Back to short linky goodness for a second…I just found this on bling. It starts you with a view of the Milky Way at 10 million light years from Earth, then moves you toward Earth at sucessive orders of magnitude until you are looking at the proton of a carbon atom in a tree leaf somewhere in Tallahassee. It goes pretty fast on the "Auto" setting, so try clicking on the Manual button and step through it at your own speed. A wonderful piece of imagination and science—makes me wish I'd had more time to spend at the Exploratorium the last time I was in San Francisco.