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posted by martyb on Tuesday July 24 2018, @08:32PM   Printer-friendly
from the what-about-the-cheese? dept.

Earth's Moon Could Have Been Habitable 3.5 Billion Years Ago

A new paper by Ian Crawford from the University of London and myself [Dirk Schulze-Makuch], just published in the journal Astrobiology [open, DOI: 10.1089/ast.2018.1844] [DX], claims that Earth's Moon might have been habitable about one billion years after its formation, when pools of liquid water may have existed on the lunar surface. Today, of course, the Moon has no atmosphere and no liquid water. It's uninhabitable and certainly lifeless. But 3.5 billion years ago, a billion years after it formed, the lunar environment was quite different.

During this period of extreme outgassing from lunar magma, the Moon is estimated to have had an atmospheric pressure of 10 millibar, or one percent of Earth's current atmosphere. This is thicker than the current atmosphere on Mars, and would have been substantial enough for liquid water to pool on the lunar surface, perhaps for many millions of years.

Combine this with recent findings that lunar rocks are more water-rich than previously thought [DOI: 10.1038/ngeo2845] [DX], and we can hypothesize that lakes, even an ocean, could have stably existed on the Moon for a substantial amount of time. There is also evidence that the early Moon had a magnetic field [DOI: 10.1016/j.icarus.2010.08.012] [DX], which might have partially protected its surface from solar and cosmic radiation. This would have resulted in a temporarily habitable world, at a time when life on Earth had already gained a foothold.

Also at Motherboard and Astronomy Magazine.


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  • (Score: 2) by The Shire on Wednesday July 25 2018, @03:01PM (3 children)

    by The Shire (5824) on Wednesday July 25 2018, @03:01PM (#712398)

    Based on these loss rates, Needham and Kring (2017) estimated a lifetime of ∼70 million years

    70 million years. Life on earth, an infinitely better protected environment, doesn't appear to have formed until after around 700 million years. They're making ridiculous propositions that "Hey, it could have happened, you can't prove it didn't". That's not how science works. You find the evidence and you propose a theory. All these guys have is data that suggests there could have been water on the moon, nothing more. The whole "life" spiel is pure fantasy to drive clicks.

    Of course, habitability requires much more than just the presence of a significant atmosphere and liquid water. Other constraints that need to be satisfied have been elaborated elsewhere. We do not know whether there were any intrinsic organic compounds on the Moon at that time

    All they're saying is there "might" have been water which, as I pointed out, is incredibly common in the universe owing to the fact that oxygen and carbon are the second most prevalent byproducts of nuclear fusion (helium being #1). And since hydrogen is omnipresent, H2O is found literally everywhere. It's not a sign of life, it's a sign that stars are nuclear furnaces.

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  • (Score: 2) by takyon on Wednesday July 25 2018, @03:29PM (2 children)

    by takyon (881) <reversethis-{gro ... s} {ta} {noykat}> on Wednesday July 25 2018, @03:29PM (#712415) Journal

    doesn't appear to have formed until after around 700 million years.

    The start date for life on Earth has been pushed back continuously.

    Oldest Evidence of Life on Earth Found in 3.77-4.28 Billion Year Old Fossils [soylentnews.org]

    That's a range, but you can see we are getting a bit closer to the 4.5 billion mark.

    The forum article claims that the window for Moon habitability could be much longer than 70 million years, with water being maintained much longer in caves and subsurface pools, and that life might be able to form within a short amount of time with the right conditions and ingredients:

    It is instructive to put this time frame into perspective from a natural history point of view: Lazcano and Miller (1994) speculated that the time it took from the formation of suitable building blocks of life to the first cyanobacteria was no more than 10 million years. If they are correct, the transition from a nonliving to a living system might have taken place in considerably less of a time span, perhaps as little as a few thousand years. On the other hand, Orgel (1998) has argued that we simply do not understand how life, particularly its replication system, originated on primitive Earth; thus it is not possible to come up with a reliable time estimate. If abiogenesis is able to occur on short timescales, then an origin of life on the Moon cannot be excluded.

    Also note that their proposed habitability window begins at 3.5 billion years ago, not 4.5 billion years ago. The Moon could have been habitable at a point when there was already life on Earth, and life could have been carried from the Earth to the Moon by asteroid strikes. And it should be much easier for the Earth and Moon to exchange material than Earth and Mars, or Earth and Europa, etc.

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    • (Score: 2) by The Shire on Wednesday July 25 2018, @03:54PM (1 child)

      by The Shire (5824) on Wednesday July 25 2018, @03:54PM (#712432)

      You're doing the same thing they are - you're pushing the envelope of probability for the sake of click bait. It's a massive stretch to even say it's possible when then can't even prove that water was there, only that it might have. It's pointless speculation with zero evidence. Let's just stick to science instead of touchy feely wouldnt it be cool assertions.

      • (Score: 2) by takyon on Wednesday July 25 2018, @04:13PM

        by takyon (881) <reversethis-{gro ... s} {ta} {noykat}> on Wednesday July 25 2018, @04:13PM (#712445) Journal

        Or it's a useful thought experiment that will help inform further scientific study of the Moon. Since we now have countries planning to put scientists on the surface full time.

        Also it's kinda hard for me to clickbait when you're already here.

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