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I dislike complaining about titles, but I really wish articles, especially a national laboratory, would be more honest about titles. This makes it sound like th

by bmitc 2y ago

I dislike complaining about titles, but I really wish articles, especially a national laboratory, would be more honest about titles. This makes it sound like this is the new "smoking gun" that Mars was so-called Earth-like early on. However, it was my understanding that this was already known. The largest known waterfall was already previously known to be on Mars at one point, and it was already known that Mars had oceans and rivers. Again to my knowledge, I thought it was already basically understood that Mars was a little mini-Earth the first 400 million or so years of its life until its core cooled off.

gloryjulio 2y ago
Just a curious question, is Earth's core cooling off like Mars?
- bmitc 2y ago
  I sure hope not. I would assume it's a rather dynamic situation of various periods of different relative behavior. We're certainly at its mercy though. My understanding about Mars is that it is just a much smaller planet than Earth, and it's core composition was slightly different (?), and so the core couldn't keep up and just slowly stopped "slushing around" and cooled off. That's my very loose understanding of the situation without digging into references. A quick search also seems to imply that it was the collision of Earth and another planetoid (not sure of the right name), the collision that created our rather relatively large and close Moon, injected a huge amount of heat and energy in Earth, basically re-smelting it. Plus the Moon constantly tugs and pulls on the Earth, which also probably adds to the core dynamics.
  - nonethewiser 2y ago
    So many fortunate series of events that lead to the opportunity for life. Some survivorship bias I guess.
- nonameiguess 2y ago
  Yes, it is. There was a pop-sci book that came out twenty years ago, The Life and Death of Planet Earth, which contains some speculation about the consequences of this: https://en.wikipedia.org/wiki/The_Life_and_Death_of_Planet_Earth https://en.wikipedia.org/wiki/The_Life_and_Death_of_Planet_E.... They give a low-end estimate of 500-800 million years before plate tectonics stop. Net effect would be the planet becomes uninhabitable by modern day plants and animals well before the sun goes red giant and kills off everything else.
andrewflnr 2y ago
Actually, the article text is just playing it cool. Evidence of an oxidizing atmosphere is a whole other level of Earth-like than just having liquid water. Our oxygen atmosphere is created by life. So if these rocks were in fact formed by atmospheric oxygen, that's huge. I'm not sure it's a smoking gun, but it's at least a big bang and you can reasonably look for a gun nearby.

by bmitc 2y ago

gloryjulio 2y ago

Just a curious question, is Earth's core cooling off like Mars?

bmitc 2y ago
I sure hope not. I would assume it's a rather dynamic situation of various periods of different relative behavior. We're certainly at its mercy though. My understanding about Mars is that it is just a much smaller planet than Earth, and it's core composition was slightly different (?), and so the core couldn't keep up and just slowly stopped "slushing around" and cooled off. That's my very loose understanding of the situation without digging into references. A quick search also seems to imply that it was the collision of Earth and another planetoid (not sure of the right name), the collision that created our rather relatively large and close Moon, injected a huge amount of heat and energy in Earth, basically re-smelting it. Plus the Moon constantly tugs and pulls on the Earth, which also probably adds to the core dynamics.
- nonethewiser 2y ago
  So many fortunate series of events that lead to the opportunity for life. Some survivorship bias I guess.
nonameiguess 2y ago
Yes, it is. There was a pop-sci book that came out twenty years ago, The Life and Death of Planet Earth, which contains some speculation about the consequences of this: https://en.wikipedia.org/wiki/The_Life_and_Death_of_Planet_Earth https://en.wikipedia.org/wiki/The_Life_and_Death_of_Planet_E.... They give a low-end estimate of 500-800 million years before plate tectonics stop. Net effect would be the planet becomes uninhabitable by modern day plants and animals well before the sun goes red giant and kills off everything else.

andrewflnr 2y ago

Actually, the article text is just playing it cool. Evidence of an oxidizing atmosphere is a whole other level of Earth-like than just having liquid water. Our oxygen atmosphere is created by life. So if these rocks were in fact formed by atmospheric oxygen, that's huge. I'm not sure it's a smoking gun, but it's at least a big bang and you can reasonably look for a gun nearby.