Portal:Astronomy

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 1An 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 2The 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 39th-century diagram of the positions of the seven planets on 18 March 816, from the Leiden Aratea (from History of astronomy)
Image 4An example of a gravitational lens found in the DESI Legacy Surveys data. There are four sets of lensed images in DESI-090.9854-35.9683, corresponding to four distinct background galaxies—from the outermost giant red arc to the innermost bright blue arc, arranged in four concentric circles. All of them are gravitationally warped—or lensed—by the orange galaxy at the very center. Dark matter is expected to produce gravitational lensing also. (from Physical cosmology)
Image 5Sir Patrick Moore was one of the world's leading popularisers of astronomy. (from Amateur astronomy)
$Image 650 cm refracting telescope at Nice Observatory (from Observational astronomy)$

Image 650 cm refracting telescope at Nice Observatory (from Observational astronomy)
Image 7The Crab Nebula as seen in various wavelengths (from Observational astronomy)
Image 8Southern Hemisphere (from History of astronomy)
Image 9Arabic astrolabe from 1079 to 1080 AD (from History of astronomy)
Image 10Sunset at the equinox from the prehistoric site of Pizzo Vento at Fondachelli Fantina, Sicily (from History of astronomy)
Image 11"El Caracol" observatory temple at Chichen Itza, Mexico (from History of astronomy)
Image 12An amateur astrophotography setup with an automated guide system connected to a laptop (from Observational astronomy)
Image 13Overview of types of observational astronomy by observed wavelengths and their observability. (from Observational astronomy)
Image 14Segment 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 15The Oort cloud, one of the most successful theoretical models about the Solar System (from Theoretical astronomy)
Image 16Comparison of CMB (Cosmic microwave background) results from satellites COBE, WMAP and Planck documenting a progress in 1989–2013 (from History of astronomy)
Image 17The Nebra sky disk, Germany, 1800–1600 BC (from History of astronomy)
Image 18The inflationary theory as an augmentation to the Big Bang theory was first proposed by Alan Guth of MIT. Inflation solves the 'horizon problem' by making the early universe much more compact than was assumed in the standard model. Given such smaller size, causal contact (i.e., thermal communication) would have been possible among all regions of the early universe. The image was an adaptation from various generic charts depicting the growth of the size of the observable universe, for both the standard model and inflationary model respectively, of the Big Bang theory. (from Physical cosmology)
Image 19History 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 20Artist 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 21Places like Paranal Observatory offer crystal clear skies for observing astronomical objects with or without instruments. (from Amateur astronomy)
Image 22Historical accuracy of atomic clocks from NIST. (from Theoretical astronomy)
Image 23Portrait 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 24Amateur astronomer recording observations of the sun. (from Amateur astronomy)
Image 25Mayall telescope at Kitt Peak National Observatory (from Observational astronomy)
Image 26The Hubble Space Telescope (from History of astronomy)
Image 27ALMA is the world's most powerful telescope for studying the Universe at submillimeter and millimeter wavelengths. (from Observational astronomy)
Image 28Amateur astronomy groups are often involved in outreach to introduce astronomy to the general public (from Amateur astronomy)
Image 29Ultra HD photography taken at La Silla Observatory (from Observational astronomy)
Image 30An assembly in Estonia to observe meteors (from Observational astronomy)
Image 31The main platform at La Silla hosts a huge range of telescopes with which astronomers can explore the Universe. (from Observational astronomy)
Image 32Babylonian tablet in the British Museum recording Halley's Comet in 164 BC (from History of astronomy)
Image 33One 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 34Calendrical functions of the Berlin Gold Hat c. 1000 BC (from History of astronomy)
Image 35A voting session is conducted in 2006 International Astronomical Union's general assembly for determining a new definition of a planet (from Astronomer)
Image 36Map 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 37Historical Jantar Mantar observatory in Jaipur, India (from History of astronomy)

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

Vega is the brightest star in the northern constellation of Lyra. It has the Bayer designation α Lyrae, which is Latinised to Alpha Lyrae and abbreviated Alpha Lyr or α Lyr. This star is relatively close at only 25 light-years (7.7 parsecs) from the Sun, and one of the most luminous stars in the Sun's neighborhood. It is the fifth-brightest star in the night sky, and the second-brightest star in the northern celestial hemisphere, after Arcturus.

Vega has been extensively studied by astronomers, leading it to be termed "arguably the next most important star in the sky after the Sun". Vega was the northern pole star around 12,000 BCE and will be so again around the year 13,727, when its declination will be +86° 14′. Vega was the first star other than the Sun to have its image and spectrum photographed. It was one of the first stars whose distance was estimated through parallax measurements. Vega has functioned as the baseline for calibrating the photometric brightness scale and was one of the stars used to define the zero point for the UBV photometric system. (Full article...)

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Did you know - show different entries

... that Oscar Monnig donated one of the largest private collections of meteorites to Texas Christian University?
... that at first light in 1987, the William Herschel Telescope was the third largest single optical telescope in the world, and is still the second largest in Europe?
... that a Bok globule is a dark cloud of dense dust and gas, first observed by astronomer Bart Bok in the 1940s, in which star formation is taking place within the H II region?
... that the aerial telescope is a type of very long focal length refracting telescope built in the second half of the 17th century that did not use a tube?
... that the galaxy pair Arp 147 contains a ring of nine black holes?

More Did you know facts

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... that the galaxy NGC 1700 has a rotating hot gas disk glowing in X-rays after merging with another galaxy three billion years ago?
... that the active galaxy 3C 120 was given the variable-star designation BW Tauri because of its variability in the visible spectrum?
... that novelist Hal Clement created the planet Mesklin in 1953 based on the real-world suspected detection of an extrasolar planet?
... 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 1ES 1927+654, a galaxy in Draco, exhibited such extreme nuclear activity that it challenged conventional models of black-hole environments?
... 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)?

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WikiProjects

WikiProject Astronomy	WikiProject Solar System



WikiProject Cosmology	WikiProject Spaceflight

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Credit: NASA Earth Observatory / STEREO Science Center

A coronal mass ejection (CME) is a significant release of plasma and accompanying magnetic field from the solar corona. They often follow solar flares and are normally present during a solar prominence eruption. Coronal mass ejections release large quantities of matter and electromagnetic radiation into space above the Sun's surface, either near the corona, or farther into the planetary system, or beyond (interplanetary CME).

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Astronomy News

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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)

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Space-related Portals

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Astronomical events

All times UT unless otherwise specified.

1 June, 01:59	Venus at greatest western elongation
7 June, 10:42	Moon at apogee
11 June, 07:44	Full moon
21 June, 02:42	Earth northern solstice
23 June, 04:43	Moon at perigee
24 June, 15:06	Jupiter at conjunction; occultation
25 June, 10:31	New moon
30 June, 01:05	Moon occults Mars