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Space

Chicxulub Impact Might Have Spread Life-Bearing Rocks Through the Solar System 161

Posted by samzenpus
from the big-boom dept.
KentuckyFC writes "Some 65 million years ago, an asteroid the size of a small city hit the Yucatan Peninsula in what is now Mexico, devastating Earth and triggering the sequence of events that wiped out the dinosaurs. This impact ejected 70 billion kg of Earth rock into space. To carry life around the Solar System, astrobiologists say these rocks must have stayed cool, less than 100 degrees C, and must also be big, more than 3 metres in diameter to protect organisms from radiation in space. Now they have calculated that 20,000 kilograms of this Earth ejecta must have reached Europa, including at least one or two potentially life-bearing rocks. And they say similar amounts must have reached other water-rich moons such as Callisto and Titan. Their conclusion is that if we find life on the moons around Saturn and Jupiter, it could well date from the time of the dinosaurs (or indeed from other similar impacts)."
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Chicxulub Impact Might Have Spread Life-Bearing Rocks Through the Solar System

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  • Re:And Vise-Versa (Score:5, Insightful)

    by MightyMartian (840721) on Monday November 18, 2013 @04:29PM (#45457357) Journal

    A nice example of how panspermia might happen. It's a helluva leap between having life-bearing rocks blasted off of earth by a massive meteor collision, and quite another to suggest that the rest of the solar system could have been seeded.

  • Re:incorrect! (Score:5, Insightful)

    by TheCarp (96830) <[ten.tenaprac] [ta] [cjs]> on Monday November 18, 2013 @04:58PM (#45457655) Homepage

    Nuh uh. Animals don't have souls[1]

    [1] Ref 1989 - Confraternity of Christian Doctrine class - incidentally the very topic that convinced me finally that "they just made all this up", and convinced me, much to my mother's dismay, that I was done with CCD and religion.

  • by i kan reed (749298) on Monday November 18, 2013 @04:59PM (#45457663) Homepage Journal

    Well, yes and no. The genetic drift measurements we use depend on a relatively consistent rate of selection. A few generations in a hyper-extreme environment, with lots of territory and niches to gain, and lots of extinction potential might happen at a substantially faster and less predictable rate. Especially since extreme environments have been shown to affect mutation rate.

  • Re:And Vise-Versa (Score:5, Insightful)

    by Charliemopps (1157495) on Monday November 18, 2013 @05:29PM (#45457967)

    Europa has liquid water geysers, and fissures that routinely open up and then re-freeze. Think of the top layer of ice as our earths crust and the (possible) liquid ocean beneath like our liquid rock core. The surface ice shifts constantly and allows briney water to escape to the surface before it re-freezes.

    Now, what are the chances that a microbe laden rock would land in one of these crevasses? Pretty low, but keep in mind it's frozen, and could remain frozen on the surface for a very long time waiting for a crack to open beneath it. The odds are still pretty low I admit, but then keep in mind that these large collisions, microbe laden asteroids and Europa's ice flows have been going on for billions of years. Even if the odds per event are almost nil, the cumulative effect is staggering.

    When I think of space, I find it hard to believe anything is "impossible" given the vastness and near timelessness of it all. Granted there are some universal physical laws (speed of light) that make some things impossible. But anything that is simply "very very unlikely" has probably already happened.

  • Re: incorrect! (Score:4, Insightful)

    by icebike (68054) on Monday November 18, 2013 @05:30PM (#45457979)

    I'm sure the point was not missed.

    But I'm also sure the misspelling grabbed ColdWetDog's eyeballs and bitchslapped them so hard that was necessary to triple read the post just to extract any meaning, while at the same time choking back a guffaw.

  • by mmell (832646) <mike@the-mells.com> on Monday November 18, 2013 @05:31PM (#45457989) Homepage
    Yon organic matter needn't survive, reproduce and grow - it only needs to introduce the kind of complex organic molecules (amino acids, protiens, etc.) which form the foundation of evolutionary life on this planet. Hell, all the microbes in question (be there one or one million) can die on impact as long as their protiens/nucleic acids etc. remain (even partially) intact. Planetery physics will take care of the rest.

    Just don't expect anything familiar to evolve out there.

  • Re:And Vise-Versa (Score:4, Insightful)

    by hubie (108345) on Monday November 18, 2013 @05:34PM (#45458023)

    This is addressed in the paper. The paper abstract:

    Material from the surface of a planet can be ejected into space by a large impact, and could carry primitive life forms with it. We performed n-body simulations of such ejecta to determine where in the Solar System rock from Earth and Mars may end up. We find that, in addition to frequent transfer of material among the terrestrial planets, transfer of material from Earth and Mars to the moons of Jupiter and Saturn is also possible, but rare. We expect that such transfer is most likely during the Late Heavy Bombardment or during the next one or two billion years. At this time, the icy moons were warmer and likely had little or no icy shell to prevent meteorites from reaching their liquid interiors. We also note significant rates of re-impact in the first million years after ejection. This could re-seed life on a planet after partial or complete sterilization by a large impact, which would aid the survival of early life during the Late Heavy Bombardment.

  • Re:And Vise-Versa (Score:5, Insightful)

    by symbolset (646467) * on Monday November 18, 2013 @06:42PM (#45458685) Homepage Journal

    Not really. Somebody computed the likelihood of Chicxulub material making its way to the nearest stars and found it not only a certainty, but they were able to estimate the total mass per neighboring star, the time en-route, and so on. In the roughly 3.5 billion years since life arose on Earth the sun has made 17 laps around the Milky Way. The Oort cloud is fairly well polluted with life. Sometimes a star comes a little too close, and we do some border trade on the frontier. Interstellar comets pass through every year gathering up a little bit on their lonely journey. Sometimes they run into things, and leave a little litter from what they've picked up on their road trip. Consider that the Milky Way had an 8 billion year head start on us, and the conclusion is obvious.

    Space is big. Really, really mind-bogglingly big. But time is also long.

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