I am a postdoc working on planetary habitability. This arxiv paper is a mesh sieve masquerading as a boat.
Complexity's rise is a messy business [1]. There's some evidence for steady progress, easy steps [2]. At the other extreme, the machinery of oxygenic photosynthesis came together once after an inexplicable billion-year delay and completely reset the biosphere. No oxygen, no complex-eukaryotes-with-twisty-genomes like you and me. Inference: that was an very improbable, difficult step, and we got lucky. Survivorship (as conscious, therefore complex creatures) biases everything we see on Earth. Nobody knows whether the origin of life was an easy or a difficult step. We don't have a geologic record of the origin of life. But the existence of even one difficult step is enough to prevent you from playing Moore's Law games.
There ARE good papers in this field that get traction out of very little data [3].
There are also reasons to think that Earth life may have originated on Mars. Joe Kirschvink (Caltech) is the big advocate of this [4]. Continued Mars exploration could test this.
Interstellar panspermia, on the other hand, is vastly improbable.
Complexity's rise is a messy business [1]. There's some evidence for steady progress, easy steps [2]. At the other extreme, the machinery of oxygenic photosynthesis came together once after an inexplicable billion-year delay and completely reset the biosphere. No oxygen, no complex-eukaryotes-with-twisty-genomes like you and me. Inference: that was an very improbable, difficult step, and we got lucky. Survivorship (as conscious, therefore complex creatures) biases everything we see on Earth. Nobody knows whether the origin of life was an easy or a difficult step. We don't have a geologic record of the origin of life. But the existence of even one difficult step is enough to prevent you from playing Moore's Law games.
There ARE good papers in this field that get traction out of very little data [3].
There are also reasons to think that Earth life may have originated on Mars. Joe Kirschvink (Caltech) is the big advocate of this [4]. Continued Mars exploration could test this.
Interstellar panspermia, on the other hand, is vastly improbable.
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[1] good (2001) review: http://wwworm.biology.uh.edu/evodevo/lecture26/carroll02.pdf
[2] opinionated summary by Simon Conway Morris: http://www.amazon.com/Lifes-Solution-Inevitable-Humans-Unive...)
[3] my favorite is Brandon Carter's argument about the number of difficult steps in our evolution: http://www.jstor.org/stable/37419
[4] Kirschvink's argument: http://www.gps.caltech.edu/users/jkirschvink/pdfs/MarsOrigin...