Killer Asteroids Are Good For Life 70
Hugh Pickens writes "NASA reports that according to a study by Rebecca Martin and Mario Livio asteroid collisions may have provided a boost to the birth and evolution of complex life on earth delivering water and organic compounds to the early Earth and accelerating the rate of biological evolution with occasional impacts to disrupt a planet's environment to the point where species must try new adaptation strategies. 'Too many asteroids, and you've got an unrelenting cosmic shooting gallery, raining fiery death from above,' writes Fraser Cain. 'Too few asteroids, and complex life might not get the raw material it needs to get rolling. Life never gets that opportunity to really shake things up and evolve into more complex forms.' Martin and Livio suggest that the location of an asteroid belt relative to a Jupiter-like planet is not an accident. The asteroid belt in our solar system, located between Mars and Jupiter, is a region of millions of space rocks that sits near the 'snow line,' which marks the border of a cold region where volatile material such as water ice are far enough from the sun to remain intact. 'To have such ideal conditions you need a giant planet like Jupiter that is just outside the asteroid belt [and] that migrated a little bit, but not through the belt,' Livio explains. 'If a large planet like Jupiter migrates through the belt, it would scatter the material. If, on the other hand, a large planet did not migrate at all, that, too, is not good because the asteroid belt would be too massive. There would be so much bombardment from asteroids that life may never evolve.'"
Fermi Paradox (Score:5, Interesting)
It is amazing how little we know about the universe. Not amazing in terms of "why don't we know this stuff", but amazing in terms of "there is so much to learn that it makes what we know seem infinitesimal."
Logic and what we know already point to a universe filled with intelligent life or at least life. Yet we seem so all alone. Are we the first? Are we in a universe filled with life and cannot detect it? Has this universe been abandoned by all the more advanced life forms and we're one of the few left? Are we in a zoo?
All of these questions, and we only have speculation for answers. I'd expect to have some answers to these question in the next generation or two. We're detecting planets at an accelerating rate and are getting to discover smaller planets now that Kepler has had enough time to get enough transits for the further away planets. Our detection of radio waves ability is improving and we now have better targets to try out.
While we may not have all the answers, I would expect by 2050 to know how common life is, but part of me wonders if we haven't detected intelligent life by then if we are not truly alone in this galaxy. I shudder to think that might be true, but it is a real possibility. We live in exciting times, and I thank those that have made missions like Kepler possible.
-- MyLongNickName
Re:Nice, but speculation (Score:4, Interesting)
Of course it's speculation. How do you think you figure these things out? Time travel?
But it is potentially useful speculation. Instead of trying to find life on everything floating around random bits of fusion, look for specific parameters. Basically, one is attempting to Goldilocks the Drake Equation [wikipedia.org]. Since there appear to be lots of lots of bits of rock [discovery.com] orbiting random stars this can be a useful thing.
Hand-waving and inconsistencies (Score:4, Interesting)
"Snowline"-based conjectures actually postulate that Jupiter was formed exactly because of its location on the snowline: since this snowline has to be a sharp boundary(1), a locally-enhanced density area, radially symmetric around the Sun(2), is created and collapses into a massive planet because it rapidly accretes material(3) from its neighborhood.
I have seen a lot of hand-waving used to fill in the gaps (note: "hand-waving": (idiomatic) Discussion or argumentation involving approximation, vagueness, educated guessing, or the attempt to explain or excuse vagaries) on where and when a gas giant actually forms in a snowline, and how exactly planets 'migrate'.
(1) sharp boundaries may not be as common as you think: there is only a handful of computer models that actually take into account the three-dimensional structure of the accretion disk (proto-planetary disk, a very computationally expensive problem) and lots of physics are lost in 2D simplifications.
(3) Fairly recent observations have shown that complex organic molecules are present in Giant Molecular Cloud [wikipedia.org] structures, long preceding the formation of any star or planet. The mechanism of their creation and their distribution is mostly unknown, and an active area of research, as of course is the formation of planetary systems. Hand-waving has not produced any robust results as of yet. Computer modeling, on the other hand, looks more promising.
Re:We don't need any more of those. (Score:4, Interesting)
When have any of those things you mentioned other than nuclear war ever come close to happening outside of a sci-fi novel?
It does not only happen in sci-fi novels, it also happens in sci-fi movies. Somehow because it happens in sci-fi, lots of people think it is likely to happen in the real world as well. Why are people so easy to manipulate, that just because you make fiction about something, lots of people will actually perceive it as a real threat?
There are real threats to mankind, but I don't think mankind is a threat to life in general. We are a threat to specific species, including ourselves. But though we may cause many species to go extinct, I don't believe we could wipe out life on Earth. But is earthlife going to survive when the Sun boils away our oceans millions of years from now? If mankind goes extinct, will there be enough time for a new civilisation to develop the capability to travel through space in the Earth's lifetime?
Re:Fermi Paradox (Score:4, Interesting)
It would be pretty amazing to me if ours were the only life in the cosmos. On the otherhand, at night I just look upwards and gaze at all of the Space there is yet to Conquer.
It's an almost insurmountable task -- One that will take the peaceful cooperation on a planet-wide scale to do, but I do believe it's possible for our race survive the hostilities the Universe throws at us. I nearly shed a tear each time I hear of NASA funding getting cut while trillions are wasted on pointless war efforts. If our primary goal as a species isn't getting some of our eggs out of this one basket, then we're surely doomed...
However you look at it, we've been dealt an amazing hand. When I hear folks talk about fixing problems at home first before venturing into space I think, "What a waste it would be to fold so soon."