Portal:Astronomy

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The Astronomy Portal

Introduction

Astronomy is a natural science that studies celestial objects and the phenomena that occur in the cosmos. It uses mathematics, physics, and chemistry in order to explain their origin and their overall evolution. Objects of interest include planets, moons, stars, nebulae, galaxies, meteoroids, asteroids, 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 Egyptians, Babylonians, Greeks, Indians, 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.

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...)

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

Image 1The Oort cloud, one of the most successful theoretical model about the Solar System (from Theoretical astronomy)
Image 2Sunset at the equinox from the prehistoric site of Pizzo Vento at Fondachelli Fantina, Sicily (from History of astronomy)
Image 3ALMA is the world's most powerful telescope for studying the Universe at submillimeter and millimeter wavelengths. (from Observational astronomy)
Image 4The Nebra sky disk, Germany, 1800 - 1600 BC (from History of astronomy)
Image 5History of the Universe – gravitational waves are hypothesized to arise from cosmic inflation, a rapidly accelerated expansion just after the Big Bang (from Physical cosmology)
Image 6The Hubble Space Telescope (from History of astronomy)
Image 7Calendrical functions of the Berlin Gold Hat c. 1000 BC (from History of astronomy)
Image 8An amateur astrophotography setup with an automated guide system connected to a laptop (from Observational astronomy)
Image 9Sir Patrick Moore was one of the world's leading popularisers of astronomy. (from Amateur astronomy)
Image 10Babylonian tablet in the British Museum recording Halley's comet in 164 BC (from History of astronomy)
Image 11An assembly in Estonia to observe meteors (from Observational astronomy)
Image 12Segment of the astronomical ceiling of Senenmut's Tomb (circa 1479–1458 BCE), depicting constellations, protective deities, and twenty-four segmented wheels for the hours of the day and the months of the year (from History of astronomy)
Image 13Map of the Milky Way Galaxy, with the constellations that cross the galactic plane in each direction and the known prominent components annotated including main arms, spurs, bar, nucleus/bulge, notable nebulae and globular clusters (from History of astronomy)
Image 14Mayall telescope at Kitt Peak National Observatory (from Observational astronomy)
Image 15Amateur astronomy groups are often involved in outreach in order to introduce astronomy to the general public (from Amateur astronomy)
Image 16An 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 17Historical accuracy of atomic clocks from NIST. (from Theoretical astronomy)
Image 18The main platform at La Silla hosts a huge range of telescopes with which astronomers can explore the Universe. (from Observational astronomy)
Image 199th-century diagram of the positions of the seven planets on 18 March 816, from the Leiden Aratea (from History of astronomy)
$Image 2050 cm refracting telescope at Nice Observatory (from Observational astronomy)$

Image 2050 cm refracting telescope at Nice Observatory (from Observational astronomy)
Image 21Portrait 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 22Artist conception of the Big Bang cosmological model, the most widely accepted out of all in physical cosmology (neither time nor size to scale) (from Physical cosmology)
Image 23The Northern Hemisphere page from Johann Bayer's 1661 edition of Uranometria - the first atlas to have star charts covering the entire celestial sphere (from History of astronomy)
Image 24Historical Jantar Mantar observatory in Jaipur, India (from History of astronomy)
Image 25Places like Paranal Observatory offer crystal clear skies for observing astronomical objects with or without instruments. (from Amateur astronomy)
Image 26Ultra HD photography taken at La Silla Observatory (from Observational astronomy)
Image 27A voting session is conducted in 2006 International Astronomical Union's general assembly for determining a new definition of a planet (from Astronomer)
Image 28Amateur astronomer recording observations of the sun. (from Amateur astronomy)
Image 29Southern Hemisphere (from History of astronomy)
Image 30Comparison of CMB (Cosmic microwave background) results from satellites COBE, WMAP and Planck documenting a progress in 1989–2013 (from History of astronomy)
Image 31"El Caracol" observatory temple at Chichen Itza, Mexico (from History of astronomy)
Image 32The Antikythera Mechanism was an analog computer from 150 to 100 BC designed to calculate the positions of astronomical objects. (from History of astronomy)
Image 33Arabic astrolabe from 1079 to 1080 AD (from History of astronomy)
Image 34The Crab Nebula as seen in various wavelengths (from Observational astronomy)
Image 35One 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 36Overview of types of observational astronomy by observed wavelengths and their observability. (from Observational astronomy)

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

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Venus is the second planet from the Sun. It is a terrestrial planet and is the closest in mass and size to its orbital neighbour Earth. Venus is notable for having the densest atmosphere of the terrestrial planets, composed mostly of carbon dioxide with a thick, global sulfuric acid cloud cover. At the surface it has a mean temperature of 737 K (464 °C; 867 °F) and a pressure of 92 times that of Earth's at sea level. These extreme conditions compress carbon dioxide into a supercritical state close to Venus's surface.

Internally, Venus has a core, mantle, and crust. Venus lacks an internal dynamo, and its weakly induced magnetosphere is caused by atmospheric interactions with the solar wind. Internal heat escapes through active volcanism, resulting in resurfacing instead of plate tectonics. Venus is one of two planets in the Solar System, the other being Mercury, that have no moons. Conditions perhaps favourable for life on Venus have been identified at its cloud layers. Venus may have had liquid surface water early in its history with a habitable environment, before a runaway greenhouse effect evaporated any water and turned Venus into its present state. (Full article...)

List of featured articles

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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?

More Did you know (auto generated)

... that the Springfield Science Museum is home to the oldest operating projection planetarium in the United States?
... that Michael Collins has been called "one of the best clarinettists walking the planet" by The Times?
... that examples of artificial planets in science fiction include Riverworld, the Well World, and the Death Star?
... that the active galaxy 3C 120 was given the variable-star designation BW Tauri because of its variability in the visible spectrum?
... that in many works of fiction, the asteroid belt is the remnants of a destroyed planet?
... that fictional depictions of Jupiter have portrayed human habitation on the planet and its moons both by altering the environment to suit humans and altering humans to be suited to the environment?

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WikiProjects

WikiProject Astronomy	WikiProject Solar System



WikiProject Cosmology	WikiProject Spaceflight

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T Tauri is a variable star in the constellation Taurus, the prototype of the T Tauri stars. It was discovered in October 1852 by John Russell Hind.

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Astronomy News

20 February 2024 –: Astronomers identify the most luminous object ever observed, QSO J0529-4351, a quasar that accretes around one solar mass per day. (The Guardian) (Nature.com)

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June anniversaries

2 June 1966 – Surveyor 1 lands on the moon, first US spacecraft to do so
3 June 1966 – Gemini 9 (Gemini Titan 9A) launch from Cape Canaveral, Florida
19 June 1976 – The Viking 1 orbiter arrives in Mars orbit
24 June 2004 – First private spaceflight, SpaceShipOne piloted by Mike Melvill
27 June 1996 – Galileo probe, flyby of Ganymede (Jupiter's largest moon)
30 June 2001 – The NASA Explorer mission, MAP (Microwave Anisotropy Probe), is launched to measure the temperature of cosmic background radiation (remnant heat from the Big Bang)

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Space-related Portals

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Astronomical events

All times UT unless otherwise specified.

1 June, 02:54	Moon occults Neptune
2 June, 07:23	Moon at perigee
4 June, 15:12	Venus at superior conjunction; occultation
6 June, 12:38	New moon
14 June, 13:36	Moon at apogee
14 June, 16:15	Mercury at superior conjunction
20 June, 20:51	Earth northern solstice
22 June, 01:08	Full moon
27 June, 11:45	Moon at perigee
27 June, 15:00	Moon occults Saturn
28 June, 08:58	Moon occults Neptune