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 1Places like Paranal Observatory offer crystal clear skies for observing astronomical objects with or without instruments. (from Amateur astronomy)
Image 2Sir Patrick Moore was one of the world's leading popularisers of astronomy. (from Amateur astronomy)
Image 3An 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 4One 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 5ALMA is the world's most powerful telescope for studying the Universe at submillimeter and millimeter wavelengths. (from Observational astronomy)
$Image 650 cm refracting telescope at Nice Observatory (from Observational astronomy)$

Image 650 cm refracting telescope at Nice Observatory (from Observational astronomy)
Image 7Historical accuracy of atomic clocks from NIST. (from Theoretical astronomy)
Image 8Mayall telescope at Kitt Peak National Observatory (from Observational astronomy)
Image 9Map 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 10Ultra HD photography taken at La Silla Observatory (from Observational astronomy)
Image 11Sunset at the equinox from the prehistoric site of Pizzo Vento at Fondachelli Fantina, Sicily (from History of astronomy)
Image 12Comparison of CMB (Cosmic microwave background) results from satellites COBE, WMAP and Planck documenting a progress in 1989–2013 (from History of astronomy)
Image 13The 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 14Calendrical functions of the Berlin Gold Hat c. 1000 BC (from History of astronomy)
Image 15Historical Jantar Mantar observatory in Jaipur, India (from History of astronomy)
Image 16Amateur astronomer recording observations of the sun. (from Amateur astronomy)
Image 17Amateur astronomy groups are often involved in outreach in order to introduce astronomy to the general public (from Amateur astronomy)
Image 18Southern Hemisphere (from History of astronomy)
Image 19An assembly in Estonia to observe meteors (from Observational astronomy)
Image 20A voting session is conducted in 2006 International Astronomical Union's general assembly for determining a new definition of a planet (from Astronomer)
Image 21The main platform at La Silla hosts a huge range of telescopes with which astronomers can explore the Universe. (from Observational astronomy)
Image 229th-century diagram of the positions of the seven planets on 18 March 816, from the Leiden Aratea (from History of astronomy)
Image 23Arabic astrolabe from 1079 to 1080 AD (from History of astronomy)
Image 24Segment 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 25Artist 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 26Portrait 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 27An amateur astrophotography setup with an automated guide system connected to a laptop (from Observational astronomy)
Image 28The Oort cloud, one of the most successful theoretical model about the Solar System (from Theoretical astronomy)
Image 29The Nebra sky disk, Germany, 1800 - 1600 BC (from History of astronomy)
Image 30The Hubble Space Telescope (from History of astronomy)
Image 31Babylonian tablet in the British Museum recording Halley's comet in 164 BC (from History of astronomy)
Image 32Overview of types of observational astronomy by observed wavelengths and their observability. (from Observational astronomy)
Image 33"El Caracol" observatory temple at Chichen Itza, Mexico (from History of astronomy)
Image 34The Crab Nebula as seen in various wavelengths (from Observational astronomy)
Image 35The Antikythera Mechanism was an analog computer from 150 to 100 BC designed to calculate the positions of astronomical objects. (from History of astronomy)
Image 36History of the Universe – gravitational waves are hypothesized to arise from cosmic inflation, a rapidly accelerated expansion just after the Big Bang (from Physical cosmology)

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Featured article - show another

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

The definition of the term planet has changed several times since the word was coined by the ancient Greeks. Greek astronomers employed the term ἀστέρες πλανῆται (asteres planetai), 'wandering stars', for star-like objects which apparently moved over the sky. Over the millennia, the term has included a variety of different celestial bodies, 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 dynamically dominates its region (that is, whether it controls the fate of other smaller bodies in its vicinity) or whether it is in hydrostatic equilibrium (in practice, this is always taken rather loosely to mean whether it has become gravitationally rounded and compacted). These may be characterized as the dynamical dominance definition and the geophysical definition. (Full article...)

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Did you know - show different entries

... that Caroline Moore was 14 years old when she discovered supernova 2008ha?
... that although Charles Messier discovered the galaxy M91 in 1781, it was added to his catalogue only two centuries later?
... that the fall of the Neuschwanstein meteorite in 2002 was observed by the European Fireball Network and outdoor witnesses through most of Central Europe?
... that AG Pegasi has been described as the slowest nova ever recorded?

More Did you know facts

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... that Nandivada Rathnasree, who ran Delhi's planetarium, proposed that astronomers could be taught using India's stone-built observatories?
... that examples of artificial planets in science fiction include Riverworld, the Well World, and the Death Star?
... 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 King Gizzard & the Lizard Wizard's "cli-fi" thrash metal album addresses a mix of current ecological threats and attempts to find another planet to live on?
... that it took five years of observations to find the planet orbiting the star HD 175167?
... 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

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)
24 November 2023 –: Astronomers at the Telescope Array Project in Utah, United States, observe the second largest cosmic ray ever detected, the so-called Amaterasu particle, with an energy of 244 EeV. (Cosmos Magazine)

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April anniversaries

2 April 1968 – The epic science fiction film, 2001: A Space Odyssey is released
3 April 2014 – NASA announces that the Cassini orbiter has found evidence of an underground body of water on Enceladus, a moon of Saturn
7 April 2001 – Mars Odyssey orbiter is launched to map and search for water on Mars
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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Space-related Portals

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Astronomical events

All times UT unless otherwise specified.

6 April, 09:25	Moon occults Saturn
7 April, 08:11	Moon occults Neptune
7 April, 16:47	Moon occults Venus
7 April, 17:53	Moon at perigee
8 April, 18:18	New moon and Total Solar Eclipse
11 April, 22:53	Mercury at inferior conjunction
20 April, 02:09	Moon at apogee
22 April, 06:44	Lyrids peak
23 April, 23:49	Full moon