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Thread: Tardigrades Were Already on the Moon

  1. #1
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    Tardigrades Were Already on the Moon

    According to this Scientific American blog, ...we know that nature has been busy cross-contaminating worlds for the past 4 billion years. And hardy little critters like tardigrades have likely already been deposited far beyond the Earth. ... (and) it is conceivable that any life in our solar system has spent the past few billion years in a merry game of natural cross-contamination; mixing it up on a regular basis.

    Why aren't we looking for lawki or its detritus? Why doesn't this assumption inform more of our missions to other bodies? Instead it seems the "holy grail" of a separate genesis event is of more concern, why?
    Where the telescope ends, the microscope begins. Which of the two has the greater view?

  2. #2
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    I think you've got this backwards. It is quite reasonable to expect that some microbes are occasionally transferred from Earth to the other objects in our Solar System, although tardigrades themselves would find it difficult to survive for long without a supporting biosphere. If any of these cross-fertilisation events result in a long-lived colony of microbes, then we would almost certainly see very distinct differences between the colony and the population on Earth - in short, evolution would occur.

    I think it is necessary to keep the microbial populations distinct on different planets, so that we could detect such evolutionary changes if they exist- which is why sending tardigrades to the Moon is foolhardy. Even though the tardigrades themselves may not survive for long, their internal gut flora (if any) might survive and skew our future results.

  3. #3
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    After a bit of puzzling, I'm guessing "lawki" is Life As We Know It, rather than a town in Poland?

    If we found Life As We Know It, could we ever tell for sure if was the result of recent lithopanspermia, or current contamination from the spacecraft / another spacecraft?
    Even if we found Life As We Sort Kinda Know It (that is, using the same molecules, but with some differences in metabolic processes and DNA) could we tell the difference between something spread by lithopanspermia long ago, and a novel organism from Earth that we just happened to encounter for the first time as a spacecraft contaminant?

    Whereas Life As We Very Definitely Don't Know It gives us a less ambiguous signal.

    Grant Hutchison

  4. #4
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    One thing we have going for us is that independent life has a 50% chance of having its DNA spiral the opposite way. That's no help if it spirals the same way, but a huge help if it doesn't.
    Last edited by Ken G; 2019-Aug-27 at 07:53 PM.

  5. #5
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    Quote Originally Posted by Ken G View Post
    One thing we have going for us is that independent life has a 50% chance of having its DNA spiral the opposite way. That's no help if it spirals the same way, but a huge help if it doesn't.
    Not to mention biospheres where DNA is a racemic mixture, or uses RNA alone, or one of the other nucleic acids. (If such exist).

  6. #6
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    Quote Originally Posted by A.DIM
    Why aren't we looking for lawki or its detritus? Why doesn't this assumption inform more of our missions to other bodies? Instead it seems the "holy grail" of a separate genesis event is of more concern, why?
    practically, we are are afraid to contaminate planets with terrestrial life :-/


  7. #7
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    Quote Originally Posted by eburacum45 View Post
    Not to mention biospheres where DNA is a racemic mixture, or uses RNA alone, or one of the other nucleic acids. (If such exist).
    Some other nucleic acids:
    TNA: https://en.wikipedia.org/wiki/Threose_nucleic_acid
    GNA: https://en.wikipedia.org/wiki/Glycol_nucleic_acid
    PNA: https://en.wikipedia.org/wiki/Peptide_nucleic_acid
    and this does not take into account other nucleic acid bases https://en.wikipedia.org/wiki/Nucleo...al_nucleobases
    SHARKS (crossed out) MONGEESE (sic) WITH FRICKIN' LASER BEAMS ATTACHED TO THEIR HEADS

  8. #8
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    I have heard of these alternatives, but I am unsure whether they would be as capable of forming persistent genetic material as DNA.

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