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The book Rare Earth covers this topic throughly. The conclusion they come to is that complex, multicellular life is likely extremely rare in the universe. But s

The book Rare Earth covers this topic throughly. The conclusion they come to is that complex, multicellular life is likely extremely rare in the universe. But simple, microbial life may be much more common than we think. http://www.amazon.com/Rare-Earth-Complex-Uncommon-Universe/dp/0387952896 http://www.amazon.com/Rare-Earth-Complex-Uncommon-Universe/d...

yongjik 11y ago
I didn't find the book very persuasive. The authors basically take everything that is (or might be) uncommon about the Solar System, and somehow turns them into an argument on why we are so lucky to have them. E.g., we have big Jupiter. We don't know exactly what it does, but it might have helped the Earth survive its early days. Therefore, it might be the case that the rise of complex life needed Jupiter. Yadda yadda, multiply a dozen of these things, and suddenly life on Earth looks like an incredible stroke of luck. The problem is, we don't know enough to make that verdict. What if the existence of Jupiter actually postponed the rise of life by sending big comets along our way? I enjoyed "Life Everywhere" by Darling much more, though it is probably too dated to recommend in 2016. (Astrobiology is a rapidly changing field, I suppose.)
- nickbauman 11y ago
  That's interesting remember the book explaining Jupiter had a specific influence on earth's ability to develop complex life in that its size and position made it essentially prevent a lot of comets and dangerous asteroids from hitting earth by simply getting in their way.
  - yongjik 11y ago
    I think I wrote my argument rather poorly. Let me try again: I could buy that Jupiter in our particular Solar System had the effect of clearing asteroids in the Earth's orbit. However, that doesn't automatically mean that Jupiter was essential. What if, say, Jupiter's presence in the early days of the solar system prevented these asteroids from coalescing further, resulting in the presence of the asteroids in the first place? Or what if it didn't matter in the long run anyway? Okay I just pulled that out of thin air, but what I'm saying is that there's too many unknowns to declare we needed Jupiter for life. The authors cherry-picks arguments that support their cause. Also bear in mind that this book was written in 2003, when we knew less than a dozen extrasolar planets and, IIRC, basically none looked like our Solar System (because the instruments weren't good enough to detect such systems). Even now, I don't think we know enough about planetary systems to confidently say whether Earth-like systems are common or rare.

yongjik 11y ago

I didn't find the book very persuasive. The authors basically take everything that is (or might be) uncommon about the Solar System, and somehow turns them into an argument on why we are so lucky to have them. E.g., we have big Jupiter. We don't know exactly what it does, but it might have helped the Earth survive its early days. Therefore, it might be the case that the rise of complex life needed Jupiter. Yadda yadda, multiply a dozen of these things, and suddenly life on Earth looks like an incredible stroke of luck. The problem is, we don't know enough to make that verdict. What if the existence of Jupiter actually postponed the rise of life by sending big comets along our way? I enjoyed "Life Everywhere" by Darling much more, though it is probably too dated to recommend in 2016. (Astrobiology is a rapidly changing field, I suppose.)

nickbauman 11y ago
That's interesting remember the book explaining Jupiter had a specific influence on earth's ability to develop complex life in that its size and position made it essentially prevent a lot of comets and dangerous asteroids from hitting earth by simply getting in their way.
- yongjik 11y ago
  I think I wrote my argument rather poorly. Let me try again: I could buy that Jupiter in our particular Solar System had the effect of clearing asteroids in the Earth's orbit. However, that doesn't automatically mean that Jupiter was essential. What if, say, Jupiter's presence in the early days of the solar system prevented these asteroids from coalescing further, resulting in the presence of the asteroids in the first place? Or what if it didn't matter in the long run anyway? Okay I just pulled that out of thin air, but what I'm saying is that there's too many unknowns to declare we needed Jupiter for life. The authors cherry-picks arguments that support their cause. Also bear in mind that this book was written in 2003, when we knew less than a dozen extrasolar planets and, IIRC, basically none looked like our Solar System (because the instruments weren't good enough to detect such systems). Even now, I don't think we know enough about planetary systems to confidently say whether Earth-like systems are common or rare.