Portal:Astronomy

The Astronomy Portal Introduction Astronomy (from Greek: ἀστρονομία, literally meaning the science that studies the laws of the stars) 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, 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 outside Earth's atmosphere. Cosmology is a branch of astronomy. It 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 Babylonians, Greeks, Indians, Egyptians, 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. Nowadays, professional astronomy is often said to be the same as astrophysics. 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...) Featured article - This is a Featured article, which represents some of the best content on English Wikipedia.. Tau Ceti, Latinized from τ Ceti, is a single star in the constellation Cetus that is spectrally similar to the Sun, although it has only about 78% of the Sun's mass. At a distance of just under 12 light-years (3.7 parsecs) from the Solar System, it is a relatively nearby star and the closest solitary G-class star. The star appears stable, with little stellar variation, and is metal-deficient. Observations have detected more than ten times as much dust surrounding Tau Ceti as is present in the Solar System. Since December 2012, there has been evidence of at least four planets—all confirmed being super-Earths—orbiting Tau Ceti, with two of these being potentially in the habitable zone. There are an additional four unconfirmed planets, one of which is a Jovian planet between 3 and 20 AU from the star. Because of its debris disk, any planet orbiting Tau Ceti would face far more impact events than Earth. Despite this hurdle to habitability, its solar analog (Sun-like) characteristics have led to widespread interest in the star. Given its stability, similarity and relative proximity to the Sun, Tau Ceti is consistently listed as a target for the Search for Extra-Terrestrial Intelligence (SETI) and appears in some science fiction literature. (Full article...) List of featured articles Vega GRB 970508 Titan (moon) Definition of planet Ariel (moon) Umbriel (moon) Triton (moon) Big Bang Transit of Venus Cat's Eye Nebula Apollo 8 Kreutz sungrazer Astrophysics Data System Comet Shoemaker–Levy 9 Sun Mercury (planet) Io (moon) Comet Hale–Bopp Hubble Deep Field H II region Barnard's Star Globular cluster Solar System Mars Hubble Space Telescope Galaxy Johannes Kepler Kuiper belt Herbig–Haro object Enceladus Callisto (moon) Scattered disc Venus IK Pegasi White dwarf General relativity Redshift Atmosphere of Jupiter Zhang Heng Supernova Rings of Uranus Gamma-ray burst Saturn Nebular hypothesis GRB 970508 243 Ida Eris (dwarf planet) Main sequence Star Andromeda (constellation) Proxima Centauri Did you know - ... 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? Subcategories Select [►] to view subcategories ▼ Astronomy ► Astronomy by location ► Astronomical objects ► Astronomical sub-disciplines ► Astronomy-related lists ► Outer space ► Space art ► Astrology ► Astronomers ► Astronomical controversies ► Astronomical hypotheses ► Celestial coordinate system ► Celestial navigation ► Astronomical classification systems ► Astronomical clocks ► Constellations ► Cosmogony ► Cultural depictions of astronomers ► Dark-sky preserves ► Astronomy data and publications ► Astronomical dynamical systems ► Astronomy education ► Astronomical events ► Astronomy events ► History of astronomy ► Astronomical instruments ► Astronomical myths ► Astronomy organizations ► People associated with astronomy ► Philosophy of astronomy ► Astronomy prizes ► Astronomy projects ► Pseudoastronomers ► Sky regions ► Space telescopes ► Astronomical symbols ► Time in astronomy ► Units of measurement in astronomy ► Unsolved problems in astronomy ► Works about astronomy ► Wikipedia books on astronomy ► Astronomy stubs WikiProjects WikiProject Astronomy WikiProject Solar System WikiProject Cosmology WikiProject Spaceflight Selected image - NGC 1300 is a barred spiral galaxy about 61 million light-years away in the constellation Eridanus. The galaxy is about 110,000 light-years across; just slightly larger than our own galaxy, the Milky Way. Astronomy News See also: 2021 in science 1 January 1925 – Astronomer Edwin Hubble formally presents his discovery of galaxies outside the Milky Way at a meeting of the American Astronomical Society 3 January 1888 – The 91-centimeter refracting telescope at Lick Observatory, the world's largest telescope from 1888 to 1897, sees its first light 4 January 2004 – The Mars rover Spirit lands, three weeks ahead of twin rover Opportunity, and begins exploring the Red Planet 14 January 2005 – The probe Huygens lands on Titan, a moon of Saturn, in the first successful landing in the outer Solar System 26 January 1949 – Hale telescope, which introduced several innovations to telescope construction and was the world's largest telescope for nearly 30 years, has its first light 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 Wikijunior Solar System All times UT unless otherwise specified. 2 January, 08:59 Earth at perihelion 3 January, 14:47 Quadrantids peak 9 January, 15:39 Moon at perigee 13 January, 05:00 New moon 21 January, 13:11 Moon at apogee 24 January, 01:59 Mercury at greatest eastern elongation 24 January, 02:26 Saturn at conjunction 28 January, 19:16 Full moon 29 January, 00:51 Jupiter at conjunction Celestial events by month Portals : Astronomy and Outer space 2021: January | February | March | April | May | June | July | August | September | October | November | December 2020: January | February | March | April | May | June | July | August | September | October | November | December 2019: January | February | March | April | May | June | July | August | September | October | November | December 2018: January | February | March | April | May | June | July | August | September | October | November | December 2017: January | February | March | April | May | June | July | August | September | October | November | December 2016: January | February | March | April | May | June | July | August | September | October | November | December 2015: January | February | March | April | May | June | July | August | September | October | November | December 2014: January | February | March | April | May | June | July | August | September | October | November | December 2013: January | February | March | April | May | June | July | August | September | October | November | December 2012: January | February | March | April | May | June | July | August | September | October | November | December 2011: January | February | March | April | May | June | July | August | September | October | November | December 2010: January | February | March | April | May | June | July | August | September | October | November | December 2009: January | February | March | April | May | June | July | August | September | October | November | December 2008: January | February | March | April | May | June | July | August | September | October | November | December 2007: January | February | March | April | May | June | July | August | September | October | November | December 2006: January | February | March | April | May | June | July | August | September | October | November | December 2005: January | February | March | April | May | June | July | August | September | October | November | December Here are some Open Tasks : Copyedit: More... 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