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...)

General images - load new batch

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

Image 1A voting session is conducted in 2006 International Astronomical Union's general assembly for determining a new definition of a planet (from Astronomer)
Image 2Calendrical functions of the Berlin Gold Hat c. 1000 BC (from History of astronomy)
Image 3Artist 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 4Comparison of CMB (Cosmic microwave background) results from satellites COBE, WMAP and Planck documenting a progress in 1989–2013 (from History of astronomy)
Image 59th-century diagram of the positions of the seven planets on 18 March 816, from the Leiden Aratea (from History of astronomy)
Image 6Sunset at the equinox from the prehistoric site of Pizzo Vento at Fondachelli Fantina, Sicily (from History of astronomy)
Image 7The Antikythera Mechanism was an analog computer from 150 to 100 BC designed to calculate the positions of astronomical objects. (from History of astronomy)
Image 8Portrait 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 9One 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 10ALMA is the world's most powerful telescope for studying the Universe at submillimeter and millimeter wavelengths. (from Observational astronomy)
Image 11Arabic astrolabe from 1079 to 1080 AD (from History of astronomy)
Image 12The Oort cloud, one of the most successful theoretical models about the Solar System (from Theoretical astronomy)
Image 13Historical accuracy of atomic clocks from NIST. (from Theoretical astronomy)
Image 14Historical Jantar Mantar observatory in Jaipur, India (from History of astronomy)
Image 15Amateur astronomy groups are often involved in outreach to introduce astronomy to the general public (from Amateur astronomy)
Image 16The Crab Nebula as seen in various wavelengths (from Observational astronomy)
Image 17An 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 18An assembly in Estonia to observe meteors (from Observational astronomy)
Image 19Amateur astronomer recording observations of the sun. (from Amateur astronomy)
Image 20The inflationary theory as an augmentation to the Big Bang theory was first proposed by Alan Guth of MIT. Inflation solves the 'horizon problem' by making the early universe much more compact than was assumed in the standard model. Given such smaller size, causal contact (i.e., thermal communication) would have been possible among all regions of the early universe. The image was an adaptation from various generic charts depicting the growth of the size of the observable universe, for both the standard model and inflationary model respectively, of the Big Bang theory. (from Physical cosmology)
$Image 2150 cm refracting telescope at Nice Observatory (from Observational astronomy)$

Image 2150 cm refracting telescope at Nice Observatory (from Observational astronomy)
Image 22Sir Patrick Moore was one of the world's leading popularisers of astronomy. (from Amateur astronomy)
Image 23The main platform at La Silla hosts a huge range of telescopes with which astronomers can explore the Universe. (from Observational astronomy)
Image 24An example of a gravitational lens found in the DESI Legacy Surveys data. There are four sets of lensed images in DESI-090.9854-35.9683, corresponding to four distinct background galaxies—from the outermost giant red arc to the innermost bright blue arc, arranged in four concentric circles. All of them are gravitationally warped—or lensed—by the orange galaxy at the very center. Dark matter is expected to produce gravitational lensing also. (from Physical cosmology)
Image 25Babylonian tablet in the British Museum recording Halley's Comet in 164 BC (from History of astronomy)
Image 26History 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 27"El Caracol" observatory temple at Chichen Itza, Mexico (from History of astronomy)
Image 28The 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 29Mayall telescope at Kitt Peak National Observatory (from Observational astronomy)
Image 30Segment of the astronomical ceiling of Senenmut's Tomb (circa 1479–1458 BC), 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 31The Hubble Space Telescope (from History of astronomy)
Image 32Ultra HD photography taken at La Silla Observatory (from Observational astronomy)
Image 33The Nebra sky disk, Germany, 1800–1600 BC (from History of astronomy)
Image 34An amateur astrophotography setup with an automated guide system connected to a laptop (from Observational astronomy)
Image 35Places like Paranal Observatory offer crystal clear skies for observing astronomical objects with or without instruments. (from Amateur astronomy)
Image 36Map 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 37Overview of types of observational astronomy by observed wavelengths and their observability. (from Observational astronomy)
Image 38Southern Hemisphere (from History of astronomy)

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Featured article - show another

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

The location of Barnard's Star, c. 2006 (south is up)

Barnard's Star is a small red dwarf star in the constellation of Ophiuchus. At a distance of 5.96 light-years (1.83 pc) from Earth, it is the fourth-nearest-known individual star to the Sun after the three components of the Alpha Centauri system, and is the closest star in the northern celestial hemisphere. Its stellar mass is about 16% of the Sun's, and it has 19% of the Sun's diameter. Despite its proximity, the star has a dim apparent visual magnitude of +9.5 and is invisible to the unaided eye; it is much brighter in the infrared than in visible light.

The star is named after Edward Emerson Barnard, an American astronomer who in 1916 measured its proper motion as 10.3 arcseconds per year relative to the Sun, the highest known for any star. The star had previously appeared on Harvard University photographic plates in 1888 and 1890. (Full article...)

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Did you know - show different entries

... that the Lyman-alpha blob 1 is a blob of gas 300,000 light-years across located some 11.5 billion light-years from Earth?
... that 51 Ophiuchi has a disk of dust and gas that is likely a planetary system in the late stages of formation?
... that the Magellan Planet Search Program has discovered five eccentric Jupiter-mass extra-solar planets since the program started gathering data in December 2002?
... that asteroids with two moons, like 1994 CC, comprise only 1% of the near-Earth objects?
... that pictures by amateur astrophotographer Steve Mandel help to explore faint nebulae of the Milky Way?

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... 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?
... that in early depictions of Uranus in fiction, the planet was portrayed as solid
... that fictional planets of the Solar System include planets between Venus and Earth, planets on the inside of a hollow Earth, and a planet "behind the Earth"?
... that Kim Ye-ji's performance in the 10 meter air pistol at the 2024 Summer Olympics led her to be dubbed the "coolest person on the planet"?
... that the star TRAPPIST-1 has seven planets, several of which may have temperatures that would allow the existence of liquid water (artist's impression depicted)?
... that Michael Collins has been called "one of the best clarinettists walking the planet" by The Times?

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WikiProjects

WikiProject Astronomy	WikiProject Solar System



WikiProject Cosmology	WikiProject Spaceflight

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Credit: NASA / ESA / G. Illingworth, D. Magee, and P. Oesch, University of California, Santa Cruz / R. Bouwens, Leiden University / the HUDF09 Team

The Hubble eXtreme Deep Field (HXDF), released on September 25, 2012, is an image of a portion of space in the center of the Hubble Ultra-Deep Field image. It covers an area of 2.3 arcminutes by 2 arcminutes, or approximately 80% of the area of the HUDF. The HXDF contains approximately 5,500 galaxies, the oldest of which are seen as they were 13.2 billion years ago.

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Astronomy News

21 November 2024 –: The European Southern Observatory announces that its astronomers in Chile capture the first close-up image of a star outside the Milky Way. (The New York Times)
20 November 2024 – Discoveries of exoplanets: In a study published by the Nature journal, astronomers announce the discovery of IRAS 04125+2902 b, a newborn exoplanet. The discovery was made by Madyson Barber, a graduate student at the University of North Carolina at Chapel Hill. (Nature) (ABC News)

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January anniversaries

1 January 1925 – Astronomer Edwin Hubble formally presents his discovery of galaxies outside the Milky Way at a meeting of the American Astronomical Society
1 January 1952 – The Kyiv Planetarium opens in Kyiv, Ukraine
3 January 1888 – The 91-centimeter refracting telescope at Lick Observatory, the world's largest telescope from 1888 to 1897, sees its first light
3 January 1999 – The Mars Polar Lander is launched by NASA to study the soil and climate of Planum Australe, a region near the south pole on Mars
4 January 2004 – The Mars rover Spirit lands, three weeks ahead of twin rover Opportunity, and begins exploring the Red Planet
14 January 2005 – The probe Huygens lands on Titan, a moon of Saturn, in the first successful landing in the outer Solar System
26 January 1949 – Hale Telescope, which introduced several innovations to telescope construction and was the world's largest telescope for nearly 30 years, has its first light

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Space-related Portals

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Astronomical events

All times UT unless otherwise specified.

3 January, 15:24	Quadrantids peak
4 January, 07:59	Earth at perihelion
4 January, 17:24	Moon occults Saturn
5 January, 15:17	Moon occults Neptune
7 January, 23:35	Moon at perigee
10 January, 03:59	Venus at greatest eastern elongation
13 January	Comet ATLAS at maximum brightness
13 January, 22:27	Full moon
14 January, 03:43	Moon occults Mars
16 January, 01:17	Mars at opposition
21 January, 04:55	Moon at apogee
29 January, 12:36	New moon