0. The two components are separated by 36 arcseconds at an angle of 50°; the two stars are located 0.5° east of 7 Arietis. π Arietis is a close binary star with a blue-white primary and a white secondary. The primary is of magnitude 5.3 and the secondary is of magnitude 8.5. The primary is 776 light-years from Earth. The primary itself is a wide double star with a separation of 25.2 arcseconds; the tertiary has a magnitude of 10.8. The primary and secondary are separated by 3.2 arcseconds.

Most of the other stars in Aries visible to the naked eye have magnitudes between 3 and 5. δ Ari, called Boteïn, is a star of magnitude 4.35, 170 light-years away. It has an absolute magnitude of −0.1 and a spectral class of K2. ζ Arietis is a star of magnitude 4.89, 263 light-years away. Its spectral class is A0 and its absolute magnitude is 0.0. 14 Arietis is a star of magnitude 4.98, 288 light-years away. Its spectral class is F2 and its absolute magnitude is 0.6. 39 Arietis is a similar star of magnitude 4.51, 172 light-years away. Its spectral class is K1 and its absolute magnitude is 0.0. 35 Arietis is a dim star of magnitude 4.55, 343 light-years away. Its spectral class is B3 and its absolute magnitude is −1.7. 41 Arietis, known both as c Arietis and Nair al Butain, is a brighter star of magnitude 3.63, 165 light-years away. Its spectral class is B8 and it has a luminosity of 105 L. Its absolute magnitude is −0.2. 53 Arietis is arunaway star of magnitude 6.09, 815 light-years away. Its spectral class is B2. It was likely ejected from the Orion Nebula approximately five million years ago, possibly due tosupernovae. Finally, Teegarden’s Star is the closest star to Earth in Aries. It is a brown dwarf of magnitude 15.14 and spectral class M6.5V. With a proper motion of 5.1 arcseconds per year, it is the 24th closest star to Earth overall.

Aries has its share of variable stars, including R and U Arietis, Mira-type variable stars, and T Arietis, a semi-regular variable star. R Arietis is a Mira variable star that ranges in magnitude from a minimum of 13.7 to a maximum of 7.4 with a period of 186.8 days. It is 4,080 light-years away. U Arietis is another Mira variable star that ranges in magnitude from a minimum of 15.2 to a maximum of 7.2 with a period of 371.1 days. T Arietis is a semiregular variable star that ranges in magnitude from a minimum of 11.3 to a maximum of 7.5 with a period of 317 days. It is 1,630 light-years away. One particularly interesting variable in Aries is SX Arietis, a rotating variable star considered to be the prototype of its class, helium variable stars. SX Arietis stars have very prominent emission lines of Helium I and Silicon III. They are normally main-sequence B0p—B9p stars, and their variations are not usually visible to the naked eye. Therefore, they are observed photometrically, usually having periods that fit in the course of one night. Similar to Alpha² Canum Venaticorum variables, SX Arietis stars have periodic changes in their light and magnetic field, which correspond to the periodic rotation; they differ from the Alpha² Canum Venaticorum variables in their higher temperature. There are between 39 and 49 SX Arietis variable stars currently known; ten are noted as being “uncertain” in the General Catalog of Variable Stars

Pseudoscience

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Pseudoscience is a claim, belief, or practice which is presented as scientific, but does not adhere to a valid scientific method, lacks supporting evidence or plausibility, cannot be reliably tested, or otherwise lacks scientific status.

Pseudoscience is often characterized by the use of vague, contradictory, exaggerated or unprovable claims, an over-reliance on confirmation rather than rigorous attempts at refutation, a lack of openness to evaluation by other experts, and a general absence of systematic processes to rationally develop theories.

The Aries Constellation

Aries is one of the constellations of the zodiac. It is located in the northern celestial hemisphere between Pisces to the west and Taurus to the east. The name Aries is Latin for ram, and its symbol is  (Unicode ♈), representing a ram’s horns.

It is one of the 48 constellations described by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations. It is a mid-sized constellation, ranking 39th overall size, with an area of 441 square degrees (1.1% of the celestial sphere).

Although Aries came to represent specifically the ram whose fleece became the Golden Fleece of Ancient Greek mythology, it has represented a ram since late Babylonian times. Before that, the stars of Aries formed a farmhand. Different cultures have incorporated the stars of Aries into different constellations including twin inspectors in China and a porpoise in the Marshall Islands. Aries is a relatively dim constellation, possessing only four bright stars: Hamal (Alpha Arietis, second magnitude), Sheratan (Beta Arietis, third magnitude), Mesarthim (Gamma Arietis, fourth magnitude), and 41 Arietis (also fourth magnitude). The few deep-sky objects within the constellation are quite faint and include several pairs of interacting galaxies. Several meteor showers appear to radiate from Aries, including the Daytime Arietids and the Epsilon Arietids.

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Aries – In Naked Naked Eye View

Exoplanets are Extra Solar

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Extra Solar Outside Solar System

An exoplanet, or extrasolar planet, is a planet outside the Solar System. More than a thousand such planets have been discovered (1048 planets in 794 planetary systems including 175 multiple planetary systems as of 25 November 2013). As of 4 November 2013, the Kepler mission space telescope has detected 3,568 more candidate planets, of which about 11% may be false positives.

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It is expected that there are many billions of planets in the Milky Way Galaxy (at least one planet, on average, orbiting around each star, resulting in 100–400 billion exoplanets), with many more free-floating planetary-mass bodies orbiting within the galaxy.

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Constellation of Lyra

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Lyra is a small constellation – with a big star

 

It is one of 48 listed by the 2nd century astronomer Ptolemy, and is one of the 88 constellations recognized by the International Astronomical Union. Its principal star, Vega (Abhijit in Sanskrit), a corner of the Summer Triangle, is one of the brightest stars in the sky. Beginning at the north, Lyra is bordered by Draco, Hercules, Vulpecula, and Cygnus.

Cygnus, Lyra
Lyra naked eye.

Lyra is visible from the northern hemisphere from spring through autumn, and nearly overhead, in temperate latitudes, during the summer months. From the southern hemisphere, it is visible low in the northern sky during the winter months.

Mythology

In Greek mythology, Lyra was associated with the myth of Orpheus, the musician who was killed by the Bacchantes. After his death, his lyre was thrown into the river; Zeus sent an eagle to retrieve the lyre, and ordered both of them to be placed in the sky. In Wales, Lyra is known as King Arthur’s Harp (Talyn Arthur), and King David’s harp. The Persian Hafiz called it the Lyre of Zurah. It has been called the Manger of the Infant Saviour, Praesepe Salvatoris. In Japan, Vega is sometimes called Tanabata (or Orihime), a celestial princess or goddess. She falls in love with a mortal, Kengyu (or Hikoboshi), represented by the star Altair. But when Tanabata’s father finds out, he is enraged and forbids her to see this mere mortal. Thus the two lovers are placed in the sky, where they are separated by the Celestial River, known to us as Milky Way. Yet the sky gods are kind. Each year, on the 7th night of the 7th moon, a bridge of magpies forms across the Celestial River, and the two lovers are reunited. Sometimes Kengyu’s annual trip across the Celestial River is treacherous, though, and he doesn’t make it. In that case, Tanabata’s tears form raindrops that fall over Japan.

Vega

Big Vega Star – in small constellation of Lyra.

It’s the brightest star in the constellation Lyra, the fifth brightest star in the night sky and the second brightest star in the northern celestial hemisphere, after Arcturus. It is a relatively close star at only 25 light-years from Earth, and, together with Arcturus and Sirius, one of the most luminous stars in the Sun‘s neighborhood.

Vega has been extensively studied by astronomers, leading it to be termed “arguably the next most important star in the sky after the Sun.”

 

Vega was the northern pole star around 12,000 BCE and will be so again around the year 13,727 when the declination will be +86°14′. Vega was the first star other than the Sun to be photographed and the first to have its spectrum recorded. It was one of the first stars whose distance was estimated through parallax measurements. Vega has served as the baseline for calibrating the photometric brightness scale, and was one of the stars used to define the mean values for the UBV photometric system.

the sun – our solar system

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Our Star – The Sun

The Sun formed about 4.6 billion years ago..

It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields.

It has a diameter of about 1,392,684 km (865,374 mi), around 109 times that of Earth, and its mass (1.989×1030 kilograms, approximately 330,000 times the mass of Earth) accounts for about 99.86% of the total mass of the Solar System.

Chemically, about three quarters of the Sun’s mass consists of hydrogen, while the rest is mostly helium. The remainder (1.69%, which nonetheless equals 5,600 times the mass of Earth) consists of heavier elements, including oxygen, carbon, neon and iron, among others.

The Sun formed about 4.6 billion years ago from the gravitational collapse of a region within a large molecular cloud. Most of the matter gathered in the center, while the rest flattened into an orbiting disk that would become the Solar System.

The central mass became increasingly hot and dense, eventually initiating thermonuclear fusion in its core. It is thought that almost all stars form by this process. The Sun is classified as a G-type main-sequence star (G2V) based on spectral class and it is informally designated as a yellow dwarf because its visible radiation is most intense in the yellow-green portion of the spectrum, and although it is actually white in color, from the surface of the Earth it may appear yellow because of atmospheric scattering of blue light.

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Eye Coleyartastro and the Sun

In the spectral class label, G2 indicates its surface temperature, of approximately 5778 K (5505 °C), and V indicates that the Sun, like most stars, is a main-sequence star, and thus generates its energy by nuclear fusion of hydrogen nuclei into helium.

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solar sun eclip

Andromeda Near Milky Way

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Future collision with the Milky Way

The Andromeda Galaxy is approaching the Milky Way at about 300 kilometres per second (190 mi/s), making it one of the few blueshifted galaxies. The Andromeda Galaxy and the Milky Way are thus expected to collide in about 3.75 or 4.5 billion years, although the details are uncertain since Andromeda’s tangential velocity with respect to the Milky Way is known to only within about a factor of two.

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A likely outcome of the collision is that the galaxies will merge to form a giant elliptical galaxy. Such events are frequent among the galaxies in galaxy groups. The fate of the Earth and the Solar System in the event of a collision is currently unknown. If the galaxies do not merge, there is a small chance that the Solar System could be ejected from the Milky Way or join M31.

The spiral arms of M31 are outlined by a series of H II regions that Baade described as resembling “beads on a string”. They appear to be tightly wound, although they are more widely spaced than in our galaxy. Since the Andromeda Galaxy is seen close to edge-on, however, the studies of its spiral structure are difficult.

While rectified images of the galaxy seem to show a fairly normal spiral galaxy with the arms wound up in a clockwise direction, existing two continuous trailing arms that are separated from each other by a minimum of about 13,000 light-years (820,000,000 AU) and that can be followed outward from a distance of roughly 1,600 light-years (100,000,000 AU) from the core, other alternative spiral structures have been proposed such as a single spiral arm or a flocculent pattern of long, filamentary, and thick spiral arms.

Lepus (Is under Orion)

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Lepus (constellation)

Lepus could remain anonymous unless posted about. It happens to be “under” the glorious Orion and may become ignored if not for constellation lovers like me! So please give Lepus credit somewhere.

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Lepus constellation image

This constellation should not be confused with Lupus, the wolf.

Lepus is a constellation lying just south of the celestial equator, immediately south of Orion. Its name is Latin for hare. Although the hare does not represent any particular figure in Greek mythology, Lepus was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and it remains one of the 88 modern constellations. It is located below the constellation Orion (the hunter), and is sometimes represented as a hare being chased by Orion or, alternatively, by Orion’s hunting dogs.

The Moon rabbit in folklore is a rabbit that lives on the moon, based on pareidolia that identifies the markings of the moon as a rabbit. The story exists in many cultures, particularly in Aztec mythology and East Asian folklore, where it is seen pounding in a mortar and pestle. In Chinese folklore, it is often portrayed as a companion of the moon goddess Chang’e, constantly pounding the elixir of life for her; but in Japanese and Korean versions, it is just pounding the ingredients for rice cake.

The List of Stars in Lepus

There are a fair number of bright stars, both single and double, in Lepus. Alpha Leporis, the brightest star of Lepus, is a white supergiant of magnitude 2.6, 1300 light-years from Earth. Its traditional name, Arneb, means “hare”. Beta Leporis, called Nihal, is a yellow giant of magnitude 2.8, 159 light-years from Earth. Gamma Leporis is a double star divisible in binoculars. The primary is a yellow star of magnitude 3.6, 29 light-years from Earth. The secondary is an orange star of magnitude 6.2. Delta Leporis is a yellow giant of magnitude 3.8, 112 light-years from Earth. Epsilon Leporis is an orange giant of magnitude 2.2, 227 light-years from Earth. Kappa Leporis is a double star divisible in medium aperture amateur telescopes, 560 light-years from Earth. The primary is a blue-white star of magnitude 4.4 and the secondary is a star of magnitude 7.4.

 

There are several variable stars in Lepus. R Leporis is a Mira variable star also called “Hind’s Crimson Star” for its striking red color. It varies in magnitude from a minimum of 9.8 to a maximum of 7.3, with a period of 420 days. R Leporis is at a distance of 1500 light-years. The color intensifies as the star brightens. It can be as dim as magnitude 12 and as bright as magnitude 5.5. It was named for John Russell Hind. T Leporis is also a Mira variable observed in detail by ESO‘s Very Large TelescopeInterferometer. RX Leporis is a semi-regularred giant that has a period of 2 months. It has a minimum magnitude of 7.4 and a maximum magnitude of 5.0.

The Hercules Constellation

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Hercules is a constellation named after Hercules, the Roman mythological hero adapted from the Greek hero Heracles. Hercules was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and it remains one of the 88 modern constellations today. It is the fifth largest of the modern constellations.

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Hercules Constellation

Hercules has no first or second magnitude
stars. However, it does have several stars above magnitude 4. Alpha Herculis, traditionally called
Rasalgethi, is a binary star resolvable in small
amateur telescopes, 400 light-years from Earth. The primary is an irregular variable star; it is a red giant with a minimum magnitude
of 4 and a maximum magnitude of 3.

It has a diameter of 400 solar diameters. The secondary, which orbits every 3600 years, is a blue-green hued star of magnitude 5.4. Its common name means “the kneeler’s head”. Beta Herculis, also called Kornephoros, is the brightest star in Hercules. It is a yellow giant of magnitude 2.8, 148 light-years from Earth. Its traditional name means “club-bearer”. Delta Herculis is a double star divisible in small amateur telescopes. The primary is a blue-white star of magnitude 3.1, 78 light-years from Earth.

The optical companion is of magnitude 8.2. Gamma Herculis is also a double star divisible in small amateur telescopes. The primary is a white giant of magnitude 3.8, 195 light-years from Earth. The optical companion, widely separated, is 10th magnitude. Zeta Herculis is a binary star that is becoming divisible in medium-aperture amateur telescopes, as the components widen to their peak in 2025. The system, 35 light-years from Earth, has a period of 34.5 years. The primary is a yellow-tinged star of magnitude 2.9 and the secondary is an orange star of magnitude 5.7.

There are several dimmer variable stars in Hercules. 30 Herculis, also called g Herculis, is a semi-regularred giant with a period of 3 months. 361 light-years from Earth, it has a minimum magnitude of 6.3 and a maximum magnitude of 4.3. 68 Herculis, also called u Herculis, is a Beta Lyrae-typeeclipsing binary star. 865 light-years from Earth, it has a period of 2 days; its minimum magnitude is 5.4 and its maximum magnitude is 4.7.

hercules mythology image

Hercules is also home to many double stars and binary stars. Kappa Herculis is a double star divisible in small amateur telescopes. The primary is a yellow giant of magnitude 5.0, 388 light-years from Earth; the secondary is an orange giant of magnitude 6.3, 470 light-years from Earth. Rho Herculis is a binary star 402 light-years from Earth, divisible in small amateur telescopes. Both components are blue-green giant stars; the primary is magnitude 4.5 and the secondary is magnitude 5.5. 95 Herculis is a binary star divisible in small telescopes, 470 light-years from Earth. The primary is a silvery giant star of magnitude 4.9 and the secondary is an old giant star of magnitude 5.2. 100 Herculis is a double star easily divisible in small amateur telescopes. Both components are magnitude 5.8 blue-white stars; they are 165 and 230 light-years from Earth.

Mu Herculis is 27.4 light years from Earth. The solar apex, i.e., the point on the sky which marks the direction that the Sun is moving in its orbit around the center of the Milky Way, is located within Hercules, close to Vega in neighboring Lyra.

The constellation Corona Borealis

Mythology of the constellation Corona Borealis

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Corona Borealis

CORONA BOREALIS represents the crown or wreath worn by Ariadne, daughter of King Minos of Crete.

Her story is connected to that of the Minotaur – a creature half-man, half-bull, who dwelt on the island at the centre of a labyrinth with no known escape route.

Periodically, seven young men and seven girls were sent from Athens to be offered up to the Minotaur. One year, Theseus, heir to the throne of Athens, who had already proved himself a hero, volunteered to be one of the seven men in order that he might kill the Minotaur and thus prevent any further sacrifices.

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The Milky Way and 30 Constellations

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The Milky Way passes through parts of roughly 30 constellations.

The centre of the Galaxy lies in the direction of the constellation Sagittarius; it is here that the Milky Way is brightest. From Sagittarius, the hazy band of white light appears to pass westward to the Galactic anticenter in Auriga. The band then continues westward the rest of the way around the sky back to Sagittarius. The band divides the night sky into two roughly equal hemispheres.

The Galactic plane is inclined by about 60 degrees to the ecliptic (the plane of the Earth’s orbit). Relative to the celestial equator, it passes as far north as the constellation of Cassiopeia and as far south as the constellation of Crux, indicating the high inclination of Earth’s equatorial plane and the plane of the ecliptic relative to the Galactic plane.

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The north Galactic pole is situated at right ascension 12h 49m, declination +27.4° (B1950) near beta Comae Berenices, and the south Galactic pole is near alpha Sculptoris. Because of this high inclination, depending on the time of night and the year, the arc of Milky Way can appear relatively low or relatively high in the sky. For observers from about 65 degrees north to 65 degrees south on the Earth’s surface the Milky Way passes directly overhead twice a day.

Size and Composition of the Milky Way Galaxy

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A Panorama of the  Milky Way
360-degree panorama view of the Milky Way Galaxy (an assembled mosaic of photographs)

The Milky Way Size & Composition

The stellar disk of the Milky Way Galaxy is approximately 100,000 ly (30 kpc) in diameter, and is, on average, about 1,000 ly (0.3 kpc) thick. As a guide to the relative physical scale of the Milky Way, if it were reduced to 100 m (110 yd) in diameter, the Solar System, including the hypothesized Oort cloud, would be no more than 1 mm (0.04 in) in width, about the size of a grain of sand. The nearest star, Proxima Centauri, would be 4.2 mm (0.2 in) distant. Alternatively visualized, if the Solar System out to Pluto were the size of a US quarter (25 mm or 1.0 in in diameter), the Milky Way would have a diameter of 2,000 kilometers, an area approximately one-third the size of the United States.

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ColeyArtAstro-The Milky Way

The Milky Way contains at least 100 billion stars and may have up to 400 billion stars. The exact figure depends on the number of very low-mass, or dwarf stars, which are hard to detect, especially at distances of more than 300 ly (90 pc) from the Sun. As a comparison, the neighboring Andromeda Galaxy contains an estimated one trillion (1012) stars. Filling the space between the stars is a disk of gas and dust called the interstellar medium. This disk has at least a comparable extent in radius to the stars, while the thickness of the gas layer ranges from hundreds of light years for the colder gas to thousands of light years for warmer gas. Both gravitational microlensing and planetary transit observations indicate that there may be at least as many planets bound to stars as there are stars in the Milky Way, while microlensing measurements indicate that there are more rogue planets not bound to host stars than there are stars. The Milky Way Galaxy contains at least one planet per star, resulting in 100–400 billion planets, according to a January 2013 study of the five-planet star system Kepler-32 with the Kepler space observatory. A different January 2013 analysis of Kepler data estimated that at least 17 billion Earth-sized exoplanets reside in the Milky Way Galaxy. Such Earth-sized planets may be more numerous than gas giants. Besides exoplanets, “exocomets“, comets beyond the Solar System, have also been detected and may be common in the Milky Way Galaxy.

The disk of stars in the Milky Way does not have a sharp edge beyond which there are no stars. Rather, the concentration of stars drops smoothly with distance from the center of the Galaxy. Beyond a radius of roughly 40,000 ly (12 kpc), the number of stars per cubic parsec drops much faster with radius, for reasons that are not understood. Surrounding the Galactic disk is a spherical Galactic Halo of stars and globular clusters that extends further outward, but is limited in size by the orbits of two Milky Way satellites, the Large and the Small Magellanic Clouds, whose closest approach to the Galactic center is about 180,000 ly (55 kpc). At this distance or beyond, the orbits of most halo objects would be disrupted by the Magellanic Clouds. Hence, such objects would probably be ejected from the vicinity of the Milky Way. The integrated absolute visual magnitude of the Milky Way is estimated to be −20.9.

Estimates for the mass of the Milky Way vary, depending upon the method and data used. At the low end of the estimate range, the mass of the Milky Way is 5.8×1011 solar masses (M), somewhat smaller than the Andromeda Galaxy. Measurements using the Very Long Baseline Array in 2009 found velocities as large as 254 km/s for stars at the outer edge of the Milky Way. As the orbital velocity depends on the total mass inside the orbital radius, this suggests that the Milky Way is more massive, roughly equaling the mass of Andromeda Galaxy at 7×1011 M within 160,000 ly (49 kpc) of its center. A 2010 measurement of the radial velocity of halo stars finds the mass enclosed within 80 kiloparsecs is 7×1011 M☉. Most of the mass of the Galaxy appears to be matter of unknown form which interacts with other matter through gravitational but not electromagnetic forces; this is dubbed dark matter. A dark matter halo is spread out relatively uniformly to a distance beyond one hundred kiloparsecs from the Galactic Center. Mathematical models of the Milky Way suggest that the total mass of the entire Galaxy lies in the range 1–1.5×1012 M.

Aquila Constellation in Early September

The Aquila Constellation –  Seen with my Naked Eye

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Kite-Like Aquila – Naked eye view.

This Constellation is a bit like the shape of a kite. In early September, with a clear sky, even I have been able to see it through my window, in the early hours.

Once you locate Altair, brightest Star in this region, you will know you have found it.

 

Aquila is a constellation in the northern sky. Its name is Latin for ‘eagle’ and it represents the bird who carried Zeus’s/Jupiter’s thunderbolts in Greco-Roman mythology.

In classical Greek mythology, Aquila was identified as the eagle that carried the thunderbolts of Zeus. It was sent by him to carry the shepherd boy Ganymede, whom he desired, to Mount Olympus; the constellation of Aquarius is sometimes identified with Ganymede.

Aquila, with the now-obsolete figure of Antinous, as depicted by Sidney Hall in Urania’s Mirror, a set of constellation cards published in London c.1825. At left is Delphinus. According to Gavin White, the Babylonian Eagle carried the constellation called the Dead Man in its talons. The author also draws a comparison to the Classical stories of Antinous and Ganymede.

©Wikipedia

Aquila lies just a few degrees North of the celestial equator. The alpha star, Altair, is a vertex of the Summer Triangle asterism. The constellation is best seen in the summer as it is located along the Milky Way. Because of this location along the line of our galaxy, many clusters and nebulae are found within its borders, but they are dim and there are few galaxies.

 

Registry Cleaners Are Just Dangerous

Header - Reg Cleaner Danger

Registry cleaners have been used as a vehicle by a number of trojan applications to install malware, typically through social engineering attacks that use website popups or free downloads that falsely report problems that can be “rectified” by purchasing or downloading a registry cleaner.

The worst of the breed are products that advertise and encourage a “free” registry scan; however, the user typically finds the product has to be purchased for a substantial sum, before it will effect any of the anticipated “repairs”. Rogue registry cleaners “WinFixer” have been ranked as one of the most prevalent pieces of malware currently in circulation.

Scanners as Scareware

Rogue registry cleaners are often marketed with alarmist advertisements that falsely claim to have pre-analysed your PC, displaying bogus warnings to take “corrective” action; hence the descriptive label “Scareware”.

In October 2008, Microsoft and the Washington attorney general filed a lawsuit against two Texas firms, Branch Software and Alpha Red, producers of the “Registry Cleaner XP” scareware.

  The lawsuit alleges that the company sent incessant pop-ups resembling system warnings to consumers’ personal computers stating “CRITICAL ERROR MESSAGE! – REGISTRY DAMAGED AND CORRUPTED”, before instructing users to visit a web site to download Registry Cleaner XP at a cost of $39.99.

Undeletable registry keys

Most registry cleaners cannot repair scenarios such as undeletable registry keys caused by embedded null characters in their names; only specialized tools such as the RegDelNull utility (part of the free Sysinternals software) are able to do this.imagesCAKWY9S5

 Recovery capability limitations

A registry cleaner cannot repair a registry hive that cannot be mounted by the system, making the repair via “slave mounting” of a system disk impossible. A corrupt registry can be recovered in a number of ways that are supported by Microsoft (e.g. Automated System Recovery, from a “last known good” boot menu, by re-running setup or by using System Restore). “Last known good” restores the last system registry hive (containing driver and service configuration) that successfully booted the system.

Salute the Kernel

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Kernel

 

In computing, the kernel is a computer program that manages input/output requests from software and translates them into data processing instructions for the central processing unit and other electronic components of a computer. The kernel is a fundamental part of a modern computer’s operating system.

 

When a computer program (in this case called a process) makes requests of the kernel, the request is called a system call. Various kernel designs differ in how they manage system calls (time-sharing) and resources. For example, a monolithic kernel executes all the operating system instructions in the same address space to improve the performance of the system.

A microkernel runs most of the operating system’s background process in user space, to make the operating system more modular and, therefore, easier to maintain.

For computer programmers, the kernel’s interface is a low-level abstraction layer.

Edmund Halley

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Edmond Halley, FRS , 8 November 1656 – 14 January 1742) was an English astronomer, geophysicist, mathematician, meteorologist, and physicist who is best known for computing the orbit of the eponymous Halley’s Comet. He was the second Astronomer Royal in Britain, succeeding John Flamsteed.

Halley was born in Haggerston, Shoreditch, England. His father, Edmond Halley Sr., came from a Derbyshire family and was a wealthy soap-maker in London. As a child, Halley was very interested in mathematics. He studied at St Paul’s School, and from 1673 at The Queen’s College, Oxford. While an undergraduate, Halley published papers on the Solar System and sunspots.

On leaving Oxford, in 1676, Halley visited the south Atlantic island of Saint Helena and set up an observatory with a large sextant with telescopic sights to catalogue the stars of the southern hemisphere. While there he observed a transit of Mercury, and realised that a similar transit of Venus could be used to determine the absolute size of the Solar System. He returned to England in May 1678. In the following year he went to Danzig (Gdańsk) on behalf of the Royal Society to help resolve a dispute. Because astronomer Johannes  Hevelius did not use a telescope, his observations had been questioned by Robert Hooke. Halley stayed with Hevelius and he observed and verified the quality of Hevelius’ observations. The same year, Halley published the results from his observations on St. Helena as Catalogus Stellarum Australium which included details of 341 southern stars. These additions to present-day star maps earned him comparison with Tycho Brahe. Halley was awarded his M.A. degree at Oxford and elected as a Fellow of the Royal Society.

In 1686, Halley published the second part of the results from his Helenian expedition, being a paper and chart on trade winds and monsoons. In this he identified solar heating as the cause of atmospheric motions. He also established the relationship between barometric pressure and height above sea level. His charts were an important contribution to the emerging field of information visualization.

Halley married Mary Tooke in 1682 and settled in Islington. The couple had three children. He spent most of his time on lunar observations, but was also interested in the problems of gravity. One problem that attracted his attention was the proof of Kepler’s laws of planetary motion. In August 1684, he went to Cambridge to discuss this with Sir Isaac Newton, only to find that Newton had solved the problem, but published nothing. Halley convinced him to write the Philosophiæ Naturalis Principia Mathematica (1687), which was published at Halley’s expense.

In 1691, Halley built a diving bell, a device in which the atmosphere was replenished by way of weighted barrels of air sent down from the surface. In a demonstration, Halley and five companions dived to 60 feet (18 m) in the River Thames, and remained there for over an hour and a half. Halley’s bell was of little use for practical salvage work, as it was very heavy, but he made improvements to it over time, later extending his underwater exposure time to over 4 hours. Halley suffered one of the earliest recorded cases of middle ear barotrauma. That same year, at a meeting of the Royal Society, Halley introduced a rudimentary working model of a magnetic compass using a liquid-filled housing to damp the swing and wobble of the magnetized needle.

In 1691 Halley sought the post of Savilian Professor of Astronomy at Oxford, but, due to his well-known atheism, was opposed by the Archbishop of Canterbury, John Tillotson and Bishop Stillingfleet. The post went instead to David Gregory, who had the support of Isaac Newton

In 1692, Halley put forth the idea of a hollow Earth consisting of a shell about 500 miles (800 km) thick, two inner concentric shells and an innermost core, about the diameters of the planets Venus, Mars, and Mercury. He suggested that atmospheres separated these shells, and that each shell had its own magnetic poles, with each sphere rotating at a different speed. Halley proposed this scheme in order to explain anomalous compass readings. He envisaged each inner region as having an atmosphere and being luminous (and possibly inhabited), and speculated that escaping gas caused the Aurora Borealis.

In 1693 Halley published an article on life annuities, which featured an analysis of age-at-death on the basis of the Breslau statistics Caspar Neumann had been able to provide. This article allowed the British government to sell life annuities at an appropriate price based on the age of the purchaser. Halley’s work strongly influenced the development of actuarial science. The construction of the life-table for Breslau, which followed more primitive work by John Graunt, is now seen as a major event in the history of demography.

By 1706 Halley had learned Arabic and completed the translation started by Edward Bernard of Books V-VII of Apollonius‘s Conics from copies found at Leiden and the Bodleian Library at Oxford. He also completed a new translation of the first four books from the original Greek that had been started by the late David Gregory. He published these along with his own reconstruction of Book VIII  in the first complete Latin edition in 1710.

Exploration

In 1698, Halley was given the command of the Paramour, a 52 feet (16 m) pink, so that he could carry out investigations in the South Atlantic into the laws governing the variation of the compass. On 19 August 1698, he took command of the ship and, in November 1698, sailed on what was the first purely scientific voyage by an English naval vessel. Unfortunately problems of insubordination arose over questions of Halley’s competence to command a vessel. Halley returned the ship to England to proceed against officers in July 1699. The result was a mild rebuke for his men, and dissatisfaction for Halley, who felt the court had been too lenient. Halley thereafter received a temporary commission as a Captain in the Royal Navy, recommissioned the Paramour on 24 August 1699 and sailed again in September 1699 to make extensive observations on the conditions of terrestrial magnetism. This task he accomplished in a second Atlantic voyage which lasted until 6 September 1700, and extended from 52 degrees north to 52 degrees south. The results were published in General Chart of the Variation of the Compass (1701). This was the first such chart to be published and the first on which isogonic, or Halleyan, lines appeared.

In November 1703, Halley was appointed Savilian Professor of Geometry at the University of Oxford, his theological enemies, John Tillotson and Bishop Stillingfleet having died, and received an honorary degree of doctor of laws in 1710. In 1705, applying historical astronomy methods, he published Synopsis Astronomia Cometicae, which stated his belief that the comet sightings of 1456, 1531, 1607, and 1682 related to the same comet, which he predicted would return in 1758. Halley did not live to witness the comet’s return, but when it did, the comet became generally known as Halley’s Comet.

In 1716, Halley suggested a high-precision measurement of the distance between the Earth and the Sun by timing the transit of Venus. In doing so, he was following the method described by James Gregory in Optica Promota (in which the design of the Gregorian telescope is also described). It is reasonable to assume Halley possessed and had read this book given that the Gregorian design was the principal telescope design used in astronomy in Halley’s day. It is not to Halley’s credit that he failed to acknowledge Gregory’s priority in this matter. In 1718 he discovered the proper motion of the “fixed” stars by comparing his astrometric measurements with those given in Ptolemy’s Almagest. Arcturus and Sirius were two noted to have moved significantly, the latter having progressed 30 arc minutes (about the diameter of the moon) southwards in 1800 years.

In 1720, together with his friend the antiquarianWilliam Stukeley, Halley participated in the first attempt to scientifically date Stonehenge. Assuming that the monument had been laid out using a magnetic compass, Stukeley and Halley attempted to calculate the perceived deviation introducing corrections from existing magnetic records, and suggested three dates (AD 920, AD 220 and 460 BC), the earliest being the one accepted. These dates were wrong by thousands of years, but the idea that scientific methods could be used to date ancient monuments was revolutionary in its day.

Halley succeeded John Flamsteed in 1720 as Astronomer Royal, a position Halley held until his death in 1742 at the age of 85. Halley was buried in the graveyard of the old church of St. Margaret (since rebuilt), at Lee, South London. He was interred in the same vault as Astronomer Royal John Pond; the unmarked grave of Astronomer Royal Nathaniel Bliss is nearby.

 

 

The new language for all is HTML5

HTML5 Is Now Gaining Ground in 2013

 

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This Is Coley-Art-Astro – Icon Head

HTML5 is a mark-up language used for structuring and presenting content for the World Wide Web and a core technology of the Internet. It is the fifth revision of the HTML standard (created in 1990 and standardized as HTML 4 as of 1997) and, as of December 2012, is a candidate recommendation of the World Wide Web Consortium (W3C). Its core aims have been to improve the language with support for the latest multimedia while keeping it easily readable by humans and consistently understood by computers and devices (web browsers, parsers, etc.). HTML5 is intended to subsume not only HTML 4, but also XHTML 1 and DOM Level 2 HTML.

Following its immediate predecessors HTML 4.01 and XHTML 1.1, HTML5 is a response to the fact that the HTML and XHTML in common use on the World Wide Web are a mixture of features introduced by various specifications, along with those introduced by software products such as web browsers, those established by common practice, and the many syntax errors in existing web documents.

 

It is also an attempt to define a single markup language that can be written in either HTML or XHTML syntax. It includes detailed processing models to encourage more interoperable implementations; it extends, improves and rationalises the markup available for documents, and introduces mark-up and application programming interfaces (APIs) for complex web applications. For the same reasons, HTML5 is also a potential candidate for cross-platform mobile applications. Many features of HTML5 have been built with the consideration of being able to run on low-powered devices such as smartphones and tablets. In December 2011, research firm Strategy Analytics forecast sales of HTML5 compatible phones will top 1 billion in 2013.

In particular, HTML5 adds many new syntactic features. These include the new <video>, <audio> and <canvas>elements, as well as the integration of scalable vector graphics (SVG) content (that replaces the uses of generic <object> tags) and MathML for mathematical formulas. These features are designed to make it easy to include and handle multimedia and graphical content on the web without having to resort to proprietary plugins and APIs. Other new elements, such as <section>, <article>, <header> and <nav>, are designed to enrich the semantic content of documents.

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New attributes have been introduced for the same purpose, while some elements and attributes have been removed. Some elements, such as <a>, <cite> and <menu> have been changed, redefined or standardized. The APIs and Document Object Model (DOM) are no longer afterthoughts, but are fundamental parts of the HTML5 specification. HTML5 also defines in some detail the required processing for invalid documents so that syntax errors will be treated uniformly by all conforming browsers and other user agents.

Keep the Internet Free for All

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How to help keep the Net Free

Net neutrality (also network neutrality or Internet neutrality) is the principle that Internet service providers and governments should treat all data on the Internet equally, not discriminating or charging differentially by user, content, site, platform, application, type of attached equipment, and modes of communication.

“….IP address blocking prevents the connection between a server or website and certain IP addresses or ranges of addresses. IP address blocking effectively bans undesired connections from hosts using affected addresses to a website, mail server, or other Internet server….”

Join my group on Facebook, Stop2tiernet

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No Snoopers Charter Campaign

There has been extensive debate about whether net neutrality should be required by law. Since the early 2000s, advocates of net neutrality and associated rules have raised concerns about the ability of broadband providers to use their last mile infrastructure to block Internet applications and content (e.g. websites, services, and protocols), and even block out competitors.

(The term “net neutrality” didn’t come into popular use until several years later, however.) The possibility of regulations designed to mandate the neutrality of the Internet has been subject to fierce debate, especially in the United States.

Port Blocking

Port blocking includes the deliberate decision by ISPs to deny onward transmission of traffic, or delivery of traffic, to an intended recipient. ISPs do not have a legitimate reason to deny onward packet transmission to specific customers of other ISPs. The ISPs have contractually committed to carry any and all packets from the former ISP without regard for the identity and marketplace success of that ISP’s customers (on a first-come, first-served basis).

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Blog for Amnesty - Protect the Human

Meteor Shower- It was God that Started It

God, The Religious Lot try to Claim Everything.

The Meteor Showers – were not sacred in His eyes. It was an Act of God. Any Doomsday bad news is How Human Beings deal with the situation. Anything like the Shooting Stars is not nature, its the work of God. I’m not saying we make things up to suit ourselves or anything…of course.

Many bloggers claimed God was responsible for the Firework Show that is the Periseids.

 

What is the Matter with Matter

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Matter – The term has often been used in reference to a substance (often a particle) that has rest mass. Matter is also used loosely as a general term for the substance that makes up all observable physical objects.

Matter should not be confused with mass, as the two are not quite the same in modern physics. For example, mass is a conserved quantity, which means that its value is unchanging through time, within closed systems. However, matter is not conserved in such systems, although this is not obvious in ordinary conditions on Earth, where matter is approximately conserved.

Still, special relativity shows that matter may disappear by conversion into energy, even inside closed systems, and it can also be created from energy, within such systems.

However, because mass (like energy) can neither be created nor destroyed, the quantity of mass and the quantity of energy remain the same during a transformation of matter (which represents a certain amount of energy) into non-material (i.e., non-matter) energy. This is also true in the reverse transformation of energy into matter.

All objects we see with the naked eye are composed of atoms. This atomic matter is in turn made up of interacting subatomic particles—usually a nucleus of protons and neutrons, and a cloud of orbiting electrons. Typically, science considers these composite particles matter because they have both rest mass and volume. By contrast, massless particles, such as photons, are not considered matter, because they have neither rest mass nor volume.

However, not all particles with rest mass have a classical volume, since fundamental particles such as quarks and leptons (sometimes equated with matter) are considered “point particles” with no effective size or volume. Nevertheless, quarks and leptons together make up “ordinary matter,” and their interactions contribute to the effective volume of the composite particles that make up ordinary matter.

Matter commonly exists in four states (or phases): solid, liquid and gas, and plasma. . However, advances in experimental techniques have revealed other previously theoretical phases, such as Bose–Einstein condensates and fermionic condensates.

A focus on an elementary-particle view of matter also leads to new phases of matter, such as the quark–gluon plasma. For much of the history of the natural sciences people have contemplated the exact nature of matter. The idea that matter was built of discrete building blocks, the so-called particulate theory of matter, was first put forward by the Greek philosophers Leucippus (~490 BC) and Democritus (~470–380 BC).

Albert Einstein showed that ultimately all matter is capable of being converted to energy (known as mass-energy equivalence) by the famous formula E = mc2, where E is the energy of a piece of matter of mass m, times c2 the speed of light squared. As the speed of light is 299,792,458 metres per second (186,282 mi/s), a relatively small amount of matter may be converted to a large amount of energy. An example is that positrons and electrons (matter) may transform into photons (non-matter). However, although matter may be created or destroyed in such processes, neither the quantity of mass or energy change during the process.

 

 

How To Measure The Age Of The Milky Way

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The ages of individual stars in the Milky Way can be estimated by measuring the abundance of long-lived radioactive elements such as thorium-232 and uranium-238, then comparing the results to estimates of their original abundance, a technique called nucleocosmochronology. These yield values of about 12.5 ± 3 billion years (Ga) for CS 31082- 001and 13.8 ± 4 billion years for BD+17° 3248.

Once a white dwarf star is formed, it begins to undergo radiative cooling and the surface temperature steadily drops. By measuring the temperatures of the coolest of these white dwarfs and comparing them to their expected initial temperature, an age estimate can be made. With this technique, the age of the globular cluster M4 was estimated as12.7 ± 0.7 billion years.

Hubble : Beyond the Milky Way
Beyond the Milky Way

Globular clusters are among the oldest objects in the Milky Way Galaxy, which thus set a lower limit on the age of the galaxy. Age estimates of the oldest of these clusters gives a best fit estimate of 12.6 billion years, and a 95% confidence upper limit of 16 billion years. In 2007, a star in the galactic halo, HE 1523-0901, was estimated to be about 13.2 billion years old, ?0.5 billion years less than the age of the universe.

As the oldest known object in the Milky Way at that time, this measurement placed a lower limit on the age of the Milky Way. This estimate was determined using the UV-Visual Echelle Spectrograph of the Very Large Telescope to measure the relative strengths of spectral lines caused by the presence of thorium and other elements created by the R-process.

The line strengths yield abundances of different elemental isotopes, from which an estimate of the age of the star can be derived using nucleocosmochronology.

Spiral Arms – Milky Way

Two Spiral Arms

The Scutum–Centaurus arm and the Carina–Sagittarius arm, have tangent points inside the Sun’s orbit about the centre of the Milky Way. If these arms contain an over density of stars compared to the average density of stars in the Galactic disk, it would be detectable by counting the stars near the tangent point.

Spiral Arms - Arch - Milky way
Arch – Milky way

 

Outside the gravitational influence of the Galactic bars, astronomers generally organize the interstellar medium and stars in the disk of the Milky Way into four spiral arms.

All of these arms contain more interstellar gas and dust than the Galactic average as well as a high concentration of star formation, traced by H II regions and molecular clouds. Counts of stars in near infrared light indicate that two arms contain approximately 30% more red giant stars than would be expected in the absence of a spiral arm, while two contain no more red giant stars than regions outside of arms.

Long image - Milky Way center
We Are Here – Milky Way

Maps of the Milky Way’s spiral structure are notoriously uncertain and exhibit striking differences. Some 150 years after Alexander (1852) first suggested that the Milky Way was a spiral, there is currently no consensus on the nature of the Galaxy’s spiral arms.

Perfect logarithmic spiral patterns ineptly describe features near the Sun, namely since galaxies commonly exhibit arms that branch, merge, twist unexpectedly, and feature a degree of irregularity. The possible scenario of the Sun within a spur / Local arm emphasizes that point and indicates that such features are probably not unique, and exist elsewhere in the Galaxy.

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Amazing Milky Way

As in most spiral galaxies, each spiral arm can be described as a logarithmic spiral. Estimates of the pitch angle of the arms range from ?7° to ?25°. Until recently, there were thought to be four major spiral arms which all start near the Galaxy’s centre.

A short explanation of the Atom

The atom is a basic unit of matter that consists of a dense central nucleus surrounded by a cloud of negatively charged electrons. The atomic nucleus contains a mix of positively charged protons and electrically neutral neutrons (except in the case of hydrogen-1, which is the only stable nuclide with no neutrons).

Atoms
Atoms in Coleyartastro

The electrons of an atom are bound to the nucleus by the electromagnetic force. Likewise, a group of atoms can remain bound to each other by chemical bonds based on the same force, forming a molecule. An atom containing an equal number of protons and electrons is electrically neutral, otherwise it is positively or negatively charged and is known as an ion. An atom is classified according to the number of protons and neutrons in its nucleus: the number of protons determines the chemical element, and the number of neutrons determines the isotope of the element.

Chemical atoms, which in science now carry the simple name of “atom,” are minuscule objects with diameters of a few tenths of a nanometer and tiny masses proportional to the volume implied by these dimensions. Atoms can only be observed individually using special instruments such as the scanning tunneling microscope. Over 99.94% of an atom’s mass is concentrated in the nucleus, with protons and neutrons having roughly equal mass.

Each element has at least one isotope with an unstable nucleus that can undergo radioactive decay. This can result in a transmutation that changes the number of protons or neutrons in a nucleus. Electrons that are bound to atoms possess a set of stable energy levels, or orbitals, and can undergo transitions between them by absorbing or emitting photons that match the energy differences between the levels. The electrons determine the chemical properties of an element, and strongly influence an atom’s magnetic properties. The principles of quantum mechanics have been successfully used to model the observed properties of the atom.

This Is Canis Minor

The Lesser Dog – is a small constellation in the northern celestial hemisphere. In the second century, it was included as an asterism, or pattern, of two stars in Ptolemy‘s 48 constellations, and it is counted among the 88 modern constellations. Its name is Latin for “lesser dog”, in contrast to Canis Major, the “greater dog”; both figures are commonly represented as following the constellation of Orion the hunter.

canis-minor in sky-map

Canis Minor contains only two stars brighter than the fourth magnitude, Procyon (Alpha Canis Minoris), with a magnitude of 0.34, and Gomeisa (Beta Canis Minoris), with a magnitude of 2.9. The constellation’s dimmer stars were noted by Johann Bayer, who named eight stars including Alpha and Beta, and John Flamsteed, who numbered fourteen. Procyon is the seventh-brightest star in the night sky, as well as one of the closest. A yellow-white main sequence star, it has a white dwarf companion. Gomeisa is a blue-white main sequence star. Luyten’s Star is a ninth-magnitude red dwarf and the Solar System‘s next closest stellar neighbour in the constellation after Procyon. The fourth-magnitude HD 66141, which has evolved into an orange giant towards the end of its life cycle, was discovered to have a planet in 2012. There are two faint deep sky objects within the constellation’s borders. The 11 Canis-Minorids are a meteor shower that can be seen in early December.

History and mythology

Though strongly associated with the Classical Greek uranographic tradition, Canis Minor originates from ancient Mesopotamia. Procyon and Gomeisa were called MASH.TAB.BA or “twins” in the Three Stars Each tablets, dating to around 1100 BC. In the later MUL.APIN, this name was also applied to the pairs of Pi3 and Pi4 Orionis and Zeta and Xi Orionis. The meaning of MASH.TAB.BA evolved as well, becoming the twin deities Lulal and Latarak, who are on the opposite side of the sky from Papsukal, the True Shepherd of Heaven in Babylonian mythology. Canis Minor was also given the name DAR.LUGAL, which translates to “the star which stands behind it”, in the MUL.APIN; the constellation represents a rooster. This name may have also referred to the constellation Lepus. DAR.LUGAL was also denoted DAR.MUŠEN and DAR.LUGAL.MUŠEN in Babylonia. Canis Minor was then called tarlugallu in Akkadian astronomy.

Canis Minor was one of the original 48 constellations formulated by Ptolemy in his second-century Almagest, in which it was defined as a specific pattern (asterism) of stars; Ptolemy identified only two stars and hence no depiction was possible. The Ancient Greeks called the constellation προκυων/Procyon, “coming before the dog”, transliterated into Latin as Antecanis, Praecanis, or variations thereof, by Cicero and others. Roman writers also appended the descriptors parvus, minor or minusculus (“small” or “lesser”, for its faintness), septentrionalis (“northerly”, for its position in relation to Canis Major), primus (rising “first”) or sinister (rising to the “left”) to its name Canis. In Greek mythology, Canis Minor was sometimes connected with the Teumessian Fox, a beast turned into stone with its hunter, Laelaps, by Zeus, who placed them in heaven as Canis Major (Laelaps) and Canis Minor (Teumessian Fox). Eratosthenes accompanied the Little Dog with Orion, while Hyginus linked the constellation with Maera, a dog owned by Icarius of Athens. On discovering the latter’s death, the dog and Icarius’ daughter Erigone took their lives and all three were placed in the sky—Erigone as Virgo and Icarius as Boötes. As a reward for his faithfulness, the dog was placed along the “banks” of the Milky Way, which the ancients believed to be a heavenly river, where he would never suffer from thirst.

The medieval Arabic astronomers maintained the depiction of Canis Minor (al-Kalb al-Asghar in Arabic) as a dog; in his Book of the Fixed Stars, Abd al-Rahman al-Sufi included a diagram of the constellation with a canine figure superimposed. There was one slight difference between the Ptolemaic vision of Canis Minor and the Arabic; al-Sufi claims Mirzam, now assigned to Orion, as part of both Canis Minor—the collar of the dog—and its modern home. The Arabic names for both Procyon and Gomeisa alluded to their proximity and resemblance to Sirius, though they were not direct translations of the Greek; Procyon was called ash-Shi’ra ash-Shamiya, the “Syrian Sirius” and Gomeisa was called ash-Shira al-Ghamisa, the Sirius with bleary eyes. Among the Merazig of Tunisia, shepherds note six constellations that mark the passage of the dry, hot season. One of them, called Merzem, includes the stars of Canis Minor and Canis Major and is the herald of two weeks of hot weather.

The ancient Egyptians thought of this constellation as Anubis, the jackal god.

Alternative names have been proposed: Johann Bayer in the early 17th century termed the constellation Fovea “The Pit”, and MorusSycamine Tree”. Seventeenth-century German poet and author Philippus Caesius linked it to the dog of Tobias from the Apocrypha. Richard A. Proctor gave the constellation the name Felis “the Cat” in 1870 (contrasting with Canis Major, which he had abbreviated to Canis “the Dog”), explaining that he sought to shorten the constellation names to make them more manageable on celestial charts. Occasionally, Canis Minor is confused with Canis Major and given the name Canis Orionis (“Orion’s Dog”)

The Dolphin (Delphinus) Constellation

delphinus in sky-map
Dolphin

Delphinus is a constellation in the northern sky, close to the celestial equator. Its name is Latin for dolphin. Delphinus was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and it remains among the 88 modern constellations recognized by the International Astronomical Union. It is one of the smaller constellations, ranked 69th in size.

Delphinus’ brightest stars form a distinctive asterism that can easily be recognized. It is bordered (clockwise from north) by Vulpecula the fox, Sagitta the arrow, Aquila the eagle, Aquarius the water-carrier, Equuleus the foal and Pegasus the flying horse.

Stars

Delphinus does not have any bright stars; its brightest star is of magnitude 3.8. The main asterism in Delphinus is Job’s Coffin, formed from the four brightest stars: Alpha, Beta, Gamma, and Delta Delphini. Alpha and Beta Delphini are named Sualocin and Rotanev, respectively. When read backwards, they read as Nicolaus Venator, the Latinized name of Palermo Observatory‘s former director, Niccolò Cacciatore. However, Delphinus is in a rich Milky Way star field.

Alpha Delphini, called Sualocin, is a blue-white hued main sequence star of magnitude 3.8, 241 light-years from Earth. Beta Delphini, called Rotanev, is a close binary star and the brightest in Delphinus, divisible in only large amateur telescopes. To the unaided eye, it appears to be a white star of magnitude 3.6. It has a period of 27 years and is 97 light-years from Earth. Gamma Delphini is a celebrated binary star among amateur astronomers. The primary is a gold-colored star of magnitude 4.3 and the secondary is a yellow-tinged star of magnitude 5.1. 102 light-years away, the components of Gamma Delphini are divisible in a small amateur telescope. The secondary, also described as green, is 10 arcseconds from the primary. Struve 2725, called the “Ghost Double”, is a pair that appears similar to a dimmer Gamma Delphini. Its components of magnitudes 7.6 and 8.4 are separated by 6 arcseconds and are 15 arcminutes from Gamma Delphini itself.

There are several dimmer stars in Delphinus. Delta Delphini is a type A7 IIIp star of magnitude 4.43. Epsilon Delphini, called Deneb Dulfim, meaning “tail of the Dolphin”, is a star of spectral class B6 III and magnitude 4.

Delphinus is also home to several variable stars. R Delphini is a Mira-type variable star with a period of 285.5 days. Its magnitude ranges between a maximum of 7.6 and a minimum of 13.8.

Rho Aquilae moved across the border into Delphinus in 1992.

HR Delphini was a nova that brightened to magnitude 3.5 in December 1967. On 14 August 2013, a possible nova was discovered by amateur astronomer Koichi Itagaki, initially labelled PNV J20233073+2046041, now labelled Nova Delphini 2013.

Deep-sky objects

Because it is in a rich Milky Way star field, Delphinus has several deep-sky objects. NGC 6891 is a planetary nebula of magnitude 10.5. NGC 6934 is a globular cluster of magnitude 9.75. At a distance of about 185,000 light-years, the globular cluster NGC 7006 is extremely remote. It is also fairly dim at magnitude 11.5.

 

Immanuel Kant

Immanuel Kant (22 April 1724 – 12 February 1804) was a German philosopher who is widely considered to be a central figure of modern philosophy. He argued that fundamental concepts structure human experience, and that reason is the source of morality. His thought continues to have a major influence in contemporary thought, especially the fields of metaphysics, epistemology, ethics, political philosophy, and aesthetics.

Kant’s major work, the Critique of Pure Reason (Kritik der reinen Vernunft, 1781), aimed to explain the relationship between reason and human experience. With this project, he hoped to move beyond what he took to be failures of traditional philosophy and metaphysics. He attempted to put an end to what he considered an era of futile and speculative theories of human experience, while resisting the skepticism of thinkers such as David Hume.

Kant argued that our experiences are structured by necessary features of our minds. In his view, the mind shapes and structures experience so that, on an abstract level, all human experience shares certain essential structural features. Among other things, Kant believed that the concepts of space and time are integral to all human experience, as are our concepts of cause and effect. One important consequence of this view is that one never has direct experience of things, the so-called noumenal world, and that what we do experience is the phenomenal world as conveyed by our senses. These claims summarize Kant’s views upon the subject–object problem. Kant published other important works on ethics, religion, law, aesthetics, astronomy, and history. These included the Critique of Practical Reason (Kritik der praktischen Vernunft, 1788), the Metaphysics of Morals (Die Metaphysik der Sitten, 1797), which dealt with ethics, and the Critique of Judgment (Kritik der Urteilskraft, 1790), which looks at aesthetics and teleology.

Kant aimed to resolve disputes between empirical and rationalist approaches. The former asserted that all knowledge comes through experience; the latter maintained that reason and innate ideas were prior. Kant argued that experience is purely subjective without first being processed by pure reason. He also said that using reason without applying it to experience only leads to theoretical illusions. The free and proper exercise of reason by the individual was a theme both of the Age of Enlightenment, and of Kant’s approaches to the various problems of philosophy. His ideas influenced many thinkers in Germany during his lifetime, and he moved philosophy beyond the debate between the rationalists and empiricists. Kant is seen as a major figure in the history and development of philosophy.

arty_colayartastro_planetarynebula
Nebula (planetary)

 

Nebular hypothesis

The nebular hypothesis is the most widely accepted model in the field of cosmogony to explain the formation and evolution of the Solar System. It suggests that the Solar System formed from nebulous material in space. There is evidence that it was first proposed in 1734 by Emanuel Swedenborg. Originally applied to our own Solar System, this process of planetary system formation is now thought to be at work throughout the universe. The widely accepted modern variant of the nebular hypothesis is the solar nebular disk model (SNDM) or simply solar nebular model. This nebular hypothesis offered explanations for a variety of properties of the Solar System, including the nearly circular and coplanar orbits of the planets, and their motion in the same direction as the Sun’s rotation. Some elements of the nebular hypothesis are echoed in modern theories of planetary formation, but most elements have been superseded.

According to the nebular hypothesis, stars form in massive and dense clouds of molecular hydrogengiant molecular clouds (GMC). They are gravitationally unstable, and matter coalesces within them to smaller denser clumps, which then rotate, collapse, and form stars. Star formation is a complex process, which always produces a gaseous protoplanetary disk around the young star. This may give birth to planets in certain circumstances, which are not well known. Thus the formation of planetary systems is thought to be a natural result of star formation. A sun-like star usually takes approximately 1 million years to form, with the protoplanetary disk evolving into a planetary system over the next 10-100 million years.

The protoplanetary disk is an accretion disk that feeds the central star. Initially very hot, the disk later cools in what is known as the T tauri star stage; here, formation of small dust grains made of rocks and ice is possible. The grains eventually may coagulate into kilometer-sized planetesimals. If the disk is massive enough, the runaway accretions begin, resulting in the rapid—100,000 to 300,000 years—formation of Moon- to Mars-sized planetary embryos. Near the star, the planetary embryos go through a stage of violent mergers, producing a few terrestrial planets. The last stage takes approximately 100 million to a billion years.

The formation of giant planets is a more complicated process. It is thought to occur beyond the so-called frost line, where planetary embryos mainly are made of various types of ice. As a result they are several times more massive than in the inner part of the protoplanetary disk. What follows after the embryo formation is not completely clear. Some embryos appear to continue to grow and eventually reach 5–10 Earth masses—the threshold value, which is necessary to begin accretion of the hydrogenhelium gas from the disk. The accumulation of gas by the core is initially a slow process, which continues for several million years, but after the forming protoplanet reaches about 30 Earth masses it accelerates and proceeds in a runaway manner. Jupiter- and Saturn-like planets are thought to accumulate the bulk of their mass during only 10,000 years. The accretion stops when the gas is exhausted. The formed planets can migrate over long distances during or after their formation. Ice giants such as Uranus and Neptune are thought to be failed cores, which formed too late when the disk had almost disappeared.

History

There is evidence that the nebular hypothesis was first proposed in 1734 by Emanuel Swedenborg. Immanuel Kant, who was familiar with Swedenborg’s work, developed the theory further in 1755, when Kant published his Universal Natural History and Theory of the Heavens, wherein he argued that gaseous clouds, nebulae, slowly rotate, gradually collapse and flatten due to gravity, eventually forming stars and planets.

A similar model was developed independently and proposed in 1796 by Pierre-Simon Laplace. in his Exposition du systeme du monde. He envisioned that the Sun originally had an extended hot atmosphere throughout the volume of the Solar System. His theory featured a contracting and cooling protosolar cloud—the protosolar nebula. As this cooled and contracted, it flattened and spun more rapidly, throwing off (or shedding) a series of gaseous rings of material; and according to him, the planets condensed from this material. His model was similar to Kant’s, except more detailed and on a smaller scale. While the Laplacian nebular model dominated in the 19th century, it encountered a number of difficulties. The main problem was angular momentum distribution between the Sun and planets. The planets have 99% of the angular momentum, and this fact could not be explained by the nebular model. As a result this theory of planet formation was largely abandoned at the beginning of the 20th century.

The fall of the Laplacian model stimulated scientists to find a replacement for it. During the 20th century many theories were proposed including the planetesimal theory of Thomas Chamberlin and Forest Moulton (1901), tidal model of Jeans (1917), accretion model of Otto Schmidt (1944), protoplanet theory of William McCrea (1960) and finally capture theory of Michael Woolfson. In 1978 Andrew Prentice resurrected the initial Laplacian ideas about planet formation and developed the modern Laplacian theory. None of these attempts was completely successful and many of the proposed theories were descriptive.

The birth of the modern widely accepted theory of planetary formation—the solar nebular disk model (SNDM)—can be traced to the Soviet astronomer Victor Safronov. His book Evolution of the protoplanetary cloud and formation of the Earth and the planets, which was translated to English in 1972, had a long lasting effect on the way scientists think about the formation of the planets. In this book almost all major problems of the planetary formation process were formulated and some of them solved. Safronov’s ideas were further developed in the works of George Wetherill, who discovered runaway accretion. While originally applied only to our own Solar System, the SNDM was subsequently thought by theorists to be at work throughout the universe; as of 12 September 2014, 1822 extrasolar planets have since been discovered in our galaxy.