It brought Robert Scoble to tears... and I can see why. This is the sort of software Microsoft should be releasing. The seamless integration, very similar to what Google Earth did for looking around our little blue-green planet, makes it that much more accessible. I've tried downloading those huge images from Hubble and never had a computer with enough memory to open one. Making those high resolutions accessible opens up worlds (excuse the pun) to everyone from any walk of life... not just a handful of super computers around the world.
I can't wait to give this thing a spin, and I only wish Carl Sagan or Douglas Adams were still around to narrate tours around the universe.