zoicyte t1_j1agjwq wrote
Reply to comment by me_too_999 in Mars' ancient atmosphere may not have had much oxygen after all by pecika
I think you’re a little confused. The oxidation event happened wayyyyyy before the Carboniferous; at that time atmospheric oxygen was at a historic maximum of 35%; that’s when we had dragonflies the size of eagles. Shit was crazy.
me_too_999 t1_j1ahfyp wrote
You are correct. Carboniferous was after.
Still it is believed anearobic life existed before the event.
And even though plants produce their own oxygen, they do fine in a high co2 environment, but I think they need at least a little atmospheric oxygen to grow.
zoicyte t1_j1ahnoz wrote
Anaerobic life lives now. (And life started anaerobic)
That’s nothing new. (And very old)
me_too_999 t1_j1ai6w7 wrote
And as far as I know, they could survive a low oxygen environment like present day Mars.
zoicyte t1_j1b3ias wrote
It’s not the lack of oxygen that’s the problem, it’s the surface pressure that is far too low to support liquid water.
…or the lack of an magnetic field to shield against cosmic rays and the solar wind
… or the perchlorate soil
… the freezing temperatures
Girelom t1_j1baisn wrote
How much of this problems can be avoided if life presented as bacteria who live deep underground?
zoicyte t1_j1bcsxs wrote
If you’re asking if it’s possible there could be life underground it’s definitely not impossible. Archea on earth lives in similarly extreme environments.
Basically you need at least two conditions to exist: liquid water for chemistry and an energy source. It’s possible. It won’t be very complex, you aren’t going to find a cavern full of dinosaurs, but simple cellular bacteria? It isn’t impossible to imagine conditions that would be compatible with some of the extremophiles that live on earth.
rach2bach t1_j1cmqbj wrote
All of which we find examples of extremeophiles surviving here on earth. The one that surprises .e the most are the organisms that survivehigh radiation environments, but when you think about it, they survived and thrived in early earth atmosphere. So I think it's VERY possible for organisms to exist on Mars even currently. Could be in it's crust, hell, we have organisms here that live in crystals ffs. It's definitely possible.
StrangeTangerine1525 t1_j1ex4uw wrote
The solar wind doesn't reach the surface on Mars, I believe you are thinking of UV radiation from the Sun, which goes straight through the atmosphere outside of dust storm season and would grill any microbes that aren't at least a meter below the surface.
zoicyte t1_j1f9k6c wrote
Guarantee the solar wind particles reach the ground in mars.
But yeah. UV by far is the main problem.
StrangeTangerine1525 t1_j1fupe1 wrote
You got a source for that? Mars has an ionosphere and magnetopause surrounding it, charged particles can’t get past it, and if they do, they still have the rest of the atmosphere to go through.
zoicyte t1_j1gakwm wrote
StrangeTangerine1525 t1_j1k5ceo wrote
https://lasp.colorado.edu/home/maven/the-solar-wind-and-its-interaction-with-mars-ionosphere/ and for more in depth https://www.nasa.gov/press-release/goddard/2020/mars-electric-currents. It appears the link you sent does list proton emission as a source of radiation, and that subatomic particles emitted by the Sun do reach the surface, though most are stopped by the atmosphere through processes linked above.
me_too_999 t1_j1bcnz4 wrote
A little solar wind isn't going to kill a bacteria, the perchlorate soil, and freezing temperatures may be a problem.
10yearsnoaccount t1_j1bi2du wrote
That solar UV exposure does indeed kill bacteria.... earth's surface was pretty much uninhabitable until ozone started forming
me_too_999 t1_j1bin7i wrote
How many inches does UV penetrate in Martian soil?
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