NASA World Wind

WorldWind is a virtual globe just like the Google Earth. It is developed by NASA and open source community.

Having support from NASA, it provides you with latest images of our Earth. Also, it gives you a virtual Moon, Mars, Venus, Jupiter along with the its moons like Ganymede, Europa and Callisto.
Another feature is the imagery of the sky and the stars, along with some information about them.

It has a list of NASA satellites that provide the images. We may select the one we like!. Global clouds, position information.

Scripting is available by which we can automate the program.

Astrobiology field guide, Landmarks catalog, etc and many other features make it a very good program. The whole archive of the image data of earth are available for free download from the NASA website to use in this program. But it may be many GBs or TB.

The image data are taken from the internet and you need a broadband connection.

The images are not taken in realtime but many days old.
One major problem is that the program is very slow and uses a lot of memory as it uses DirectX and is created in Microsoft .Net 2.0. It doesn't have th information about the roads and railways like in Google Earth.