Well, most of the people in this comment thread haven't been reading good-enough science fiction, including Paul. First, go read Accelerando by Charles Stross:

Well, most of the people in this comment thread haven't been reading good-enough science fiction, including Paul. First, go read Accelerando by Charles Stross: http://www.antipope.org/charlie/blog-static/fiction/accelerando/accelerando.html http://www.antipope.org/charlie/blog-static/fiction/accelera... And for the bits you don't understand, you can also check out the woefully incomplete but still helpful technical companion: https://en.wikibooks.org/wiki/Accelerando_Technical_Companion https://en.wikibooks.org/wiki/Accelerando_Technical_Companio... Then you'll want to read up in general on molecular nanotechnology. K. Eric Drexler has updated Engines of Creation, and its also free online: http://www.wowio.com/users/product.asp?BookId=503 http://www.wowio.com/users/product.asp?BookId=503 So if we get visited by "aliens" there's an even chance it will be some runaway Von Neumann replicator seeds shot out from a nearby solar system, bent on converting our entire solar system to computronium. Or if we're lucky, some relatively benevolent replicator seeds merely intent on cataloging all the myriad of life that has arisen around the galaxy without actually intending to destroy said life. There is just about zero chance than any recognizably biological (I prefer the term "squishy") life coming to visit us, just because sending any sizable chunk of matter across interstellar distances at any reasonable speed so so damn expensive, even for Kardashev type 2 civilizations. http://en.wikipedia.org/wiki/Kardashev_scale http://en.wikipedia.org/wiki/Kardashev_scale