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.
(Score: 2) by The Shire on Tuesday July 24 2018, @09:35PM (9 children)
Virtually no life as we know it can survive the near vacuum conditions of 10 mbar, let alone thrive there. Even extremophiles can only barely survive in a hibernation state at such pressures and could never actually live. And this doesn't even consider the kinds of toxic gases and heat you have at that early stage. This is ridiculous on it's face.
(Score: 2) by takyon on Tuesday July 24 2018, @09:56PM (8 children)
If liquid water could pool on the surface, then microbes could have been in the water.
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(Score: 2) by suburbanitemediocrity on Tuesday July 24 2018, @11:21PM (1 child)
At 1KPa, you are barely above the triple point.
(Score: 2) by takyon on Wednesday July 25 2018, @12:02AM
*63.5% above
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(Score: 2) by The Shire on Wednesday July 25 2018, @02:19AM (5 children)
Water is one of the singular most common molecules in the universe, its literally everywhere. It's presence clearly does not by itself denote life, nor does it even mean there is a possibility of life. A thousand other factors are required just for life to survive and we don't even know what complicated chemistry is needed for it to spontaneously evolve. One thiing is certain, there are exactly ZERO theoretical models of evolving life that include a near vaccuum atmosphere. Organic chemistry just isnt going to do anything fancy under those conditions.
(Score: 2) by takyon on Wednesday July 25 2018, @02:40AM (4 children)
Take it up with the authors of the "forum article":
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(Score: 2) by The Shire on Wednesday July 25 2018, @03:01PM (3 children)
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.
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.
(Score: 2) by takyon on Wednesday July 25 2018, @03:29PM (2 children)
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:
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)
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
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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