Portal:Astronomy

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Astronomy portal

Astronomy is a natural science that is the study of celestial objects (such as moons, planets, stars, nebulae, and galaxies), the physics, chemistry, and evolution of such objects, and phenomena that originate outside the atmosphere of Earth, including supernovae explosions, gamma ray bursts, and cosmic background radiation.

Astronomy is one of the oldest sciences. Prehistoric cultures have left astronomical artifacts such as the Egyptian monuments and Nubian monuments, and early civilizations such as the Babylonians, Greeks, Chinese, Indians, Iranians and Maya performed methodical observations of the night sky. However, the invention of the telescope was required before astronomy was able to develop into a modern science. Historically, astronomy has included disciplines as diverse as astrometry, celestial navigation, observational astronomy, and the making of calendars, but professional astronomy is nowadays often considered to be synonymous with astrophysics.

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GRB 970508 was a gamma-ray burst (GRB) detected on May 8, 1997, at 21:42 UTC. A gamma-ray burst is a highly luminous flash associated with an explosion in a distant galaxy and producing gamma rays, the most energetic form of electromagnetic radiation, and often followed by a longer-lived "afterglow" emitted at longer wavelengths (X-ray, ultraviolet, optical, infrared, and radio).

GRB 970508 was detected by the Gamma Ray Burst Monitor on the Italian–Dutch X-ray astronomy satellite BeppoSAX. Astronomer Mark Metzger determined that GRB 970508 occurred at least 6 billion light years from Earth; this was the first measurement of the distance to a gamma-ray burst.

Until this burst, astronomers had not reached a consensus regarding how far away GRBs occur from Earth. Some supported the idea that GRBs occur within the Milky Way, but are visibly faint because they are not highly energetic. Others concluded that GRBs occur in other galaxies at cosmological distances and are extremely energetic. Although the possibility of multiple types of GRBs meant that the two theories were not mutually exclusive, the distance measurement unequivocally placed the source of the GRB outside the Milky Way, effectively ending the debate.

GRB 970508 was also the first burst with an observed radio frequency afterglow. By analyzing the fluctuating strength of the radio signals, astronomer Dale Frail calculated that the source of the radio waves had expanded almost at the speed of light. This provided strong evidence that GRBs are relativistically expanding explosions.

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Did you know

... that Jerry Nelson is the principal designer and project scientist for the Keck telescopes?
... that five supernovae have been found in the Messier 100 spiral galaxy?
... that the Antlia Dwarf galaxy may have distorted the shape of its neighbour NGC 3109 one billion years ago?
... that AP Columbae, the closest young star known, formed after the dinosaurs became extinct?
... that a planet was discovered around the star MOA-2009-BLG-387L after it eclipsed a background star, refracting the star's light in a process called gravitational microlensing?

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Projects

WikiProject Astronomy	WikiProject Solar System



WikiProject Cosmology	WikiProject Spaceflight

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Space-related Portals

Star	Spaceflight	Moon


Space	Solar System	Mars

X-ray astronomy	Cosmology	Jupiter

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Credit: NASA / JPL-Caltech / Space Science Institute

Mimas is a moon of Saturn. It was discovered in 1789 by William Herschel, for whom the large crater in the image is named after. It is the twentieth-largest moon in the Solar System, and the smallest astronomical body that is known to be rounded in shape because of self-gravitation. This photograph of Mimas was taken by the unmanned spacecraft Cassini in 2010.

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April anniversaries

3 April 2014 – NASA announces that the Cassini orbiter has found evidence of an underground body of water on Enceladus, a moon of Saturn
12 April 1961 – Cosmonaut Yuri Gagarin becomes the first human to enter outer space when he is launched into orbital flight in Vostok 1
19 April 1971 – The first space station, Salyut 1, is launched into orbit
24 April 1990 – The Hubble Space Telescope, a powerful research tool and public relations boon for astronomy, is launched into orbit

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Things you can do

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Requests: Borde-Vilenkin-Guth Theorem, Antigalaxy, Sunspot index, undefined names in the List of astronomers, More...
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Astronomy featured article candidates:

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Astronomy articles for which peer review has been requested:

Epsilon Eridani (entry)
Jupiter Trojan (entry)

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Wikibooks

These books may be in various stages of development. See also the related Science and Mathematics bookshelves.

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Solar System

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Astronomical events

All times UT unless otherwise specified.

6 April, 08:31	Moon occults Venus
7 April, 11:24	New moon
7 April, 17:29	Moon at perigee
9 April	Uranus at conjunction
18 April, 14:00	Mercury at greatest eastern elongation
21 April, 15:49	Moon at apogee
22 April, 05:24	Full moon
22 April, 08:00	Lyrids peak