From Wikipedia, the free encyclopedia
  (Redirected from P:ASTRO)
Jump to: navigation, search
The Astronomy Portal

Astronomy portal

A man sitting on a chair mounted to a moving platform, staring through a large telescope.

Astronomy is a natural science that is the study of celestial objects (such as moons, planets, stars, nebulae, and galaxies), the physics, chemistry, and evolution of such objects, and phenomena that originate outside the atmosphere of Earth, including supernovae explosions, gamma ray bursts, and cosmic background radiation.

Astronomy is one of the oldest sciences. Prehistoric cultures have left astronomical artifacts such as the Egyptian monuments and Nubian monuments, and early civilizations such as the Babylonians, Greeks, Chinese, Indians, Iranians and Maya performed methodical observations of the night sky. However, the invention of the telescope was required before astronomy was able to develop into a modern science. Historically, astronomy has included disciplines as diverse as astrometry, celestial navigation, observational astronomy, and the making of calendars, but professional astronomy is nowadays often considered to be synonymous with astrophysics.

Show new selections

Selected article

Umbriel as seen by Voyager 2 in 1986
Umbriel /ˈʌmbriəl/ is a moon of Uranus discovered on October 24, 1851, by William Lassell. It was discovered at the same time as Ariel and named after a character in Alexander Pope's poem The Rape of the Lock. Umbriel consists mainly of ice with a substantial fraction of rock, and may be differentiated into a rocky core and an icy mantle. The surface is the darkest among Uranian moons, and appears to have been shaped primarily by impacts. However, the presence of canyons suggests early endogenic processes, and the moon may have undergone an early endogenically driven resurfacing event that obliterated its older surface.

Covered by numerous impact craters reaching 210 km (130 mi) in diameter, Umbriel is the second most heavily cratered satellite of Uranus after Oberon. The most prominent surface feature is a ring of bright material on the floor of Wunda crater. This moon, like all moons of Uranus, probably formed from an accretion disk that surrounded the planet just after its formation. The Uranian system has been studied up close only once, by the spacecraft Voyager 2 in January 1986. It took several images of Umbriel, which allowed mapping of about 40% of the moon’s surface.

Did you know


Astronomy : Archaeoastronomy - Astrophysics - Calendars - Catalogues - Celestial coordinate system - Celestial mechanics - Cosmology - Images - Large-scale structure of the cosmos - Observatories - Planetary science - Telescopes - Universe

Biographies : Astronomers - Other people - Amateur Astronomers

Astronomical objects : Lists - Galaxies - Nebulae - Planets - Stars

Spaceflight : Human spaceflight - Satellites - SETI - Spacecraft


Crab Nebula.jpg
Solar system.jpg
WikiProject Astronomy WikiProject Solar System

Ilc 9yr moll4096.png
WikiProject Cosmology WikiProject Spaceflight

Space-related Portals

Star Spaceflight Moon
Portal:Solar System
Space Solar System Mars
Portal:X-ray astronomy
X-ray astronomy Cosmology Jupiter

Selected picture

Cassiopeia A
Credit: Digitized Sky Survey, ESA/ESO/NASA FITS Liberator

Orion's Belt or The Belt of Orion is an asterism in the constellation Orion. It consists of the three bright stars: ζ Ori (Alnitak), ε Ori (Alnilam), and δ Ori

March anniversaries

Things you can do


Wikibooks logo

These books may be in various stages of development. See also the related Science and Mathematics bookshelves.


Astronomical events

All times UT unless otherwise specified.

5 March, 07:16 Moon at apogee
5 March, 18:05 Full moon
19 March, 20:32 Moon at perigee
20 March, 09:46 New moon and total solar eclipse
20 March, 23:45 Earth at northward equinox