Portal:Astronomy

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The Astronomy Portal

Introduction

Astronomy (from Greek: ἀστρονομία, literally meaning the science that studies the laws of the stars) is a natural science that studies celestial objects and phenomena. It uses mathematics, physics, and chemistry in order to explain their origin and evolution. Objects of interest include planets, moons, stars, nebulae, galaxies, and comets. Relevant phenomena include supernova explosions, gamma ray bursts, quasars, blazars, pulsars, and cosmic microwave background radiation. More generally, astronomy studies everything that originates beyond Earth's atmosphere. Cosmology is a branch of astronomy that studies the universe as a whole.

Astronomy is one of the oldest natural sciences. The early civilizations in recorded history made methodical observations of the night sky. These include the Babylonians, Greeks, Indians, Egyptians, Chinese, Maya, and many ancient indigenous peoples of the Americas. In the past, astronomy included disciplines as diverse as astrometry, celestial navigation, observational astronomy, and the making of calendars. Nowadays, professional astronomy is often said to be the same as astrophysics.

Professional astronomy is split into observational and theoretical branches. Observational astronomy is focused on acquiring data from observations of astronomical objects. This data is then analyzed using basic principles of physics. Theoretical astronomy is oriented toward the development of computer or analytical models to describe astronomical objects and phenomena. These two fields complement each other. Theoretical astronomy seeks to explain observational results and observations are used to confirm theoretical results.

Astronomy is one of the few sciences in which amateurs play an active role. This is especially true for the discovery and observation of transient events. Amateur astronomers have helped with many important discoveries, such as finding new comets. (Full article...)

General images - load new batch

The following are images from various astronomy-related articles on Wikipedia.

Image 150 cm refracting telescope at Nice Observatory. (from Observational astronomy)
Image 2Telescope set up in Brooklyn Bridge Park for a public stargazing session (from Amateur astronomy)
Image 3Comparison of CMB (Cosmic microwave background) results from satellites COBE, WMAP and Planck documenting a progress in 1989–2013. (from History of astronomy)
Image 4Mayall telescope at Kitt Peak National Observatory (from Observational astronomy)
Image 5Chart from Senemut's tomb, 18th dynasty (from History of astronomy)
Image 6Sir Patrick Moore was one of the world's leading popularisers of astronomy. (from Amateur astronomy)
Image 7"El Caracol" observatory temple at Chichen Itza, Mexico. (from History of astronomy)
Image 8The Astronomer, 1668, by Johannes Vermeer (from Astronomer)
Image 9An amateur astrophotography setup with an automated guide system connected to a laptop. (from Observational astronomy)
Image 10Sunset at the equinox from the prehistoric site of Pizzo Vento at Fondachelli Fantina, Sicily (from History of astronomy)
Image 11Places like Paranal Observatory offer crystal clear skies for observing astronomical objects with or without instruments. (from Amateur astronomy)
Image 12Historical Jantar Mantar observatory in Jaipur, India. (from History of astronomy)
Image 13One of the Oldest Observatories in South America is the Quito Astronomical Observatory, founded in 1873 and located 12 minutes south of the Equator in Quito, Ecuador. The Quito Astronomical Observatory is the National Observatory of Ecuador and is located in the Historic Center of Quito and is managed by the National Polytechnic School. (from Observational astronomy)
Image 14An assembly in Estonia to observe meteors (from Observational astronomy)
Image 15Calendrical functions of the Berlin Gold Hat c. 1000 BC (from History of astronomy)
Image 16The Nebra sky disk Germany 1600 BC (from History of astronomy)
Image 17Ultra HD photography taken at La Silla Observatory. (from Observational astronomy)
Image 18The Antikythera Mechanism was an analog computer from 150–100 BC designed to calculate the positions of astronomical objects. (from History of astronomy)
Image 19History of the Universe – gravitational waves are hypothesized to arise from cosmic inflation, a faster-than-light expansion just after the Big Bang (from Physical cosmology)
Image 20The main platform at La Silla hosts a huge range of telescopes with which astronomers can explore the Universe. (from Observational astronomy)
Image 219th-century diagram of the positions of the seven planets on 18 March 816, from the Leiden Aratea. (from History of astronomy)
Image 22Portrait of the Flemish astronomer Ferdinand Verbiest who became Head of the Mathematical Board and Director of the Observatory of the Chinese emperor in 1669 (from Astronomer)
Image 23An image of the Cat's Paw Nebula created combining the work of professional and amateur astronomers. The image is the combination of the 2.2-metre MPG/ESO telescope of the La Silla Observatory in Chile and a 0.4-meter amateur telescope. (from Amateur astronomy)
Image 24Historical accuracy of atomic clocks from NIST. (from Theoretical astronomy)
Image 25ALMA is the world's most powerful telescope for studying the Universe at submillimeter and millimeter wavelengths. (from Observational astronomy)
Image 26Babylonian tablet in the British Museum recording Halley's comet in 164 BC. (from History of astronomy)
Image 27Arabic astrolabe from 1208 AD (from History of astronomy)
Image 28Hubble Space Telescope. (from History of astronomy)

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This is a Featured article, which represents some of the best content on English Wikipedia..

Photograph of the crescent of the planet Neptune (top) and its moon Triton (center), taken by Voyager 2 during its 1989 flyby

The definition of planet, since the word was coined by the ancient Greeks, has included within its scope a wide range of celestial bodies. Greek astronomers employed the term asteres planetai (ἀστέρες πλανῆται), "wandering stars", for star-like objects which apparently moved over the sky. Over the millennia, the term has included a variety of different objects, from the Sun and the Moon to satellites and asteroids.

In modern astronomy, there are two primary conceptions of a 'planet'. Disregarding the often inconsistent technical details, they are whether an astronomical body moves like a planet (that is, whether its orbit and relationship to other bodies are similar to those of the classical planets) or whether it looks like a planet (that is, whether it is round or has planetary geology). These may be characterized as the orbital definition and the geophysical definition. (Full article...)

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Did you know - show different entries

... that the Lone Signal project sends messages by ordinary citizens to extraterrestrial civilizations using the Jamesburg Earth Station?
... that 6Q0B44E, a recently discovered satellite of Earth, is thought to be a large piece of space debris?
... that approximately one-third of nearby galaxies contain low-ionization nuclear emission-line regions?
... that lunar lava tubes could provide natural shelters for manned lunar habitats?
... that many geographic features on Campbell Island, New Zealand, were named for members of the French 1874 Transit of Venus astronomical expedition?

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WikiProjects

WikiProject Astronomy	WikiProject Solar System



WikiProject Cosmology	WikiProject Spaceflight

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Credit: NASA / ESA / Hubble Heritage Team (STScI/AURA)

Messier 82, also known as NGC 3034, Cigar Galaxy, and M82, is the prototype starburst galaxy about 12 million light-years away in the constellation Ursa Major. The starburst galaxy is five times more luminous than the whole Milky Way, and one hundred times more luminous than our galaxy's center. This mosaic image, taken by the Hubble Telescope, is the sharpest wide-angle view ever obtained of Messier 82.

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Astronomy News

26 May 2021 – May 2021 lunar eclipse: A total lunar eclipse occurs, the second-shortest of the 21st century, with totality lasting for only 14 minutes. Nicknamed the Super Flower Blood Moon, the eclipse was visible over the Pacific Ocean and Oceania, with South and East Asia seeing the eclipse at moonrise, and the Americas seeing the eclipse at moonset. (Space.com)
17 February 2021 – Discoveries of exoplanets: Astronomers announce the discovery of HD 110082 b, a sub-Neptune exoplanet that is three times larger than Earth and which orbits a relatively young star. (Phys.org)

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July anniversaries

1 July 2004 – The Cassini spacecraft arrives at Saturn after entering orbit
4 July 1997 – Mars Pathfinder and its rover, Sojourner, land on Mars, with the latter becoming the first rover to successfully travel the planet
5 July 1687 – Sir Isaac Newton's Philosophiæ Naturalis Principia Mathematica, which formulated the laws of motion and universal gravitation and applied them to celestial bodes, is first published
13 July 2007 – Gran Telescopio Canarias undergoes first light, becoming the largest telescope in the world
20 July 1969 – As part of the Apollo 11 mission, Americans Neil Armstrong and Buzz Aldrin become the first men to walk on the Moon
20 July 1976 – Viking 1 becomes the first spacecraft to successfully land on Mars and perform its mission
26 July 1971 – Apollo 15 launches with lunar rover payload

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Space-related Portals

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Astronomical events

All times UT unless otherwise specified.

3 July, 11:41	Close approach of Venus and M44
4 July, 19:59	Mercury at greatest western elongation of 21.6 degrees from the Sun
5 July, 14:48	Moon at apogee
6 July, 02:59	Earth at aphelion
7 July, 04:39	Conjunction of the Moon and Mercury
10 July, 01:17	New moon
21 July, 10:24	Moon at perigee
24 July, 02:37	Full moon
28 July, 03:17	Peak of Delta Aquariids meteor shower