The service taps into the latest information from leading astronomical sources including the Hubble space telescope, NASA and the UK Astronomy Technology Centre.
Users of , which has been downloaded 250m times since its launch two years ago, can access the service by clicking on a "switch to Sky" option.
Functions made available on Sky include a focus on constellations, the moon, other planets in our solar system and a tour looking at the life of a star.
Lior Ron, Google product manager, said: "We're excited to provide users with rich astronomical imagery and enhanced content that enables them to both learn about what they're seeing and tell their own stories.
"By working with some of the industry's leading experts, we've been able to transform Google Earth into a virtual telescope."
This latest innovation from Google emerged from the University of Washington's participation in the search engine giant's partnership programme with academics, called the Google Visiting Faculty Program.
Dr Carol Christian of the Space Telescope Science Institute (STScI), which was also involved in the project, said: "Never before has a roadmap of the entire sky been made so readily available. Sky in Google Earth will foster and initiate new understanding of the universe by bringing it to everyone's home computer."
This week, Google announced a new advertising format for its video-sharing service involving the overlay of advertising within video clips. The service has launched in the US and is likely to be rolled out in the UK at a later date.