Portal:Astronomy
Introduction
19th-century Quito Astronomical Observatory is located 12 minutes south of the Equator in Quito, Ecuador.
X-ray jet made from a supermassive black hole found by NASA's Chandra X-ray Observatory, made visible by light from the early Universe
The Very Large Array in New Mexico, an example of a radio telescope
Greek equatorial sundial, Alexandria on the Oxus, present-day Afghanistan 3rd–2nd century BCE
A celestial map from the 17th century, by the Dutch cartographer Frederik de Wit
Amateur astronomers can build their own equipment, and hold star parties and gatherings, such as Stellafane.
ALMA Observatory is one of the highest observatory sites on Earth. Atacama, Chile.
Star cluster Pismis 24 with a nebula
Solar observatory Lomnický štít (Slovakia) built in 1962
An ultraviolet image of the Sun's active photosphere as viewed by the TRACE space telescope. NASA photo
Observed structure of the Milky Way's spiral arms
An astronomical chart from an early scientific manuscript, c. 1000
The Milky Way as viewed from La Silla Observatory
The Subaru Telescope (left) and Keck Observatory (center) on Mauna Kea, both examples of an observatory that operates at near-infrared and visible wavelengths. The NASA Infrared Telescope Facility (right) is an example of a telescope that operates only at near-infrared wavelengths.
Mz 3, often referred to as the Ant planetary nebula. Ejecting gas from the dying central star shows symmetrical patterns unlike the chaotic patterns of ordinary explosions.
19th-century Sydney Observatory, Australia (1873)
The black spot at the top is a dust devil climbing a crater wall on Mars. This moving, swirling column of Martian atmosphere (comparable to a terrestrial tornado) created the long, dark streak. NASA image.
This image shows several blue, loop-shaped objects that are multiple images of the same galaxy, duplicated by the gravitational lens effect of the cluster of yellow galaxies near the middle of the photograph. The lens is produced by the cluster's gravitational field that bends light to magnify and distort the image of a more distant object.
A giant Hubble mosaic of the Crab Nebula, a supernova remnant
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Astronomy (from Greek: ἀστρονομία) is a natural science that studies celestial objects and phenomena. It applies mathematics, physics, and chemistry in an effort to explain the origin of those objects and phenomena and their evolution. Objects of interest include planets, moons, stars, nebulae, galaxies, and comets; the phenomena also includes supernova explosions, gamma ray bursts, quasars, blazars, pulsars, and cosmic microwave background radiation. More generally, all phenomena that originate outside Earth's atmosphere are within the purview of astronomy. A related but distinct subject is physical cosmology, which is the study of the Universe as a whole.
Astronomy is one of the oldest of the natural sciences. The early civilizations in recorded history, such as the Babylonians, Greeks, Indians, Egyptians, Nubians, Iranians, Chinese, Maya, and many ancient indigenous peoples of the Americas, performed methodical observations of the night sky. Historically, astronomy has included disciplines as diverse as astrometry, celestial navigation, observational astronomy, and the making of calendars, but professional astronomy is now often considered to be synonymous with astrophysics.
Professional astronomy is split into observational and theoretical branches. Observational astronomy is focused on acquiring data from observations of astronomical objects, which 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. The two fields complement each other, with theoretical astronomy seeking to explain observational results and observations being used to confirm theoretical results.
Astronomy is one of the few sciences in which amateurs still play an active role, especially in the discovery and observation of transient events. Amateur astronomers have made and contributed to many important astronomical discoveries, such as finding new comets.
Selected article
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Triton is one of the few moons in the Solar System known to be geologically active. As a consequence, its surface is relatively young, with a complex geological history revealed in intricate and mysterious cryovolcanic and tectonic terrains. Part of its crust is dotted with geysers believed to erupt nitrogen.
The moon was discovered by British astronomer William Lassell just 17 days after Neptune itself was discovered by German astronomers Johann Gottfried Galle and Heinrich Louis d'Arrest, who were following co-ordinates given them by French astronomer and mathematician Urbain Le Verrier.
Did you know...
- ... that although color-blind, Nicholas U. Mayall was better able to detect faint galaxies than most other astronomers?
- ... that The Man in the Moone, a 1638 book by the English bishop Francis Godwin, is considered one of the first science fiction books?
- ... that the galaxy Markarian 501 produces very high energy gamma rays?
- ... that the Near-Earth object and Mars-crosser asteroid 2007 WD5 is estimated to have a 1-in-75 chance of colliding with Mars?
- ... that hydroxyl megamasers were used to make the first detection of Zeeman splitting in a galaxy other than the Milky Way?
Subcategories
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Projects
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Sunspots are temporary phenomena on the surface of the Sun (the photosphere) that appear visibly as dark spots compared to surrounding regions. They are caused by intense magnetic activity, which inhibits convection, forming areas of reduced surface temperature. Although they are at temperatures of roughly 3,000–4,500 K (4,940–7,640 °F), the contrast with the surrounding material at about 5,780 K leaves them clearly visible as dark spots, as the intensity of a heated black body (closely approximated by the photosphere) is a function of T (temperature) to the fourth power.
March anniversaries
- 7 March 2009 – The space observatory Kepler is launched by NASA to discover Earth-like planets orbiting other stars
- 13 March 1781 – William Herschel observes Uranus, which he initially believes to be a comet, eventually leading to Uranus being identified as a planet
- 14 March 1986 – The European robotic spacecraft Giotto becomes the first satellite to observe a comet up close when it flies through and photographs Halley's Comet
- 16 March 1926 – Using a mixture of gasoline and liquid oxygen, Robert H. Goddard launches the first liquid-fueled rocket
- 18 March 2011 – MESSENGER becomes the first spacecraft to orbit around the planet Mercury
Things you can do
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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
Wikijunior
Wikiversity
Hypervelocity stellar "meteors"
{{free media}}Def. a star moving faster than 65 km/s to 100 km/s relative to the average motion of the stars in the Sun's neighbourhood is called a high-velocity star.
Def. a high-velocity star moving through space with an abnormally high velocity relative to the surrounding interstellar medium is called a runaway star.
Def. a star whose elliptical orbit takes it well outside the plane of its galaxy at steep angles is called a halo star.
Astronomical events
All times UT unless otherwise specified.
| 1 March, 18:28 | Moon occults Saturn |
| 2 March, 03:59 | Moon occults Pluto |
| 4 March, 11:40 | Moon at apogee |
| 6 March, 16:04 | New moon |
| 7 March | Neptune at conjunction |
| 15 March, 01:48 | Mercury at inferior conjunction |
| 19 March, 19:55 | Moon at perigee |
| 20 March, 21:58 | Earth northward equinox |
| 21 March, 01:43 | Full moon |
| 23 March, 11:36 | Mars northward equinox |
| 29 March, 04:59 | Moon occults Saturn |
| 29 March, 11:42 | Moon occults Pluto |
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