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 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 the 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.

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...)

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The following are images from various astronomy-related articles on Wikipedia.

Image 1Ultra HD photography taken at La Silla Observatory (from Observational astronomy)
Image 2The main platform at La Silla hosts a huge range of telescopes with which astronomers can explore the Universe. (from Observational astronomy)
Image 3Sunset at the equinox from the prehistoric site of Pizzo Vento at Fondachelli Fantina, Sicily (from History of astronomy)
Image 4The 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 5Sir Patrick Moore was one of the world's leading popularisers of astronomy. (from Amateur astronomy)
Image 6Megaliths from Nabta Playa, constructed by Neolithic populations, located in Aswan, Upper Egypt. Excavations of the megalith structures were completed in 2008. (from History of astronomy)
Image 7The Hubble Space Telescope (from History of astronomy)
Image 8Artist 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 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 10Historical Jantar Mantar observatory in Jaipur, India (from History of astronomy)
Image 11An 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 12One 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 13Portrait of William Herschel, 1785 (from History of astronomy)
Image 14Places like Paranal Observatory offer crystal clear skies for observing astronomical objects with or without instruments. (from Amateur 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 16Mayall telescope at Kitt Peak National Observatory (from Observational astronomy)
Image 17Amateur astronomer recording observations of the sun. (from Amateur astronomy)
Image 18Arabic astrolabe from 1079 to 1080 AD (from History of astronomy)
Image 19This image contains two side-by-side pictures of the night sky comparing the effects of light pollution on the visibility of celestial objects. (from Amateur astronomy)
Image 20History 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 21An amateur astrophotography setup with an automated guide system connected to a laptop (from Observational astronomy)
Image 22A voting session is conducted in 2006 International Astronomical Union's general assembly for determining a new definition of a planet (from Astronomer)
Image 23Babylonian tablet in the British Museum recording Halley's Comet in 164 BC (from History of astronomy)
Image 24Overview of types of observational astronomy by observed wavelengths and their observability. (from Observational astronomy)
Image 25The Crab Nebula as seen in various wavelengths (from Observational astronomy)
Image 26A map of the southern celestial hemisphere, also by Bayer (from History of astronomy)
Image 27Comparison of CMB (Cosmic microwave background) results from satellites COBE, WMAP and Planck documenting a progress in 1989–2013 (from History of astronomy)
Image 28A map of the northern celestial hemisphere from Johann Bayer's 1661 edition of Uranometria, the first atlas to feature star charts covering the entire celestial sphere (from History of astronomy)
Image 29Segment 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 30An 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)
$Image 3150 cm refracting telescope at Nice Observatory (from Observational astronomy)$
Image 3150 cm refracting telescope at Nice Observatory (from Observational astronomy)
Image 32The Nebra sky disk, Germany, 1800–1600 BC (from History of astronomy)
Image 33"El Caracol" observatory temple at Chichen Itza, Mexico (from History of astronomy)
Image 34An assembly in Estonia to observe meteors (from Observational astronomy)
Image 35Calendrical functions of the Berlin Gold Hat c. 1000 BC (from History of astronomy)
Image 36ALMA is the world's most powerful telescope for studying the Universe at submillimeter and millimeter wavelengths. (from Observational astronomy)
Image 37Amateur astronomy groups are often involved in outreach to introduce astronomy to the general public (from Amateur astronomy)

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

The nebular hypothesis is the most widely accepted model in the field of cosmogony to explain the formation and evolution of the Solar System (as well as other planetary systems). It suggests the Solar System is formed from gas and dust orbiting the Sun which clumped up together to form the planets. The theory was developed by Immanuel Kant and published in his Universal Natural History and Theory of the Heavens (1755) and then modified in 1796 by Pierre Laplace. Originally applied to the Solar System, the process of planetary system formation is now thought to be at work throughout the universe. The widely accepted modern variant of the nebular theory is the solar nebular disk model (SNDM) or solar nebular model. It offered explanations for a variety of properties of the Solar System, including the nearly circular and coplanar orbits of the planets, and their motion in the same direction as the Sun's rotation. Some elements of the original nebular theory are echoed in modern theories of planetary formation, but most elements have been superseded.

According to the nebular theory, stars form in massive and dense clouds of molecular hydrogen—giant molecular clouds (GMC). These clouds are gravitationally unstable, and matter coalesces within them to smaller denser clumps, which then rotate, collapse, and form stars. Star formation is a complex process, which always produces a gaseous protoplanetary disk (proplyd) around the young star. This may give birth to planets in certain circumstances, which are not well known. Thus the formation of planetary systems is thought to be a natural result of star formation. A Sun-like star usually takes approximately 1 million years to form, with the protoplanetary disk evolving into a planetary system over the next 10–100 million years. (Full article...)

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... that Caroline Moore was 14 years old when she discovered supernova 2008ha?
... that although Charles Messier discovered the galaxy M91 in 1781, it was added to his catalogue only two centuries later?
... that the fall of the Neuschwanstein meteorite in 2002 was observed by the European Fireball Network and outdoor witnesses through most of Central Europe?
... that AG Pegasi has been described as the slowest nova ever recorded?

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... that the majority of extrasolar planets in fiction are inhabited by native species?
... that Kim Ye-ji's performance in the 10 meter air pistol at the 2024 Summer Olympics led her to be dubbed the "coolest person on the planet"?
... that some exoplanets are evaporating catastrophically?
... that in many works of fiction, the asteroid belt is the remnants of a destroyed planet?
... that Na drugą planetę, published in 1895 as one of the earliest Polish science-fiction novels, was later criticized by communist-era censors for its perceived "adoration for America"?
... that Michael Collins has been called "one of the best clarinettists walking the planet" by The Times?

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WikiProjects

More information WikiProject Astronomy, WikiProject Solar System ...

WikiProject Astronomy	WikiProject Solar System



WikiProject Cosmology	WikiProject Spaceflight

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Credit: Optical: NASA/HST/ASU/J. Hester et al. X-Ray: NASA/CXC/ASU/J. Hester et al.

The Crab Pulsar (PSR B0531+21) is a relatively young neutron star. The star is the central star in the Crab Nebula, a remnant of the supernova SN 1054, which was widely observed on Earth in the year 1054.

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Astronomy News

3 March 2026 –: Astronomers announce the discovery 1,900 light-years from Earth of TIC 120362137, the tightest known quadruple star system, using data from NASA's Transiting Exoplanet Survey Satellite. (Space.com)
10 December 2025 – Brazil–China relations: Brazil and China begin constructing a joint laboratory for radio astronomic technology with the Federal University of Campina Grande and the Federal University of Paraíba to support space research as both countries work on the BINGO radio telescope. (Reuters)

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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