Portal:Astronomy

Portal topics: Activities; Culture; Geography; Health; History; Mathematics; Nature; People; Philosophy; Religion; Society; Technology; Random portal

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.

$Image 150 cm refracting telescope at Nice Observatory (from Observational astronomy)$

Image 150 cm refracting telescope at Nice Observatory (from Observational astronomy)
Image 2Amateur astronomer recording observations of the sun. (from Amateur astronomy)
Image 3Places like Paranal Observatory offer crystal clear skies for observing astronomical objects with or without instruments. (from Amateur astronomy)
Image 4History 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 5The 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 69th-century diagram of the positions of the seven planets on 18 March 816, from the Leiden Aratea (from History of astronomy)
Image 7An 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 8Ultra HD photography taken at La Silla Observatory (from Observational astronomy)
Image 9Amateur astronomy groups are often involved in outreach in order to introduce astronomy to the general public (from Amateur 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 11An amateur astrophotography setup with an automated guide system connected to a laptop (from Observational astronomy)
Image 12A voting session is conducted in 2006 International Astronomical Union's general assembly for determining a new definition of a planet (from Astronomer)
Image 13Historical Jantar Mantar observatory in Jaipur, India (from History of astronomy)
Image 14ALMA is the world's most powerful telescope for studying the Universe at submillimeter and millimeter wavelengths. (from Observational astronomy)
Image 15Babylonian tablet in the British Museum recording Halley's comet in 164 BC (from History of 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 17Sunset at the equinox from the prehistoric site of Pizzo Vento at Fondachelli Fantina, Sicily (from History of 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 19Overview of types of observational astronomy by observed wavelengths and their observability. (from Observational astronomy)
Image 20Historical accuracy of atomic clocks from NIST. (from Theoretical astronomy)
Image 21The main platform at La Silla hosts a huge range of telescopes with which astronomers can explore the Universe. (from Observational astronomy)
Image 22The Hubble Space Telescope (from History of astronomy)
Image 23Artist 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 24Arabic astrolabe from 1079 to 1080 AD (from History of astronomy)
Image 25The Crab Nebula as seen in various wavelengths (from Observational astronomy)
Image 26Sir Patrick Moore was one of the world's leading popularisers of astronomy. (from Amateur astronomy)
Image 27The Antikythera Mechanism was an analog computer from 150 to 100 BC designed to calculate the positions of astronomical objects. (from History of astronomy)
Image 28Mayall telescope at Kitt Peak National Observatory (from Observational astronomy)
Image 29"El Caracol" observatory temple at Chichen Itza, Mexico (from History of astronomy)
Image 30One 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 31The Oort cloud, one of the most successful theoretical model about the Solar System (from Theoretical astronomy)
Image 32The Nebra sky disk, Germany, 1800 - 1600 BC (from History of astronomy)
Image 33Map 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 34Calendrical functions of the Berlin Gold Hat c. 1000 BC (from History of astronomy)
Image 35Southern Hemisphere (from History of astronomy)
Image 36An assembly in Estonia to observe meteors (from Observational astronomy)

Refresh with new selections below (purge)

Featured article - show another

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

Absorption lines in the visible spectrum of a supercluster of distant galaxies (right), as compared to absorption lines in the visible spectrum of the Sun (left). Arrows indicate redshift. Wavelength increases up towards the red and beyond (frequency decreases).

In physics, a redshift is an increase in the wavelength, and corresponding decrease in the frequency and photon energy, of electromagnetic radiation (such as light). The opposite change, a decrease in wavelength and increase in frequency and energy, is known as a blueshift, or negative redshift. The terms derive from the colours red and blue which form the extremes of the visible light spectrum. The main causes of electromagnetic redshift in astronomy and cosmology are the relative motions of radiation sources, which give rise to the relativistic Doppler effect, and gravitational potentials, which gravitationally redshift escaping radiation. All sufficiently distant light sources show cosmological redshift corresponding to recession speeds proportional to their distances from Earth, a fact known as Hubble's law that implies the universe is expanding.

All redshifts can be understood under the umbrella of frame transformation laws. Gravitational waves, which also travel at the speed of light, are subject to the same redshift phenomena. The value of a redshift is often denoted by the letter

z

, corresponding to the fractional change in wavelength (positive for redshifts, negative for blueshifts), and by the wavelength ratio

1 + z

(which is greater than 1 for redshifts and less than 1 for blueshifts). (Full article...)

List of featured articles

edit

Did you know - show different entries

... that 12th-century Muslim scientist Al-Khazini, who proposed a theory of gravitation long before Isaac Newton, was, in his early life, a slave of the Seljuq Turks?
... that Kepler-47c is a circumbinary planet orbiting in the habitable zone of Kepler-47, a binary star system?
... that two high school students used the automated telescope at Leuschner Observatory to record the earliest images of supernova SN 1994I?
... that the Kuiper crater in the Kuiper quadrangle, named after Dutch American astronomer Gerard Kuiper, has the highest albedo recorded on Mercury?
...that Mt. Olympus Mons on Mars is the highest peak in the solar system?

More Did you know facts

More Did you know (auto generated)

... that Nandivada Rathnasree, who ran Delhi's planetarium, proposed that astronomers could be taught using India's stone-built observatories?
... that it took five years of observations to find the planet orbiting the star HD 175167?
... that in early depictions of Uranus in fiction, the planet was portrayed as solid
... that pushbacks of migrants in the Aegean Sea have been described as "a human rights violation that encapsulates a will to eliminate a person's presence on the face of the planet"?
... 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)?
... 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?

edit

WikiProjects

WikiProject Astronomy	WikiProject Solar System



WikiProject Cosmology	WikiProject Spaceflight

edit

Selected image - show another

Credit: Kevin Heider @ LightBuckets

Active asteroids are small Solar System bodies that have asteroid-like orbits but show comet-like visual characteristics. Image of asteroid (596) Scheila displaying a comet-like appearance on December 12, 2010.

More selected pictures

Read more

edit

Astronomy News

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)
24 November 2023 –: Astronomers at the Telescope Array Project in Utah, United States, observe the second largest cosmic ray ever detected, the so-called Amaterasu particle, with an energy of 244 EeV. (Cosmos Magazine)

edit

April anniversaries

2 April 1968 – The epic science fiction film, 2001: A Space Odyssey is released
3 April 2014 – NASA announces that the Cassini orbiter has found evidence of an underground body of water on Enceladus, a moon of Saturn
7 April 2001 – Mars Odyssey orbiter is launched to map and search for water on Mars
12 April 1961 – Cosmonaut Yuri Gagarin becomes the first human to enter outer space when he is launched into orbital flight in Vostok 1
19 April 1971 – The first space station, Salyut 1, is launched into orbit
24 April 1990 – The Hubble Space Telescope, a powerful research tool and public relations boon for astronomy, is launched into orbit

More anniversaries

edit

Space-related Portals

edit

Astronomical events

All times UT unless otherwise specified.

6 April, 09:25	Moon occults Saturn
7 April, 08:11	Moon occults Neptune
7 April, 16:47	Moon occults Venus
7 April, 17:53	Moon at perigee
8 April, 18:18	New moon and Total Solar Eclipse
11 April, 22:53	Mercury at inferior conjunction
20 April, 02:09	Moon at apogee
22 April, 06:44	Lyrids peak
23 April, 23:49	Full moon