Portal:Astronomy
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...)
General images -
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A map of the southern celestial hemisphere, also by Bayer (from History of astronomy) -
The Nebra sky disk, Germany, 1800–1600 BC (from History of astronomy) -
Portrait of William Herschel, 1785 (from History of astronomy) -
50 cm refracting telescope at Nice Observatory (from Observational astronomy) -
Arabic astrolabe from 1079 to 1080 AD (from History of astronomy) -
Sunset at the equinox from the prehistoric site of Pizzo Vento at Fondachelli Fantina, Sicily (from History of astronomy) -
The 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) -
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One 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) -
ALMA is the world's most powerful telescope for studying the Universe at submillimeter and millimeter wavelengths. (from Observational astronomy) -
Artist 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) -
A voting session is conducted in 2006 International Astronomical Union's general assembly for determining a new definition of a planet (from Astronomer) -
A 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) -
Ultra HD photography taken at La Silla Observatory (from Observational astronomy) -
An 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) -
The main platform at La Silla hosts a huge range of telescopes with which astronomers can explore the Universe. (from Observational astronomy) -
Segment 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) -
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Overview of types of observational astronomy by observed wavelengths and their observability. (from Observational astronomy) -
Calendrical functions of the Berlin Gold Hat c. 1000 BC (from History of astronomy) -
Map 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) -
Amateur astronomer recording observations of the sun. (from Amateur astronomy) -
An amateur astrophotography setup with an automated guide system connected to a laptop (from Observational astronomy) -
9th-century diagram of the positions of the seven planets on 18 March 816, from the Leiden Aratea (from History of astronomy) -
An 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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Sir Patrick Moore was one of the world's leading popularisers of astronomy. (from Amateur astronomy) -
Amateur astronomy groups are often involved in outreach to introduce astronomy to the general public (from Amateur astronomy) -
The Hubble Space Telescope (from History of astronomy) -
Babylonian tablet in the British Museum recording Halley's Comet in 164 BC (from History of astronomy) -
History of the Universe – gravitational waves are hypothesized to arise from cosmic inflation, a rapidly accelerated expansion just after the Big Bang (from Physical cosmology) -
Places like Paranal Observatory offer crystal clear skies for observing astronomical objects with or without instruments. (from Amateur astronomy) -
Comparison of CMB (Cosmic microwave background) results from satellites COBE, WMAP and Planck documenting a progress in 1989–2013 (from History of astronomy) -
The Crab Nebula as seen in various wavelengths (from Observational astronomy) -
Megaliths 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) -
This 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)
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Featured article -
A white dwarf is a very dense type of star: in an Earth-sized volume, it packs a mass that is comparable to the Sun. A white dwarf radiates light from residual heat, not from nuclear fusion. Stars like the Sun, whose mass is not high enough to collapse into a neutron star or black hole, are expected to become white dwarf stars later in their evolution. The nearest known white dwarf is Sirius B, at 8.6 light years, the smaller component of the Sirius binary star.
In 1910, Henry Norris Russell, Edward Charles Pickering and Williamina Fleming discovered that, despite being a dim star, 40 Eridani B was of spectral type A, or white. This would become known as the first white dwarf. The name white dwarf was coined by Willem Jacob Luyten in 1922. In 1931 Subrahmanyan Chandrasekhar developed a physical model of white dwarfs and he won the 1983 Nobel Prize in Physics for studies in the evolution of stars. (Full article...)
Did you know -
- ... that the asteroid 2011 XC2 missed the Earth by less than 1 lunar distance on 3 December 2011?
- ... that the mass-luminosity relation, first derived by Arthur Eddington in 1924, helps astronomers find the distances to binary star systems?
- ... that the planetary nebula Abell 39 is unusually spherical, yet its central star is offset from the center?
- ... that data from Mariner 10 led to the discovery of Mercury's magnetic field in 1974?
- ... that the Toronto Magnetic Observatory had to be moved as the University of Toronto's electric lighting was interfering with observations?
More Did you know (auto generated)
- ... that some exoplanets are evaporating catastrophically?
- ... that the majority of extrasolar planets in fiction are inhabited by native species?
- ... that scientists have discovered a planetary system that can be described as "inside-out"?
- ... that 1ES 1927+654, a galaxy in Draco, exhibited such extreme nuclear activity that it challenged conventional models of black-hole environments?
- ... that examples of artificial planets in science fiction include Riverworld, the Well World, and the Death Star?
- ... that fictional planets of the Solar System include planets between Venus and Earth, planets on the inside of a hollow Earth, and a planet "behind the Earth"?
WikiProjects
Selected image -
A Type II supernova (plural: supernovae or supernovas) results from the rapid collapse and violent explosion of a massive star. Image is the expanding remnant of SN 1987A, a Type II-P supernova in the Large Magellanic Cloud.
Astronomy News
2026 in space | |||
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- 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)
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
Space-related Portals
Astronomical events
All times UT unless otherwise specified. Portal:Astronomy/Events/May 2026
Topics
Subcategories
Things you can do
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Astronomy articles for which peer review has been requested:
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Wikibooks
These books may be in various stages of development. See also the related Science and Mathematics bookshelves.
- Astronomy
- GAT: A Glossary of Astronomical Terms
- Introduction to Astrophysics
- General relativity
- Observing the Sky from 30°S
- Observing the Sky from 40°N
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