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 1Historical accuracy of atomic clocks from NIST. (from Theoretical astronomy)
Image 2The Oort cloud, one of the most successful theoretical model about the Solar System (from Theoretical astronomy)
Image 3The Hubble Space Telescope (from History of astronomy)
Image 4The Crab Nebula as seen in various wavelengths (from Observational astronomy)
Image 5Historical Jantar Mantar observatory in Jaipur, India (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 79th-century diagram of the positions of the seven planets on 18 March 816, from the Leiden Aratea (from History of astronomy)
Image 8An assembly in Estonia to observe meteors (from Observational astronomy)
Image 9Segment 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 10Amateur astronomy groups are often involved in outreach to introduce astronomy to the general public (from Amateur astronomy)
Image 11Map 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 12History 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 13Places like Paranal Observatory offer crystal clear skies for observing astronomical objects with or without instruments. (from Amateur astronomy)
Image 14A voting session is conducted in 2006 International Astronomical Union's general assembly for determining a new definition of a planet (from Astronomer)
Image 15Sir Patrick Moore was one of the world's leading popularisers of astronomy. (from Amateur astronomy)
Image 16An amateur astrophotography setup with an automated guide system connected to a laptop (from Observational astronomy)
Image 17Arabic astrolabe from 1079 to 1080 AD (from History of astronomy)
Image 18ALMA is the world's most powerful telescope for studying the Universe at submillimeter and millimeter wavelengths. (from Observational astronomy)
Image 19The Nebra sky disk, Germany, 1800–1600 BC (from History of astronomy)
Image 20Overview of types of observational astronomy by observed wavelengths and their observability. (from Observational astronomy)
Image 21One 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 22An 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 23The main platform at La Silla hosts a huge range of telescopes with which astronomers can explore the Universe. (from Observational astronomy)
Image 24Sunset at the equinox from the prehistoric site of Pizzo Vento at Fondachelli Fantina, Sicily (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)
$Image 2650 cm refracting telescope at Nice Observatory (from Observational astronomy)$

Image 2650 cm refracting telescope at Nice Observatory (from Observational astronomy)
Image 27Portrait 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 28Amateur astronomer recording observations of the sun. (from Amateur astronomy)
Image 29Ultra HD photography taken at La Silla Observatory (from Observational astronomy)
Image 30Mayall telescope at Kitt Peak National Observatory (from Observational astronomy)
Image 31The 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 32Babylonian tablet in the British Museum recording Halley's Comet in 164 BC (from History of astronomy)
Image 33The Antikythera Mechanism was an analog computer from 150 to 100 BC designed to calculate the positions of astronomical objects. (from History of astronomy)
Image 34"El Caracol" observatory temple at Chichen Itza, Mexico (from History of astronomy)
Image 35Calendrical functions of the Berlin Gold Hat c. 1000 BC (from History of astronomy)
Image 36Southern 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.

Titan, imaged by the Cassini orbiter, December 2011. A thick shroud of organic haze permanently obscures Titan's surface from viewing in visible light

Titan is the largest moon of Saturn and the second-largest in the Solar System. It is the only moon known to have an atmosphere denser than the Earth's and is the only known object in space—other than Earth—on which clear evidence of stable bodies of surface liquid has been found. Titan is one of seven gravitationally rounded moons of Saturn and the second-most distant among them. Frequently described as a planet-like moon, Titan is 50% larger in diameter than Earth's Moon and 80% more massive. It is the second-largest moon in the Solar System after Jupiter's Ganymede and is larger than Mercury, but only 40% as massive due to the latter being composed mainly of dense iron and rock, while a large portion of Titan is less-dense ice.

Discovered in 1655 by the Dutch astronomer Christiaan Huygens, Titan was the first known moon of Saturn and the sixth known planetary satellite (after Earth's moon and the four Galilean moons of Jupiter). Titan orbits Saturn at 20 Saturn radii or 1,200,000 km above Saturn's apparent surface. From Titan's surface, Saturn subtends an arc of 5.09 degrees, and if it were visible through the moon's thick atmosphere, it would appear 11.4 times larger in the sky, in diameter, than the Moon from Earth, which subtends 0.48° of arc. (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?

More Did you know facts

More Did you know (auto generated)

... that Michael Collins has been called "one of the best clarinettists walking the planet" by The Times?
... 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 in early depictions of Uranus in fiction, the planet was portrayed as solid
... that examples of artificial planets in science fiction include Riverworld, the Well World, and the Death Star?
... that the Passive Seismic Experiment Package recorded one of the first instances of humans littering on another planetary body?
... that Susan Murabana created Africa's first permanent planetarium?

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WikiProjects

WikiProject Astronomy	WikiProject Solar System



WikiProject Cosmology	WikiProject Spaceflight

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Selected image - show another

Credit: NASA

IC 443 (also known as the Jellyfish Nebula and Sharpless 248 (Sh2-248)) is a galactic supernova remnant (SNR) in the constellation Gemini. Its distance is roughly 5,000 light years from Earth. Image is part of the northeastern shell of IC 443, aka the Jellyfish Nebula.

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Astronomy News

15 July 2024 – Mare Tranquillitatis pit: In the journal Nature Astronomy, American and Italian scientists announce the discovery of a lunar cave, approximately 250 miles (400 km) from the landing site of Apollo 11. (AP) (Nature Astronomy)
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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July anniversaries

1 July 2004 – The Cassini spacecraft arrives at Saturn after entering orbit
4 July 1997 – Mars Pathfinder and its rover, Sojourner, land on Mars, with the latter becoming the first rover to successfully travel the planet
5 July 1687 – Sir Isaac Newton's Philosophiæ Naturalis Principia Mathematica, which formulated the laws of motion and universal gravitation and applied them to celestial bodes, is first published
13 July 2007 – Gran Telescopio Canarias undergoes first light, becoming the largest telescope in the world
20 July 1969 – As part of the Apollo 11 mission, Americans Neil Armstrong and Buzz Aldrin become the first men to walk on the Moon
20 July 1976 – Viking 1 becomes the first spacecraft to successfully land on Mars and perform its mission
26 July 1971 – Apollo 15 launches with lunar rover payload

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Space-related Portals

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Astronomical events

All times UT unless otherwise specified.

5 July, 05:59	Earth at aphelion
5 July, 22:57	New moon
12 July, 08:12	Moon at apogee
21 July, 10:17	Full moon
22 July, 06:59	Mercury at greatest eastern elongation
24 July, 05:43	Moon at perigee
24 July, 20:47	Moon occults Saturn
25 July, 15:01	Moon occults Neptune
27 July, 21:44	Southern Delta Aquariids peak