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 1Ultra HD photography taken at La Silla Observatory (from Observational astronomy)
Image 2Babylonian tablet in the British Museum recording Halley's comet in 164 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 4Mayall telescope at Kitt Peak National Observatory (from Observational 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 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 7Portrait 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 8Sunset at the equinox from the prehistoric site of Pizzo Vento at Fondachelli Fantina, Sicily (from History of astronomy)
Image 9A voting session is conducted in 2006 International Astronomical Union's general assembly for determining a new definition of a planet (from Astronomer)
Image 10"El Caracol" observatory temple at Chichen Itza, Mexico (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 12An amateur astrophotography setup with an automated guide system connected to a laptop (from Observational astronomy)
Image 13Amateur astronomy groups are often involved in outreach in order to introduce astronomy to the general public (from Amateur astronomy)
Image 14An assembly in Estonia to observe meteors (from Observational astronomy)
Image 15Map 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 16Amateur astronomer recording observations of the sun. (from Amateur astronomy)
Image 17Southern Hemisphere (from History of astronomy)
Image 189th-century diagram of the positions of the seven planets on 18 March 816, from the Leiden Aratea (from History of astronomy)
Image 19The Antikythera Mechanism was an analog computer from 150 to 100 BC designed to calculate the positions of astronomical objects. (from History of astronomy)
Image 20The Oort cloud, one of the most successful theoretical model about the Solar System (from Theoretical astronomy)
$Image 2150 cm refracting telescope at Nice Observatory (from Observational astronomy)$

Image 2150 cm refracting telescope at Nice Observatory (from Observational astronomy)
Image 22Calendrical functions of the Berlin Gold Hat c. 1000 BC (from History of astronomy)
Image 23Historical Jantar Mantar observatory in Jaipur, India (from History of astronomy)
Image 24Overview of types of observational astronomy by observed wavelengths and their observability. (from Observational astronomy)
Image 25The main platform at La Silla hosts a huge range of telescopes with which astronomers can explore the Universe. (from Observational astronomy)
Image 26One 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 27Sir Patrick Moore was one of the world's leading popularisers of astronomy. (from Amateur astronomy)
Image 28Historical accuracy of atomic clocks from NIST. (from Theoretical astronomy)
Image 29Segment 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 30Comparison of CMB (Cosmic microwave background) results from satellites COBE, WMAP and Planck documenting a progress in 1989–2013 (from History of astronomy)
Image 31The Hubble Space Telescope (from History of astronomy)
Image 32ALMA is the world's most powerful telescope for studying the Universe at submillimeter and millimeter wavelengths. (from Observational astronomy)
Image 33The Crab Nebula as seen in various wavelengths (from Observational astronomy)
Image 34The Nebra sky disk, Germany, 1800 - 1600 BC (from History of astronomy)
Image 35Arabic astrolabe from 1079 to 1080 AD (from History of astronomy)
Image 36An 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)

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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 lenticular galaxy NGC 1553 is located at the center of the Dorado Group, and has a spiral feature that is only visible in X-rays?
... that giant diffuse galaxies, located in the centre of galaxy clusters, often possess a halo of devoured star matter extending as far out as 3 million light years?
... that the giant pulses of PSR B1937+21, the first discovered millisecond pulsar, are the brightest radio emission ever observed?
... that the star BX Circini is thought to have formed from the merger of two white dwarfs?
... that when astronomer Lacaille originally charted the constellation Caelum, it was recognized as an "engraver's chisel"?
... that the gamma-ray burst GRB 080319B was visible to the naked eye even though it was 7.5 billion light year away (z=0.937)?

More Did you know facts

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

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WikiProjects

WikiProject Astronomy	WikiProject Solar System



WikiProject Cosmology	WikiProject Spaceflight

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Credit: NASA / CXC / SAO (X-Ray) / NASA/JPL-Caltech (Infrared)

PSR B1509−58 is a pulsar approximately 17,000 light-years away in the constellation of Circinus discovered by the Einstein X-Ray Observatory in 1982. X-rays from Chandra are gold; infrared from WISE in red, green and blue/max.

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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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May anniversaries

1 May 1959 – The former Beltsville Center is renamed to Goddard Space Flight Center in honor of Dr. Robert H. Goddard, rocket pioneer who achieved first launch of a liquid-fueled rocket
4 May 1967 – Lunar Orbiter 4 is launched to perform a photographic survey of lunar surface features
7 May 1975 – Explorer 53 (SAS-C), a NASA X-ray astronomy space telescope, is launched from the San Marco Range in Kenya, Africa
7 May 1997 – English-language French science fiction action film, The Fifth Element is released showing passenger inter-constellation vehicles, spacefighter craft, and various non-human creatures
14 May 1935 – The planetarium at Griffith Observatory in Los Angeles, California opens
14 May 1973 – The first American space station, Skylab, is launched
18 May 1969 – The Apollo 10 human spaceflight is launched, testing all aspects of the lunar landing mission, except the actual lunar landing
20 May 1978 – Pioneer Venus is launched from Cape Canaveral, Florida becoming the first spacecraft placed in orbit around Venus
30 May 1971 – Mariner 9 robotic space probe is launched becoming the first spacecraft to orbit Mars