This weeks .Net Rocks features Chris Maxwell and Randy Kim from NASA who are responsible for the amazing NASA Worldwind. If you want to skip right to the NASA stuff it starts around 11:50 in the stream.

Its really interesting that even though WorldWind loads and unloads huge amounts of data, they don't have any garbage collection issues and they didn't have any need to call the .collect() method themselves.

They also announced that the latest version of worldwind (1.3) is available for download - check out the site.