I disagree with self styled expert and publicity hound Peiser. I'm a nanotek enthusiast but you gotta admit that there are risks with that technology. We're entering an age where given strong AI computing and nanoengineering techniques some Islamic radical or other disgruntled persons could do great damage to this world.

Anyone who has a mathematical understanding of risk knows that it's wise to diversify your portfolio. We're better off if some segment of life is dispersed to multiple biospheres even given that this is the only Earth friendly biosphere within possibly tens of thousands of lightyears.