Google has launched a service called Sky that lets you explore the heavens from within Google Earth.

You get a 3D view of all the constellations viewable from earth, and you can explore them in 3D. 100 million stars and 200 million galaxies are included.

Screenshot of Sky in Google Earth

Google’s Lior Ron writes:

You can now explore the universe from the comfort of your chair. Zoom in to distant galaxies hundreds of millions of light years away, explore the constellations, see the planets in motion, witness a supernova explosion; it’s like having a giant, virtual telescope at your command — your own personal planetarium!

To use Sky, just download the newest version of Google Earth and click on the new Sky button on the toolbar at the top of the screen.

Link via Mashable