Microsoft's answer to Google's Sky is its WorldWide Telescope, a web application that brings together imagery from ground- and space-based observatories across the world to allow people to explore the night sky through their computers.

"The WorldWide Telescope is a powerful tool for science and education that makes it possible for everyone to explore the universe," said Bill Gates, chairman of Microsoft. "By combining terabytes of incredible imagery and data with easy-to-use software for viewing and moving through all that information, the WorldWide Telescope opens the door to new ways to see and experience the wonders of space. Our hope is that it will inspire young people to explore astronomy and science, and help researchers in their quest to better understand the universe."

The application is a blend of software and Web 2.0 services created with the Microsoft Visual Experience Engine, which allows seamless panning and zooming around the night sky. WorldWide Telescope stitches together terabytes of high-resolution images of celestial bodies and displays them in a way that relates to their actual position in the sky. People can freely browse through the solar system, galaxy and beyond, or take advantage of a growing number of guided tours of the sky hosted by astronomers and educators at major universities and planetariums.

Users can choose which telescope they want to look through, including the Hubble Space Telescope, the Chandra X-Ray Observatory Center, the Spitzer Space Telescope or others. They can view the locations of planets in the night sky - in the past, present or future. They can also view the universe through different wavelengths of light to reveal hidden structures in other parts of the galaxy. Taken as a whole, the application provides a top-to-bottom view of the science of astronomy.

"Users can see the X-ray view of the sky, zoom into bright radiation clouds, and then cross-fade into the visible light view and discover the cloud remnants of a supernova explosion from a thousand years ago," said Roy Gould, a researcher at the Harvard-Smithsonian Center for Astrophysics. "I believe this new creation from Microsoft will have a profound impact on the way we view the universe."

NASA along with other organizations coordinated with Microsoft Research to provide the imagery and provide feedback on the application from a scientific point of view.

Microsoft Research is releasing WorldWide Telescope as a service free of charge to the astronomy and education communities as a tribute to Gray with the hope that it will inspire and empower kids of all ages to explore and understand the universe in an unprecedented way.