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There's Life Inside Earth's Crust

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Re: There's Life Inside Earth's Crust

#31

Post by njarboe »

sheepscreek wrote: post #12
api wrote: post #7

Earlier quoted context omitted.

There are areas on Mars where we strongly believe brine is right below the surface, so there could be life underground but it may not all be that deep. Edit: found it: https://www.jpl.nasa.gov/images/pia10911-ice-on-mars-now-its... There have been cases where we believe we've seen ice form in rover tracks, hinting at water just below the surface.

This is incredibly exciting! I had no idea that we have photo evidence of ice on Mars. Thank you for sharing this! Update: It’s so hard to believe that this was captured in 2008!

Liquid water below the surface is the newer interesting part. You can see Mars ice caps with a telescope from Earth.

Re: There's Life Inside Earth's Crust

#32

Post by somenameforme »

njarboe wrote: post #31
sheepscreek wrote: post #12

Earlier quoted context omitted.

This is incredibly exciting! I had no idea that we have photo evidence of ice on Mars. Thank you for sharing this! Update: It’s so hard to believe that this was captured in 2008!

Liquid water below the surface is the newer interesting part. You can see Mars ice caps with a telescope from Earth.

I think this also derives naturally from another really interesting observation. The surface of Mars, that apparent desert, is 2%+ water by weight. [1] I say "+" because later studies have shown it to be even moister. So this is really interesting in the context of the movie/book "The Martian" because this surprise came out after the book was released.

A huge part of the plot is about him getting water which he ultimately does by extracting it from fuel, but it'd have been trivial to get it from the soil itself. If you can excuse the butchery of measurements, even just the 2% level is moist enough to extract a liter of water per cubic foot of soil! For more consistent measurements, that's 35 liters of water per cubic meter of soil!

I suspect when we finally get boots on the ground and can start doing real research and exploration, we're going to find more surprises than we could ever imagine.

[1] - https://www.space.com/22949-mars-water-discovery-curiosity-r...

Re: There's Life Inside Earth's Crust

#33

Post by sph »

ethersteeds wrote: post #29
tomalbrc wrote: post #26

Earlier quoted context omitted.

While we are talking about Kurzgesagt: https://youtube.com/watch?v=HjHMoNGqQTI

Did you not find the response from Kurzgesagt, linked below that video, to be a persuasive rebuttal? https://www.reddit.com/r/kurzgesagt/comments/10jlyyk/kurzges...

To paint a full picture and form your own opinion, here's the counter-rebuttal: https://old.reddit.com/r/thehatedone/comments/10pb1q9/my_res...

Re: There's Life Inside Earth's Crust

#34

Post by alpaca128 »

lolinder wrote: post #8
NBJack wrote: post #3

Perhaps. If it does, it probably couldn't be past a certain depth. The deepest man-made hole was about 12km, and reached roughly 180C at that depth. That's well beyond what even the most durable hyperthermophile organisms can withstand, to speak nothing of what the pressure would be like at greater depths.

Every time we assume a limitation like this we've been wrong. If tardigrades can survive floating through space, I think it's reasonable to guess that there might be life that survives at the other extreme.

While it’s true and impressive that tardigrades can survive all that, that doesn’t mean they can thrive there. They survive it by entering a stasis, but that’s about as far from living as one can get temporarily.

Re: There's Life Inside Earth's Crust

#35

Post by tim333 »

tomalbrc wrote: post #26
mohn wrote: post #9

This reminded me of a Kurzgesagt video from a few months ago on the same topic [0]. I see that the author, Karen Lloyd, was one of the experts they consulted when making that video. [0] https://www.youtube.com/watch?v=VD6xJq8NguY

While we are talking about Kurzgesagt: https://youtube.com/watch?v=HjHMoNGqQTI

That thing is "How Kurzgesagt Cooks Propaganda For Billionaires" and seems a bit of a moany biased rant about billionaires bad etc.

Re: There's Life Inside Earth's Crust

#36

Post by api »

somenameforme wrote: post #32
njarboe wrote: post #31

Earlier quoted context omitted.

Liquid water below the surface is the newer interesting part. You can see Mars ice caps with a telescope from Earth.

I think this also derives naturally from another really interesting observation. The surface of Mars, that apparent desert, is 2%+ water by weight. [1] I say "+" because later studies have shown it to be even moister. So this is really interesting in the context of the movie/book "The Martian" because this surprise came out after the book was released. A huge part of the plot is about him getting water which he ultim…

We may have to decontaminate the water, which might be full of azides or other things. On the flip side those compounds may be useful for industry or fertilizer in the long term.

Re: There's Life Inside Earth's Crust

#37

Post by tim333 »

NBJack wrote: post #3

Perhaps. If it does, it probably couldn't be past a certain depth. The deepest man-made hole was about 12km, and reached roughly 180C at that depth. That's well beyond what even the most durable hyperthermophile organisms can withstand, to speak nothing of what the pressure would be like at greater depths.

There's loads of life down there but there seems a top limit to all known life around 130C. "The current record growth temperature is 122 °C, for Methanopyrus kandleri".That allows you to go ~10km down.

Re: There's Life Inside Earth's Crust

#38

Post by tim333 »

UncleSlacky wrote: post #13

Reminds me of Thomas Gold's "Deep Hot Biosphere" theory: https://en.wikipedia.org/wiki/Thomas_Gold#%22Deep_Hot_Biosph...

I got sucked into spending quite a while reading about that stuff after seeing a link to Gold on HN. He was an interesting guy. Since he died in 2004 some of his ideas, like a lot of life in the crust seem to have proven correct. Others - that most oil and gas has a primordial origin, not from life seem mostly wrong. There are definitely primordial hydrocarbons - Titan has seas of methane. However on the inner planets a lot evaporated and the majority of our fossil fuels seem of biological origin.

There's a maybe better (very good) article on life in the crust from the NYT june 2024 here https://www.nytimes.com/2024/06/24/magazine/earth-geomicrobi... . Top comment "This article is one of the most powerful articles I have ever read in the NYT. I am so grateful that the author wrote it. It cemented my belief that that all life is deeply connected from the beginning to the present day and beyond..."

Re: There's Life Inside Earth's Crust

#39

Post by kergonath »

throwup238 wrote: post #10
lolinder wrote: post #8

Earlier quoted context omitted.

Every time we assume a limitation like this we've been wrong. If tardigrades can survive floating through space, I think it's reasonable to guess that there might be life that survives at the other extreme.

Where do you draw the line for the other "extreme"? Assuming carbon based life as we know it, 300-400C is the probably a hard limit at which point single carbon bonds begin to break down. Assuming life on earth as we know it, with ATP universally conserved across the entire evolutionary tree, the limit is really 150C. We've seen incredible survival adaptations like cryptobiosis but no organism exists that doesn't use…

> Assuming carbon based life as we know it, 300-400C is the probably a hard limit at which point single carbon bonds begin to break down.

Carbon-Carbon covalent bonds are the strongest we know. 300°C is nothing, carbon melts beyond 3000°C. Some organic molecules in our cells degrade at higher temperatures, but it depends on the availability of other species to react. Otherwise, hydrocarbon chemistry can be done beyond 300°C.

I am not saying that this kind of organisms are likely (I have no clue, it’s not my field). But from a chemical point of view there are 2 factors that could be at play:

- exotic organisms could rely on different chemistries altogether to produce energy and rely on molecules that are unstable under our standard conditions;

- and also chemistry under pressure could be very different from what we are used to on the surface.

Re: There's Life Inside Earth's Crust

#40

Post by throwup238 »

kergonath wrote: post #39
throwup238 wrote: post #10

Earlier quoted context omitted.

Where do you draw the line for the other "extreme"? Assuming carbon based life as we know it, 300-400C is the probably a hard limit at which point single carbon bonds begin to break down. Assuming life on earth as we know it, with ATP universally conserved across the entire evolutionary tree, the limit is really 150C. We've seen incredible survival adaptations like cryptobiosis but no organism exists that doesn't use…

> Assuming carbon based life as we know it, 300-400C is the probably a hard limit at which point single carbon bonds begin to break down. Carbon-Carbon covalent bonds are the strongest we know. 300°C is nothing, carbon melts beyond 3000°C. Some organic molecules in our cells degrade at higher temperatures, but it depends on the availability of other species to react. Otherwise, hydrocarbon chemistry can be done beyon…

I don’t know why you think carbon’s melting point or hydrocarbons are relevant to basic biochemistry. The “strongest” bond we know of breaks down starting at 300C (~500C for double iirc). It’s not bulk graphite or under extreme pressure underground.

You can fantasize about exotic biochemistries all you want, but what we know about carbon based life here on earth is rather specific in its limits.

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