"A program that shows marvellous images of the Universe for you to see from a digital telescope."
In the fight to offer users great and useful programs for free (maybe so as not to lose sight of their rivals at Google), Microsoft have created WorldWide Telescope, which many have now called Google Sky (and it´s also known as Google Herat) from Bill Gates.
In effect, this fantastic program reminds you of Google Sky and its aim is to offer astronomical studies from a web setting, and has been created with the Visual Experience Engine, which converts your PC into a virtual telescope to contemplate the whole world (hence the name).
The quality is such that you can see amazing images of the sky, day and night, letting you apply a wide range of effects like vision x, zoom, crossfade, etc. Imagine an image of a supernova that exploded millions of years ago!