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 1Portrait 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 2Sir Patrick Moore was one of the world's leading popularisers of astronomy. (from Amateur astronomy)
Image 3Ultra HD photography taken at La Silla Observatory (from Observational astronomy)
Image 4The Hubble Space Telescope (from History of astronomy)
Image 5Babylonian tablet in the British Museum recording Halley's comet in 164 BC (from History of astronomy)
Image 6Comparison of CMB (Cosmic microwave background) results from satellites COBE, WMAP and Planck documenting a progress in 1989–2013 (from History of astronomy)
Image 7The Nebra sky disk, Germany, 1800 - 1600 BC (from History of astronomy)
Image 8An assembly in Estonia to observe meteors (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 10Places like Paranal Observatory offer crystal clear skies for observing astronomical objects with or without instruments. (from Amateur astronomy)
Image 11Calendrical functions of the Berlin Gold Hat c. 1000 BC (from History of astronomy)
Image 12Overview of types of observational astronomy by observed wavelengths and their observability. (from Observational astronomy)
Image 13Mayall telescope at Kitt Peak National Observatory (from Observational astronomy)
Image 14History 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 159th-century diagram of the positions of the seven planets on 18 March 816, from the Leiden Aratea (from History of astronomy)
Image 16The main platform at La Silla hosts a huge range of telescopes with which astronomers can explore the Universe. (from Observational astronomy)
Image 17One 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 18An amateur astrophotography setup with an automated guide system connected to a laptop (from Observational astronomy)
Image 19Artist 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 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 Crab Nebula as seen in various wavelengths (from Observational astronomy)
Image 22Amateur astronomer recording observations of the sun. (from Amateur astronomy)
Image 23ALMA is the world's most powerful telescope for studying the Universe at submillimeter and millimeter wavelengths. (from Observational astronomy)
Image 24Arabic astrolabe from 1079 to 1080 AD (from History of astronomy)
Image 25Historical accuracy of atomic clocks from NIST. (from Theoretical astronomy)
$Image 2650 cm refracting telescope at Nice Observatory (from Observational astronomy)$

Image 2650 cm refracting telescope at Nice Observatory (from Observational astronomy)
Image 27The Oort cloud, one of the most successful theoretical model about the Solar System (from Theoretical astronomy)
Image 28Amateur astronomy groups are often involved in outreach in order to introduce astronomy to the general public (from Amateur astronomy)
Image 29"El Caracol" observatory temple at Chichen Itza, Mexico (from History of astronomy)
Image 30The 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 31Segment 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 32Southern Hemisphere (from History of astronomy)
Image 33Sunset at the equinox from the prehistoric site of Pizzo Vento at Fondachelli Fantina, Sicily (from History of astronomy)
Image 34An 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 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 36Historical Jantar Mantar observatory in Jaipur, India (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 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. A planet can be an astronomical body that dynamically dominates its region (that is, whether it controls the fate of other smaller bodies in its vicinity) or it is defined to be in hydrostatic equilibrium (it has become gravitationally rounded and compacted). These may be characterized as the dynamical dominance definition and the geophysical definition. (Full article...)

List of featured articles

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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?

More Did you know facts

More Did you know (auto generated)

... 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 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 Michael Collins has been called "one of the best clarinettists walking the planet" by The Times?
... that the active galaxy 3C 120 was given the variable-star designation BW Tauri because of its variability in the visible spectrum?
... 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 the Passive Seismic Experiment Package recorded one of the first instances of humans littering on another planetary body?

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WikiProjects

WikiProject Astronomy	WikiProject Solar System



WikiProject Cosmology	WikiProject Spaceflight

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Credit: Digitized Sky Survey, ESA/ESO/NASA FITS Liberator

Orion's Belt or The Belt of Orion is an asterism in the constellation Orion. It consists of the three bright stars Alnitak, Alnilam, and Mintaka. The color picture was composited from photographic plates taken using the Samuel Oschin telescope at Palomar Observatory between 1987 and 1991.

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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)