Portal:Astronomy
Introduction
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
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?
Subcategories
- Select [►] to view subcategories
Projects
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.
February anniversaries
- 5 February 1974 – Mariner 10 becomes the first spacecraft to use a gravity assist when it flies by Venus in order to reach Mercury
- 15 February 1845 – The Leviathan of Parsonstown, the world's largest telescope from 1845 to 1917, sees first light
- 18 February 1930 – 23-year-old astronomer Clyde Tombaugh discovers Pluto by using a blink comparator on photographs he took in the previous month at Lowell Observatory
Things you can do
Here are some Open Tasks :
Astronomy featured article candidates:
Astronomy articles for which peer review has been requested: |
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.
2 February, 07:05 | Moon occults Saturn |
2 February, 20:26 | Moon occults Pluto |
4 February, 21:04 | New moon |
5 February, 07:02 | Moon occults Mercury |
5 February, 09:46 | Moon at apogee |
12 February | Comet Iwamoto at brightest |
19 February, 09:09 | Moon at perigee |
19 February, 15:54 | Full moon |
27 February, 01:24 | Mercury at greatest eastern elongation |
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: May | June | July | August | September | October | November | December
Basics
Associated Wikimedia
- Shortcuts to this page: Astronomy portal • P:ASTRO