Jagpal Singh June 2013 ~ All About Astronomy

Sunday 30 June 2013

Space - From Earth to the Edge of the Universe

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  • Hardcover: 360 pages
  • Publisher: DK Publishing (October 4, 2010)
  • Language: English
Featuring a wealth of incredible astronomical photographs, Space is perfect for anyone interested in astronomy, space imagery, and the history of space exploration. Space takes us on an imaginary journey that starts on a launch pad, goes toward the center of our Solar System to see the inner planets and the Sun, and then flies outward past the outer planets and on to the fringes of the Solar System.

Space – From Earth to the Edge of the Universe by editors Carole Stott, Robert Dinwiddie, David Hughes and Giles Sparrow; Dorling Kindersley(DK) Publishing; New York, New York; $40.00 (hard cover); 2010.

Space is big…but so is this large format book. This is a captivating and nicely packaged volume that includes a wealth of space exploration and astronomical imagery.

The editors and senior art editors and designers clearly worked together here to pull together a picture-perfect look at the origins of human space exploits, current status, and the unknown unknowns awaiting discovery and investigation within the Universe at large.

Just the table of contents gives you an eyeful that will set you page turning. From launch pad Earth and our neighboring worlds to beyond the asteroid belt into a galaxy of stars and a universe of galaxies to the outer limits.

One thing that truly stands out in this book is not only how much exploration has been started, but also how much is ahead of us.

Right up front, the reader will find a quote from Stephen Hawking, world renowned cosmologist: “I don’t think the human race will survive the next thousand years, unless we spread into space.”

This volume will help you book your travel plans, be it to the Moon or Mars – or to help satisfy your hunger for deep space travel.

This over 350-page book comes complete with a very generous reference section and glossary.
But the real eye-catching value of this work is the layout and explanatory graphics and text. It’s laden with descriptive artwork that provides expert and novice alike a new appreciation for the complexities of astronomical surveys and human and robotic space exploration.
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Saturday 29 June 2013

Astronomy for Entertainment (by Yakov Perelman)

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Astronomy for Entertainment (by Yakov Perelman)

Astronomy is a fortunate science; it needs no embellishments, said the French savant Arago. So fascinating are its achievements that no special effort is needed to attract attention. Nonetheless, the science of the heavens is not only a collection of astonishing revelations and daring theories. Ordinary facts, things that happen, day by day, are its substance. Most laymen have, generally speaking, a rather hazy notion of this prosaic aspect of astronomy. They find it of little interest, for it is indeed hard to concentrate on what is always before the eye.

Everyday happenings in the sky are the contents of this book, free from professional terminology with easy reading. Its purpose is to initiate the reader into the basic facts of astronomy. Ordinary facts with which you may be acquainted are couched here in unexpected paradoxes, or slanted from an odd and unexpected angle solely to excite the imagination and quicken your interest. The daily aspect of the science of the skies, its beginnings, not later findings that mainly form the contents of Astronomy for Entertainment. The purpose of the book is to initiate the reader into the basic facts of astronomy. Ordinary facts with which you may be acquainted are couched here in unexpected paradoxes, or slanted from an odd and unexpected angle. The theme is, as far as possible, free from "terminology" and technical paraphernalia that so often make the reader shy of books on astronomy.

Books on popular science are often rebuked for not being sufficiently serious. In a way the rebuke is just, and support for it can be found (if one has in mind the exact natural sciences) in the tendency to avoid calculations in any shape or form. And yet the reader can really master his subject only by learing how to reckon, even though in a rudimentary fashion. Hence, both in Astronomy for Entertainment and in other books of this series, the aurhor has not attempted to avoid the simplest of calculations. True, he has taken care to present them in an easy form, well within the reach of all who have studied mathematics at school. It is his conviction that these exercises help not only retain the knowledge acquired; they are also a useful introduction to more serious reading.

This book contains chapters relating to the Earth, the Moon, planets, stars and gravitation. The author has concentated in the main on materials not usually discussed in works of this nature. Subjects omitted in the present book, will, he hopes, be treated in a second volume. The book, it should be said, makes no attempt to analyze in detail the rich content of modern astronomy.

Unfortunately Y. Perelman never wrote the continuation he had planned for this book, as untimely death in warbound Leningrad in 1942 interruped his labours.

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Tuesday 18 June 2013

Clown Face Nebula (Eskimo Nebula)

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Eskimo Nebula


A planetary nebula, also known as the Eskimo Nebula, in the constellation Gemini, position RA 07 h 29.2 m, dec. +20◦ 55 . It is bluish, 13" in diameter, and of ninth magnitude, with a tenth-magnitude central star. The bluegreen nebula’s hazy outer regions are thought to resemble an Eskimo’s hood or clown’s ruff.

The formation resembles a person's head surrounded by a parka hood. It is surrounded by gas that composed the outer layers of a Sun-like star. The visible inner filaments are ejected by a strong wind of particles from the central star. The outer disk contains unusual light-year long filaments.

 The nebula was discovered by William Herschel on January 17, 1787, in Slough, England. He described it as "A star 9th magnitude with a pretty bright middle, nebulosity equally dispersed all around.

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Wednesday 12 June 2013

Gum Nebula discovered by C S Gum

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Gum, Colin (1924–60) - Australian radioastronomer, mapped the southern sky for radio sources and emission nebulae, and discovered the Gum Nebula in the Vela Puppis region.

Gum Nebula

Gum Nebula - A very large, near-circular emission nebula, approximately 36◦ in diameter, in the constellations Puppis and Vela. The largest known nebula in the sky, it was discovered by the Australian astronomer C S Gum (1924–60), and is believed to be an ancient supernova remnant, with an age exceeding a million years. It is a convoluted mass of nebular wisps and loops, many of them very faint, but there are also numerous brighter parts. Its distance has been estimated at 1300 light-years, indicating that the nebulosity is approximately 840 light-years across. Within one of its brightest regions both the brightest-known Otype star ζ Puppis (spectral type O5f) and the brightest Wolf–Rayet star γ 2 Velorum (type WC8), are found. The much more recent Vela pulsar and supernova remnant also lie within the Gum Nebula, which for many years has rivalled the Crab Nebula in interest for astrophysicists.

Gum Nebula
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Tuesday 11 June 2013

Crab Nebula

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The Crab Nebula is a supernova remnant and pulsar wind nebula in the constellation of Taurus. Corresponding to a bright supernova recorded by Chinese astronomers in 1054, the nebula was observed later by John Bevis in 1731.

Crab Nebula

The Crab Nebula was first identified in 1731 by John Bevis. The nebula was independently rediscovered in 1758 by Charles Messier as he was observing a bright comet

It was named by Lord Rosse for its superficial resemblance to a crab. The Crab is 6 by 4 in extent and of eighth magnitude. Its outer regions consist of twisting filaments of hydrogen expelled by the supernova, appearing red on photographs and traveling outward at over 1000 km s−1. The inner region glows with the pale yellow light of synchrotron radiation triggered by electrons emitted by the Crab Pulsar at the center, the
core of the star that exploded as a supernova. This inner region makes the Crab Nebula the best-known example of a plerion—a supernova remnant with a ‘filled’ center. The Crab emits strongly in radio waves and x-rays.
  • Distance to Earth: 6,523 light years
  • Age: 1,000 years
At the center of the nebula lies the Crab Pulsar, a neutron star 28–30 km across, which emits pulses of radiation from gamma rays to radio waves with a spin rate of 30.2 times per second. The nebula was the first astronomical object identified with a historical supernova explosion.

Crab Pulsar

At the centre of the Crab Nebula are two faint stars, one of which is the star responsible for the existence of the nebula. It was identified as such in 1942, when Rudolf Minkowski found that its optical spectrum was extremely unusual.The region around the star was found to be a strong source of radio waves in 1949and X-rays in 1963, and was identified as one of the brightest objects in the sky in gamma rays in 1967.Then, in 1968, the star was found to be emitting its radiation in rapid pulses, becoming one of the first pulsars to be discovered.

Pulsars are sources of powerful electromagnetic radiation, emitted in short and extremely regular pulses many times a second. They were a great mystery when discovered in 1967, and the team who identified the first one considered the possibility that it could be a signal from an advanced civilization.However, the discovery of a pulsating radio source in the centre of the Crab Nebula was strong evidence that pulsars were formed by supernova explosions. They now are understood to be rapidly rotating neutron stars, whose powerful magnetic field concentrates their radiation emissions into narrow beams.
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Monday 10 June 2013

Orion Nebula Discovered by Christiaan Huygens

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The Orion Nebula is a diffuse nebula situated south of Orion's Belt in the constellation of Orion. It is seen as the middle "star" in the sword of Orion, which are the three stars located south of Orion's Belt. It is one of the brightest nebulae, and is visible to the naked eye in the night sky. There are supersonic "bullets" of gas piercing the hydrogen clouds of the Orion Nebula. Each bullet is ten times the diameter of Pluto's orbit and tipped with iron atoms glowing bright blue. They were probably formed one thousand years ago from an unknown violent event.

Orion Nebula
The Orion Nebula is an example of a stellar nursery (A spiral galaxy like the Milky Way contains stars, stellar remnants , and a diffuse interstellar medium of gas and dust.) where new stars are being born. Observations of the nebula have revealed approximately 700 stars in various stages of formation within the nebula.
  • Distance to Earth: 1,344 light years
  • Age: 3 million years 
 Orion Nebula
 
The red hue is well-understood to be caused by Hα (H-alpha () is a specific red visible spectral line in the Balmer series created by hydrogen with a wavelength of 656.28 nm, which occurs when a hydrogen electron falls from its third to second lowest energy level) recombination line radiation at a wavelength of 656.3 nm. The blue-violet coloration is the reflected radiation from the massive O-class(Most stars are currently classified using the letters O, B, A, F, G, K, and M, where O stars are the hottest and the letter sequence indicates successively cooler stars up to the coolest M class) stars at the core of the nebula.

Interstellar clouds like the Orion Nebula are found throughout galaxies such as the Milky Way. They begin as gravitationally bound blobs of cold, neutral hydrogen, intermixed with traces of other elements. The cloud can contain hundreds of thousands of solar masses and extend for hundreds of light years. The tiny force of gravity that could compel the cloud to collapse is counterbalanced by the very faint pressure of the gas in the cloud.

Evolution of Orion Nebula Whether due to collisions with a spiral arm, or through the shock wave emitted from supernovae, the atoms are precipitated into heavier molecules and the result is a molecular cloud. This presages the formation of stars within the cloud, usually thought to be within a period of 10-30 million years, as regions pass the Jeans mass and the destabilized volumes collapse into disks. The disk concentrates at the core to form a star, which may be surrounded by a protoplanetary disk. This is the current stage of evolution of the nebula, with additional stars still forming from the collapsing molecular cloud. The youngest and brightest stars we now see in the Orion Nebula are thought to be less than 300,000 years old, and the brightest may be only 10,000 years in age.
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Monday 3 June 2013

Horsehead Nebula discover by Williamina Fleming

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The Horse Head Nebula (also known as Barnard 33 in bright nebula IC 434) takes its name from the horse head shape in its middle. The first human to discover it was Williamina Fleming in 1888 at Harvard University. It is one of the most identifiable nebulae because of the shape of its swirling cloud of dark dust and gases, which bears some semblance to a horse's head when viewed from Earth.

Horsehead Nebula

The Horsehead Nebula is a dark nebula in the constellation Orion. The nebula is located just to the south of the star Alnitak, which is farthest east on Orion's Belt, and is part of the much larger Orion Molecular Cloud Complex.

  • Constellation: Orion
  • Distance to Earth:1,500 light-years

Horsehead Nebula

The red glow originates from hydrogen gas predominantly (Mainly) behind the nebula, ionized by the nearby bright star Sigma Orionis. The darkness of the Horsehead is caused mostly by thick dust, although the lower part of the Horsehead's neck casts a shadow to the left. Streams of gas leaving the nebula are funneled by a strong magnetic field. Bright spots in the Horsehead Nebula's base are young stars just in the process of forming.

Horsehead nebula

 The nebula is a favorite target for amateur and professional astronomers. It is shadowy in optical light. It appears transparent and ethereal when seen at infrared wavelengths. The rich tapestry of the Horsehead Nebula pops out against the backdrop of Milky Way stars and distant galaxies that easily are visible in infrared light.

                                                                             The nebula is part of the Orion Molecular Cloud, located about 1,500 light-years away in the constellation Orion. The cloud also contains other well-known objects such as the Great Orion Nebula (M42), the Flame Nebula, and Barnard's Loop. It is one of the nearest and most easily photographed regions in which massive stars are being formed.

Horsehead Nebula
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