Google Sky

Google Sky is a feature for Google's Google Earth and an online sky/outer space viewer at www.google.com/sky. It shows the sky view made up of a collaboration of Hubble Telescope space photographs. It was created on August 27, 2007.

Google Earth version
The first Google Sky version to be created was on the virtual globe program called Google Earth. It features a number of layers, similar to the earth mode. It is currently facing competition from Microsoft's WorldWide Telescope.

Layers

 * Welcome to Sky: An introduction to the Sky mode.
 * Current Sky Events
 * Earth & Sky Podcasts
 * Hubblecast
 * StarDate by the University of Texas
 * VOEventNET
 * Our Solar System: Shows locations, orbits and information of the Solar System.
 * Backyard Astronomy: Shows information about constellations and other space sights visible from a backyard telescope.
 * Featured Observatories
 * Hubble Showcase
 * Spitzer Infrared Showcase
 * GALEX Ultraviolet Showcase
 * Chandra X-Ray Showcase
 * WMAP Microwave Showcase
 * IRAS Infrared Sky
 * Education Center
 * Celestron SkyScout Audio
 * Virtual Tourism
 * User's Guide to Galaxies
 * Life of a Star
 * Historical Sky Maps
 * Rumsey Star Maps
 * Hevelius Constellations
 * Sky Community: Posted KML files in the Sky forum in the Google Earth Community.

Website
Google also runs an internet version of Sky, which was created in response to the popularity of the Google Earth application.