"Life originated on Earth" is probably the last remaining geocentrism. Literally every other geocentrism has fallen. My prediction is that this one will fall this century, probably with the discovery of simple microbial life elsewhere in the solar system followed by the genetic confirmation of common ancestry.
My favorite definition of life (courtesy of Dr. Christoph Adami and others in evolutionary informatics) is that life is a "phase of matter in which Turing-complete information processing dominates ordinary matter/energy dynamics." A phase of matter means exactly what it sounds like-- solid, liquid gas, life-- though life would be more of a rare exotic phase like a superfluid or a Bose-Einstein condensate or neutron star stuff (whatever that's called). I seem to recall him or one of his colleagues playing with terms like "computonium" or "Turium" (Turing-complete matter) for life.
Most phases of matter are found all over the place in the universe, but some places in the universe are more hospitable for some than others. Stars are great for plasma. Gas giants are full of gas. Cold icy outer planets are the ideal abodes of solids. Life, like other phases, is probably ubiquitous but Earth just happens to be a place that is peculiarly hospitable to it and a lot of it is found there. That's likely because it's at the edge of many phase boundaries (the water cycle, etc.) and it's been shown that Turing-completeness occurs in systems close to phase boundaries:
My favorite definition of life (courtesy of Dr. Christoph Adami and others in evolutionary informatics) is that life is a "phase of matter in which Turing-complete information processing dominates ordinary matter/energy dynamics." A phase of matter means exactly what it sounds like-- solid, liquid gas, life-- though life would be more of a rare exotic phase like a superfluid or a Bose-Einstein condensate or neutron star stuff (whatever that's called). I seem to recall him or one of his colleagues playing with terms like "computonium" or "Turium" (Turing-complete matter) for life.
Most phases of matter are found all over the place in the universe, but some places in the universe are more hospitable for some than others. Stars are great for plasma. Gas giants are full of gas. Cold icy outer planets are the ideal abodes of solids. Life, like other phases, is probably ubiquitous but Earth just happens to be a place that is peculiarly hospitable to it and a lot of it is found there. That's likely because it's at the edge of many phase boundaries (the water cycle, etc.) and it's been shown that Turing-completeness occurs in systems close to phase boundaries:
http://www.cc.gatech.edu/~turk/bio_sim/articles/langton_edge...