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(Extreme Tech)   What Mars might have looked like billions of years ago   (extremetech.com) divider line 19
    More: Interesting, scientific reasoning, Mars Global Surveyor, Mars Reconnaissance Orbiter, Olympus Mons, gullies, Valles Marineris, surface waters, deserts  
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7025 clicks; posted to Geek » on 04 Jan 2013 at 1:49 PM (1 year ago)   |  Favorite    |   share:  Share on Twitter share via Email Share on Facebook   more»



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2013-01-04 08:56:52 PM
2 votes:

NobleHam: I'm far from an expert, so maybe someone who is could answer this question: Does Mars even have enough gravity to support an Earth-like atmosphere? Even if the gas proportions were right, I thought the gravity was too low to sustain a thick atmosphere.


It's not *really* a question of gravity. Venus has a bit less gravity than Earth, and it's got 90 times more atmosphere. Mercury has about the same gravity as Mars, yet it has none at all. If Mars had the same amount of atmospheric gases as Earth, the surface pressure would only be about 40% of sea level, but that's breathable (be like living in Nepal). Yeah, there's a certain part gravity has to play in which elements can be part of an atmosphere, but overall it's much more about the fact that Mars doesn't have a magnetic field or continuing volcanism.

At one time in the distant past, Mars did have a magnetosphere. There's some evidence that a giant impact may have disrupted its core (there's a huge basin on Mars where the rocks show no magnetic polarization, in contrast to the bedrock everywhere else), or it may be that Mars is so small, areologic activity ceased early in its development and the magnetosphere faded away.

In any case, Mars lacks protection from the solar wind, and so its atmosphere (if it ever had a thick one at all) has been stripped away over the last 3,000,000,000 years or so. If Mars' interior wasn't already solidified, volcanoes could replenish the atmosphere faster than it's being lost to solar wind. Such is the case with Venus, which has only a pitifully weak magnetosphere, but plenty of volcanism.

/Ideally, we'd just open a wormhole between Mars and Venus and let the pressures equalize.
//But if we could do that, there's a few hundred billion other planets we could colonize instead.
2013-01-04 04:02:28 PM
1 votes:

WorldCitizen: I very seriously doubt it would have had the green land and blue atmosphere billions of years ago even if it had oceans of water. Plant life first appeared on land on earth, what, a half of billion years ago after having been confined to the seas for billions of years? The atmosphere is blue because of all the oxygen life put into it.  So, oceans? Yeah, sure, maybe. Green land and blue skies? Yeah, not so much.


For a green Mars you assuming that if life got going on Mars that it's evolutionary path would be the same as it was here. All multi-cell life evolved in under the last billion years while the first sings of life happens about 3.5byo, if life on Mars didn't have that 2.5 billion year break, you could easily have a green Mars in a short period of time. Once they emerged on land it took about less then 100 millions years to green the Earth.
2013-01-04 03:57:05 PM
1 votes:
Without its magnetic field, Mars lost its atmosphere in a big way. It is entirely possible that oceans and life were in place on Mars and were eventually lost. It would happen to us here too if we lost our only protection from the Sun.
2013-01-04 03:30:22 PM
1 votes:

MrBallou: Artist's conception

[i49.tinypic.com image 649x445]


postmortemstudios.files.wordpress.com
Hey, that's pretty good!
2013-01-04 03:20:41 PM
1 votes:

anfrind: Furthermore, as I understand it it's still not clear how aerobic respiration evolved, so we don't know the odds that an oxygen revolution would happen similar to Earth's, as opposed to all of the primordial microbes being poisoned by high levels of atmospheric oxygen, or even developing resistance to atmospheric oxygen without developing aerobic respiration.


I think the Oxygen Catastrophe was slow enough in coming that something would have evolved aerobic respiration regardless. You have to remember, for a billion years most of the free oxygen generated was basically rusting the dissolved iron out of the oceans, which would have kept atmospheric levels low. And aerobic respiration represents an enormous leap in the amount of energy available to an organism, which would be a huge competitive advantage in an anaerobic world.

What I find so crazy about the Oxygen Catastrophe is that it basically saved Earth's water. Solar radiation regularly cleaves water into hydrogen and oxygen; Earth is small enough that the freed hydrogen has a chance of escaping into space. That's what happened to Venus, all of its water basically floated away as hydrogen. With enough free oxygen in the atmosphere, the cleaved hydrogen will recombine back into water before it escapes.
2013-01-04 03:19:59 PM
1 votes:

Stone Meadow: K.B.O. Winston: Smeggy Smurf: Mars is colder than Earth and it's DEAD! More proof that global warming is good for the planet. It was warmer when the dinosaurs were alive and they only were wiped out by outside forces.

Which raises the tantalizing question: is modern civilization (complete with cars and fossil fuels) a good candidate for life on Mars? If we could handle the extreme cold for a few generations, would our presence - even without pro-active terraforming - make the planet more and more habitable?

/working on a story about a Mars colony right now
//getting a kick

You REALLY need to read Robinson's Mars trilogy.


Cool!

Working through Rogue in Space now. I'll add that to the list.
2013-01-04 03:13:30 PM
1 votes:
Also if there were seas like that there would be evidence for it on the surface. Something the size of an ocean would have left behind a shoreline that would be incredibly obvious.
2013-01-04 03:12:49 PM
1 votes:

K.B.O. Winston: Smeggy Smurf: Mars is colder than Earth and it's DEAD! More proof that global warming is good for the planet. It was warmer when the dinosaurs were alive and they only were wiped out by outside forces.

Which raises the tantalizing question: is modern civilization (complete with cars and fossil fuels) a good candidate for life on Mars? If we could handle the extreme cold for a few generations, would our presence - even without pro-active terraforming - make the planet more and more habitable?

/working on a story about a Mars colony right now
//getting a kick


You REALLY need to read Robinson's Mars trilogy.
2013-01-04 03:10:51 PM
1 votes:

Smeggy Smurf: Mars is colder than Earth and it's DEAD! More proof that global warming is good for the planet. It was warmer when the dinosaurs were alive and they only were wiped out by outside forces.


Which raises the tantalizing question: is modern civilization (complete with cars and fossil fuels) a good candidate for life on Mars? If we could handle the extreme cold for a few generations, would our presence - even without pro-active terraforming - make the planet more and more habitable?

/working on a story about a Mars colony right now
//getting a kick
2013-01-04 02:57:08 PM
1 votes:

pastorkius: WorldCitizen: I very seriously doubt it would have had the green land and blue atmosphere billions of years ago even if it had oceans of water. Plant life first appeared on land on earth, what, a half of billion years ago after having been confined to the seas for billions of years? The atmosphere is blue because of all the oxygen life put into it.  So, oceans? Yeah, sure, maybe. Green land and blue skies? Yeah, not so much.

Photosynthesis started as early as 3.5 Ga on Earth. Couldn't account for all the green land though, unless the land was particularly moist and could host quasi-cyanobacteria which evolved in thin films or something.


Furthermore, as I understand it it's still not clear how aerobic respiration evolved, so we don't know the odds that an oxygen revolution would happen similar to Earth's, as opposed to all of the primordial microbes being poisoned by high levels of atmospheric oxygen, or even developing resistance to atmospheric oxygen without developing aerobic respiration.

/not a biologist; feel free to correct me if I'm wrong
2013-01-04 02:28:33 PM
1 votes:
Already been done...

4.bp.blogspot.com
2013-01-04 02:27:29 PM
1 votes:
What Mars might have looked like billions of years ago would look like if you set an arbitrary sea level and paint the remaining areas arbitrarily with an Earth vegetation and cloud color palette.

Fixed it for you, Subs!
2013-01-04 02:08:28 PM
1 votes:

WorldCitizen: I very seriously doubt it would have had the green land and blue atmosphere billions of years ago even if it had oceans of water. Plant life first appeared on land on earth, what, a half of billion years ago after having been confined to the seas for billions of years? The atmosphere is blue because of all the oxygen life put into it.  So, oceans? Yeah, sure, maybe. Green land and blue skies? Yeah, not so much.


Photosynthesis started as early as 3.5 Ga on Earth. Couldn't account for all the green land though, unless the land was particularly moist and could host quasi-cyanobacteria which evolved in thin films or something.
2013-01-04 02:07:37 PM
1 votes:
I think they meant to say "what it would look like if we just dumped water on the surface of mars and added some trees and such".
2013-01-04 01:59:24 PM
1 votes:

Smeggy Smurf: Mars is colder than Earth and it's DEAD! More proof that global warming is good for the planet. It was warmer when the dinosaurs were alive and they only were wiped out by outside forces.


And Venus is warmer than the Earth and DEAD. In fact, even more dead. Humans could actually live on Mars - we would dissolve on Venus.

My suggestion would be to just leave everything the way we found it.

/yes, I know that you are trolling
2013-01-04 01:57:30 PM
1 votes:
I stopped reading after Mars doesn't currently have water or life. May even have life on the surface. Try again.
2013-01-04 01:54:17 PM
1 votes:
graphic-engine.swarthmore.edu
2013-01-04 11:47:55 AM
1 votes:
Also pictured: what Mars might not have looked like billions of years ago.
2013-01-04 11:44:57 AM
1 votes:
I very seriously doubt it would have had the green land and blue atmosphere billions of years ago even if it had oceans of water. Plant life first appeared on land on earth, what, a half of billion years ago after having been confined to the seas for billions of years? The atmosphere is blue because of all the oxygen life put into it.  So, oceans? Yeah, sure, maybe. Green land and blue skies? Yeah, not so much.
 
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