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The existence of liquid water on such bodies, particularly in the early solar system when such bodies were warmed by short lived radioactive decay, has strong i

The existence of liquid water on such bodies, particularly in the early solar system when such bodies were warmed by short lived radioactive decay, has strong implications for theories of the origin of life. It's possible life originated in such a body, then later was seeded onto Earth (and Mars, and Venus) when impacts dispersed life-bearing fragments to later fall as meteorites. It's also conceivable that life could have been seeded into the nascent solar system to colonize such bodies, then later spread to the planets. This is relevant because the early origin of life on Earth is taken as evidence that origin of life is a fast, high probability process. But if its origin here depended on events that require such warm moist small bodies, then it may be that it either happened early or it wouldn't happen as all, and such an inference would be invalid.

malfist 2y ago
It's possible life was seeded on earth from Mars. Mars was hit by a massive asteroid right in its peek habitability era, and it could have flung living matter to earth just at the start of it's habitability era
marcosdumay 2y ago
> early origin of life on Earth is taken as evidence that origin of life is a fast, high probability process That's a really bad take that just won't die. Life being a fast, high probability process is one between quite a handful of explanations that fit it. But anyway, adding Mars and the asteroids into the equation doesn't radically change the numbers.
- jajko 2y ago
  If anything life as we know it is a very low probability process due to many filters that we were somehow lucky enough to pass. Some of them for sure we still don't even realize yet. Luckily for dreamers universe is vast.
- lupusreal 2y ago
  Life being plentiful in the universe, and the kind of lame arguments for this assumption, entered into the secular science enthusiast dogma as a countercultural reaction to the prevailing Christian dogma of life on Earth being special. Sagan/etc's hand-wavy argument about the number of stars being a prime example. The dogma is such that people who subscribe to it will often reflexively assume that anybody challenging it is a disingenuous Christian. FWIW I am not a Christian, nor do I have any other religion, but I think there is fair reason to doubt that advanced life is common. For one, you don't have to stack too many improbabilities to easily overpower the number of stars. Secondly, evolution isn't a process that works towards the goal of creating human-like advanced life; in fact if anything it favors crabs a lot more than smart apes. Third, and most important, the rare earth hypothesis is consistent with all of our observations thus far.
  - ricksunny 2y ago
    Counter: the [Robin] Hansonian universe. ('Grabby Aliens' in his unfortunately chosen IMO nomenclature). However rare life is, and however rarer intelligent life is, it expands to fill galaxies, even allowing for lightspeed limitation.
    - pfdietz 2y ago
      In that case, they wouldn't be in our galaxy, since the Solar System and Earth weren't taken over by aliens long ago.
    - lupusreal 2y ago
      We have one example of clever techno apes in our universe, but no examples of life expanding beyond it's originating planetary system.
  - marcosdumay 2y ago
    So, can we kill the stupid knee-jerk reactionary idea? Because it's getting close to century already (no it didn't start with Carl Sagan), and we have an entire collection of alternatives nowadays.
andrewflnr 2y ago
You're really gung-ho about this idea, huh? :) https://news.ycombinator.com/item?id=40845800 https://news.ycombinator.com/item?id=40845800
- pfdietz 2y ago
  Yep! I'm old and repetitious.
pchristensen 2y ago
We may never be able to answer definitively, but another theory is that the evolution of life is a series of steps, some with highly probable pathways (lipids with hydrophobic tails forming enclosed boundaries) and some extraordinarily improbable (formation of eukaryotic cells, incorporation of mitochondria). The book The Vital Question by biochemist Nick Lane goes into this in great depth. https://nick-lane.net/books/the-vital-question-why-is-life-the-way-it-is/ https://nick-lane.net/books/the-vital-question-why-is-life-t... He estimated that simple, single celled prokaryotic organisms should be pretty common when the right conditions and probably happened multiple times independently on Earth, but eukaryotic mitochondrial cells may have only happened one single time and all complex life is descended from that one cell. I believe that was covered in https://lexfridman.com/nick-lane/ https://lexfridman.com/nick-lane/) that
o11c 2y ago
The hard part is not "warm the ice enough to melt it into liquid water" but "don't let all the water turn into gas an escape". The phase diagram is a harsh mistress at low pressures. https://commons.wikimedia.org/wiki/File:Phase_diagram_of_water.svg https://commons.wikimedia.org/wiki/File:Phase_diagram_of_wat... For reference, the surface temperature on Ceres varies from 110K to 235K, which is -163°C to -38°C in chart units, but "effectively zero pressure" (I can't find exact numbers for Ceres, but the 100×-heavier Moon is measured in nanopascals) is off the bottom of the chart.

malfist 2y ago

It's possible life was seeded on earth from Mars. Mars was hit by a massive asteroid right in its peek habitability era, and it could have flung living matter to earth just at the start of it's habitability era

marcosdumay 2y ago

> early origin of life on Earth is taken as evidence that origin of life is a fast, high probability process That's a really bad take that just won't die. Life being a fast, high probability process is one between quite a handful of explanations that fit it. But anyway, adding Mars and the asteroids into the equation doesn't radically change the numbers.

jajko 2y ago
If anything life as we know it is a very low probability process due to many filters that we were somehow lucky enough to pass. Some of them for sure we still don't even realize yet. Luckily for dreamers universe is vast.
lupusreal 2y ago
Life being plentiful in the universe, and the kind of lame arguments for this assumption, entered into the secular science enthusiast dogma as a countercultural reaction to the prevailing Christian dogma of life on Earth being special. Sagan/etc's hand-wavy argument about the number of stars being a prime example. The dogma is such that people who subscribe to it will often reflexively assume that anybody challenging it is a disingenuous Christian. FWIW I am not a Christian, nor do I have any other religion, but I think there is fair reason to doubt that advanced life is common. For one, you don't have to stack too many improbabilities to easily overpower the number of stars. Secondly, evolution isn't a process that works towards the goal of creating human-like advanced life; in fact if anything it favors crabs a lot more than smart apes. Third, and most important, the rare earth hypothesis is consistent with all of our observations thus far.
- ricksunny 2y ago
  Counter: the [Robin] Hansonian universe. ('Grabby Aliens' in his unfortunately chosen IMO nomenclature). However rare life is, and however rarer intelligent life is, it expands to fill galaxies, even allowing for lightspeed limitation.
  - pfdietz 2y ago
    In that case, they wouldn't be in our galaxy, since the Solar System and Earth weren't taken over by aliens long ago.
  - lupusreal 2y ago
    We have one example of clever techno apes in our universe, but no examples of life expanding beyond it's originating planetary system.
- marcosdumay 2y ago
  So, can we kill the stupid knee-jerk reactionary idea? Because it's getting close to century already (no it didn't start with Carl Sagan), and we have an entire collection of alternatives nowadays.

andrewflnr 2y ago

You're really gung-ho about this idea, huh? :) https://news.ycombinator.com/item?id=40845800 https://news.ycombinator.com/item?id=40845800

pfdietz 2y ago
Yep! I'm old and repetitious.

pchristensen 2y ago

We may never be able to answer definitively, but another theory is that the evolution of life is a series of steps, some with highly probable pathways (lipids with hydrophobic tails forming enclosed boundaries) and some extraordinarily improbable (formation of eukaryotic cells, incorporation of mitochondria). The book The Vital Question by biochemist Nick Lane goes into this in great depth. https://nick-lane.net/books/the-vital-question-why-is-life-the-way-it-is/ https://nick-lane.net/books/the-vital-question-why-is-life-t... He estimated that simple, single celled prokaryotic organisms should be pretty common when the right conditions and probably happened multiple times independently on Earth, but eukaryotic mitochondrial cells may have only happened one single time and all complex life is descended from that one cell. I believe that was covered in https://lexfridman.com/nick-lane/ https://lexfridman.com/nick-lane/) that

o11c 2y ago

The hard part is not "warm the ice enough to melt it into liquid water" but "don't let all the water turn into gas an escape". The phase diagram is a harsh mistress at low pressures. https://commons.wikimedia.org/wiki/File:Phase_diagram_of_water.svg https://commons.wikimedia.org/wiki/File:Phase_diagram_of_wat... For reference, the surface temperature on Ceres varies from 110K to 235K, which is -163°C to -38°C in chart units, but "effectively zero pressure" (I can't find exact numbers for Ceres, but the 100×-heavier Moon is measured in nanopascals) is off the bottom of the chart.