Portal:Astronomy

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The Astronomy Portal

Introduction

Astronomy is a natural science that studies celestial objects and phenomena. It uses mathematics, physics, and chemistry in order to explain their origin and evolution. Objects of interest include planets, moons, stars, nebulae, galaxies, meteoroid, asteroid, 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 1Amateur astronomer recording observations of the sun. (from Amateur astronomy)
Image 2The Nebra sky disk, Germany, 1800 - 1600 BC (from History of astronomy)
Image 3Calendrical functions of the Berlin Gold Hat c. 1000 BC (from History of astronomy)
Image 4The Crab Nebula as seen in various wavelengths (from Observational astronomy)
Image 5Mayall telescope at Kitt Peak National Observatory (from Observational astronomy)
Image 6Historical accuracy of atomic clocks from NIST. (from Theoretical astronomy)
Image 7Hubble Space Telescope (from History of astronomy)
Image 8An assembly in Estonia to observe meteors (from Observational astronomy)
$Image 950 cm refracting telescope at Nice Observatory. (from Observational astronomy)$

Image 950 cm refracting telescope at Nice Observatory. (from Observational astronomy)
Image 10Portrait 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 11The Oort cloud, one of the most successful theoretical model about the Solar System (from Theoretical astronomy)
Image 12Places like Paranal Observatory offer crystal clear skies for observing astronomical objects with or without instruments. (from Amateur astronomy)
Image 13An amateur astrophotography setup with an automated guide system connected to a laptop. (from Observational astronomy)
Image 14Arabic astrolabe from 1079 to 1080 AD (from History of astronomy)
Image 159th-century diagram of the positions of the seven planets on 18 March 816, from the Leiden Aratea (from History of astronomy)
Image 16Babylonian tablet in the British Museum recording Halley's comet in 164 BC (from History of astronomy)
Image 17Sir Patrick Moore was one of the world's leading popularisers of astronomy. (from Amateur astronomy)
Image 18Segment 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 19Map 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 20One 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 21History 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 22Amateur astronomy groups are often involved in outreach in order to introduce astronomy to the general public (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 24The Antikythera Mechanism was an analog computer from 150 to 100 BC designed to calculate the positions of astronomical objects. (from History of astronomy)
Image 25Ultra HD photography taken at La Silla Observatory. (from Observational astronomy)
Image 26"El Caracol" observatory temple at Chichen Itza, Mexico (from History of astronomy)
Image 27The main platform at La Silla hosts a huge range of telescopes with which astronomers can explore the Universe. (from Observational astronomy)
Image 28Historical Jantar Mantar observatory in Jaipur, India (from History of astronomy)
Image 29Southern Hemisphere (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 31Sunset at the equinox from the prehistoric site of Pizzo Vento at Fondachelli Fantina, Sicily (from History of astronomy)
Image 32An 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 33Comparison of CMB (Cosmic microwave background) results from satellites COBE, WMAP and Planck documenting a progress in 1989–2013 (from History of astronomy)
Image 34A voting session is conducted in 2006 International Astronomical Union's general assembly for determining a new definition of a planet (from Astronomer)
Image 35Artist 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)

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

View of trailing hemisphere in natural color

Enceladus is the sixth-largest moon of Saturn (19th largest in the Solar System). It is about 500 kilometers (310 miles) in diameter, about a tenth of that of Saturn's largest moon, Titan. It is mostly covered by fresh, clean ice, making it one of the most reflective bodies of the Solar System. Consequently, its surface temperature at noon reaches only −198 °C (75.1 K; −324.4 °F), far colder than a light-absorbing body would be. Despite its small size, Enceladus has a wide range of surface features, ranging from old, heavily cratered regions to young, tectonically deformed terrain.

Enceladus was discovered on August 28, 1789 by William Herschel, but little was known about it until the two Voyager spacecraft, Voyager 1 and Voyager 2, flew by Saturn in 1980 and 1981. In 2005, the spacecraft Cassini started multiple close flybys of Enceladus, revealing its surface and environment in greater detail. In particular, Cassini discovered water-rich plumes venting from the south polar region. Cryovolcanoes near the south pole shoot geyser-like jets of water vapor, molecular hydrogen, other volatiles, and solid material, including sodium chloride crystals and ice particles, into space, totaling about 200 kilograms (440 pounds) per second. More than 100 geysers have been identified. Some of the water vapor falls back as "snow"; the rest escapes and supplies most of the material making up Saturn's E ring. According to NASA scientists, the plumes are similar in composition to comets. In 2014, NASA reported that Cassini had found evidence for a large south polar subsurface ocean of liquid water with a thickness of around 10 km (6 mi). The existence of Enceladus' subsurface ocean has since been mathematically modelled and replicated. (Full article...)

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Did you know - show different entries

... that British mathematician Margaret Meyer was the first woman to be elected to the Royal Astronomical Society?
... that the star cluster Messier 103 can be observed with the use of binoculars?
... that NASA has plans to tug an asteroid to the Moon?
... that MOA-2009-BLG-387Lb is the eleventh planet discovered using the gravitational microlensing phenomenon?
... that the first Dutch satellite, the Astronomical Netherlands Satellite, had the Main Belt asteroid 9996 ANS named after it?

More Did you know facts

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... that the Passive Seismic Experiment Package recorded one of the first instances of humans littering on another planetary body?
... that Jessen's icosahedron has been used for both the "Skwish" children's toy and a NASA proposal for a "super ball bot" to cushion space landers on other planets?
... 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 by naming her album Planet Her, Doja Cat was "just trying to be cute" and was not promoting a feminist agenda nor a planet exclusively for women?
... that Nandivada Rathnasree, who ran Delhi's planetarium, proposed that astronomers could be taught using India's stone-built observatories?
... that Mariner 1, the United States' first interplanetary probe, was lost in 1962 due to the miscoding of a single character in its software?

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WikiProjects

WikiProject Astronomy	WikiProject Solar System



WikiProject Cosmology	WikiProject Spaceflight

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Credit: NASA

Geodynamics of Venus as seen from a global radar view of the surface from Magellan probe radar imaging between 1990 and 1994. The age of Venus was revealed by the observation of over 900 impact craters on the surface of the planet.

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Astronomy News

14 June 2023 –: Astronomers report that the presence of phosphates on Enceladus, moon of the planet Saturn, has been detected, completing the discovery of all the basic chemical ingredients for life on the moon. (New York Times)
12 June 2023 – Discoveries of exoplanets: Astronomers announce in the journal Nature Astronomy the discovery of BEBOP-1c, an exoplanet orbiting the binary star system, TOI-1338. The system is the second discovered to have more than one circumbinary planet. (Space.com)
5 April 2023 – Discoveries of exoplanets: Scientists discover bursts of radiation in radio wavelengths on the exoplanet YZ Ceti b, which is part of the YZ Ceti system. The studies are published in the Nature Astronomy journal. (The Jerusalem Post)

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September anniversaries

5 September 1977 – Space probe Voyager 1 is launched on a mission to study Jupiter and Saturn
8 September 1966 – The first episode of a new television science fiction series "Star Trek" is shown on NBC-TV
12 September 2013 – NASA announces that 19 days earlier, Voyager 1 had become the first man-made object to cross the heliopause and enter interstellar space
15 September 2017 – The Cassini spacecraft plunges into the atmosphere of Saturn, ending its 13-year tour of the ringed planet
21 September 1866 – Science fiction writer, H. G. (Herbert George) Wells is born, in England
23 September 1846 – The planet Neptune is discovered by Johann Gottfried Galle using mathematical equations from John Couch Adams and Urbain Le Verrier
29 September 1971 – The Orbiting Solar Observatory 7 satellite launches with the first x-ray observations of a beginning solar flare and of solar streamers

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Space-related Portals

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Astronomical events

All times UT unless otherwise specified.

6 September, 11:03	Mercury at inferior conjunction
12 September, 15:42	Moon at apogee
15 September, 01:40	New moon
19 September, 09:54	Neptune at opposition
22 September, 12:59	Mercury at greatest western elongation
23 September, 06:50	Earth southward equinox
28 September, 01:05	Moon at perigee
29 September, 09:57	Full moon