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jimihendrixflyingv t1_iwvehxo wrote

Yea until we fucked that place up beyond recognition and scorched the skies. Then we came here and are now trying to find out how to get back to Mars.

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MidnightPlatinum t1_iwvgkxh wrote

This is weird to think about. Does the planet lack enough mass to keep that much water and the atmosphere such evaporation would generate?

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RhymesWith_DoorHinge t1_iwvl5vf wrote

That's only a quarter as deep as earth's oceans. That's pretty interesting if true.

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Exploding_Antelope t1_iwvlfok wrote

I feel like I’ve seen those results from a study a half dozen times over the last ten years

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Apophis_Thanatos t1_iwvm5eo wrote

Assuming some early primordial life did evolve on Mars, lets just says only algae and bacteria, would we be able to see that evidence today with just a camera on a rover?

Or would the evidence be destroyed by geological process/time?

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backtotheland76 t1_iwvrj41 wrote

I've always wondered if Mars once had a lot of water wouldn't that weigh a lot. Enough to increase it's gravity to the point of retaining all that water? Doesn't that go against current theories about how Mars lost its water. Or would all that water not really add up to much compared to the overall size of the planet.

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antoinewhitewalker t1_iwvuw6b wrote

So wait—-we’re all just gonna sit here and accept the words of a man named Martin Bizzarro as a genuine scientific theory?

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TheOutlawStarLord t1_iww18xv wrote

It was cooked off during an interstellar conflict that occurred more than 20k years ago.

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Alan_Smithee_ t1_iww1u7k wrote

Replying to Apophis_Thanatos (#569,346)

People often rail against the idea of crewed missions to Mars and other bodies, but the fact is that a geologist or exobiologist could learn more in a day than the robot rovers, great as they are, could learn in months or years.

There’s no substitute for boots on the ground.

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coren77 t1_iww3jv4 wrote

I'm really confused by this. 300meters is nowhere near 1/4 or whatever of our own oceans. Earth is 71% covered in water. Our oceans average 3700meters deep.

Further, covering the much smaller Mars 300m deep would require much less water than the same depth as earth has roughly 4x the surface area.

Am i misreading something?

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AssStuffing t1_iwwc5og wrote

That’s impossible to even know that. I’m calling bs.

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kinda_nutz t1_iwwgb32 wrote

Global warming from human produced green house gasses

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robot_tron t1_iwwhyp9 wrote

laughs in lake superior

Earth wins again you ruddy cold lump!

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LaunchTransient t1_iwwlwb3 wrote

Replying to NearABE (#569,844)

>Earth does not have enough gravity to retain helium

Nor hydrogen, which is lighter still. Your mechanism is problematic, as the Earth is both 2/3rds the distance from the sun as Mars is (and so has 2 times the UV intensity) but it also has a relatively consistent quantity of water over the last two billion years despite being glared at by those same rays.

A more likely driver of ocean loss on Mars is pressure-driven boil off. With no magnetosphere to protect it, the atmosphere gets stripped away by solar winds, causing the oceans to evaporate at an increasing rate.

The one issue I have with this hypothesis of deep oceans that have evaporated away is the apparent lack of surface evaporite deposits. Where's the salt flats?Just look at anywhere on Earth where there has been an endorheic basin - The Utah salt flats, Lake Karum in Ethiopia, Salar de Arizaro in Argentina, etc. Even under the Mediterranean sea there are layers of salt 3 kilometres thick from the era of the Messianic salt crisis. The absence of evaporite deposits just doesn't add up.

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NearABE t1_iwwpge8 wrote

Replying to LaunchTransient (#572,203)

On Earth water condenses and forms clouds. There is very little of it at the top of the atmosphere. Instead we see atomic oxygen and ozone.

>The one issue I have with this hypothesis of deep oceans that have evaporated away is the apparent lack of surface evaporite deposits. Where's the salt flats?

https://en.wikipedia.org/wiki/Vastitas_Borealis

>"Results published in the journal Science after the Phoenix mission ended reported that chloride, bicarbonate, magnesium, sodium, potassium, calcium, and possibly sulfate were detected in the samples"

Not too far off from "salt flat".

Mars has extensive dunes and dust storms. The frost reworks water soluble material. It should not look exactly the same as Earth's salt flats.

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SqueakyKnees t1_iwwqfha wrote

Replying to WontStopAtSigns (#571,885)

Just Mars's mantel is 1,560,000 meters deep. The mantel material is also more dense than water. Problem is is size is relative. 300m of water is a crazy amount to us humans, but to a planet's mass, it's not that much.

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Greatpurchase43 t1_iwwwzoq wrote

Is there any particular theory as to why they dried up or exactly what happened to them?

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LurkerInSpace t1_iwwxjcv wrote

Replying to LaunchTransient (#572,203)

To nitpick; Earth is about 70% the distance Mars is - it gets roughly twice as much sunlight rather than four times as much. Venus in turn gets about twice as much as Earth and four times as much as Mars.

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LurkerInSpace t1_iwwynta wrote

Replying to asmara1991man (#571,269)

It would need to have ~100 millibar partial pressure of oxygen to be breathable - with at least an extra 20 millibars of inert gases (or more oxygen).

Without biology oxygen doesn't stick around, so as with the early Earth the atmosphere was probably a mix of carbon dioxide and methane.

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frankthetank2023 t1_iwx2mv4 wrote

I betcha our species started on Mars but needed a new home.

So we at one point had advanced tec enough to make that journey and bring all the water with us.

But over time we lost the technology.

The Bible finally makes sense now.

There is no God.... we were the gods and mumbo-jumbo blah blah blah.

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axionic t1_iwx7awg wrote

Mars lost water when UV broke apart water molecules in the upper atmosphere. The lighter hydrogen atoms move faster and can possibly exceed escape velocity on Mars. The heavier oxygen atoms will take a suborbital path and return to the surface, which has an abundance of oxygen and very little hydrogen, although what little hydrogen there is should be enriched in deuterium, which is more likely to fall back down.

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themonkeymoo t1_iwx7ff1 wrote

Doesn't Mars have a lot more than than 300m elevation variance on its surface? How is 300m of water supposed to "cover" it?

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No_Formal_8697 t1_iwx8le1 wrote

Remember when we made a spaceship that looked like a moon and then came here and terraformed Earth after we got attacked on Mars?

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themonkeymoo t1_iwx8nsw wrote

Replying to Kelend (#573,374)

No; not right now, either. It's a lot loser to 1/12; Earth's average ocean depth is ~3700m.

That may have been shallower at some point in the very distant past (which, to be fair, also describes the last time Mars had surface water), but for as long as Earth has had continents it's probably been within rounding error of that value.

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a_toadstool t1_iwx8z5h wrote

Blows my mind that mars could’ve had intelligent life and we wouldn’t even know.

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PinwheelsAndUnicorns t1_iwxi4d0 wrote

Anyone else notice the scientist they quoted is named Martin Bizzarro?

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pmMeAllofIt t1_iwxp614 wrote

Replying to themonkeymoo (#573,713)

It's GEL- Global Equivalent Layer. Enough water to cover all of mars with 300m of water evenly. As of right now the estimates on the GEL of Mars' surface ice is 20-40m.

In comparison, the GEL of Earth's water is over 2.5km.

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Crazy-Cheesecake-945 t1_iwxp95t wrote

I speculate that we once lived on Mars, destroyed the planet, and somehow managed to escape to Earth and begin life again. Now we are destroying Earth and trying to escape this planet. I wouldn’t be surprised if once we set foot on Mars and begin digging/drilling we find evidence of human civilization there.

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PyramidBusiness t1_iwxpv7a wrote

Replying to WhiteAndNerdy85 (#571,968)

The oceans really aren't that deep if you think about it. 2 or 3 minutes down the road from your house can be a further drive than the ocean is deep.

Fun fact: The meteor that wiped out the dinosaurs was almost as big in diameter as the ocean is deep on average.

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MonsieurLeDrole t1_iwxtum7 wrote

How likely is it there were fossilized skeletons to be found? Does this mean then it's likely at at one time, both Earth and Mars had life? Any crossover with Venus?

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rocketsocks t1_iwy6r68 wrote

Replying to MidnightPlatinum (#568,814)

One thing people forget about is that water permeates through "solid" soil as well as just sitting on the surface in the form of lakes, rivers, and oceans. These sub-surface aquifers and water tables still exist today on Mars in the form of permafrost and sub-surface glaciers. The water that exists on the surface is mostly in the form of a small amount of water vapor in the atmosphere and ice in the polar caps. The rest of the water that used to exist on Mars has mostly been lost to space along with a, likely, heavier atmosphere at some point. The lighter planetary mass and lack of a magnetic field means that it's comparatively easy for molecules in the atmosphere to directly evaporate to escape velocity or to get dragged away by the solar wind. The same thing happened with much of the water on Venus, even though the gravity is much stronger there (but the planet is also much hotter).

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_-Event-Horizon-_ t1_iwyajxm wrote

Replying to WontStopAtSigns (#571,885)

For comparison the average depth of Earth's oceans is more than 3,000 meters with the deepest points going in excess of 10,000m and Earth has much bigger surface area. And Europa's oceans are theorized to be around 100Km deep.

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Crowbrah_ t1_iwyalfh wrote

Replying to merkitt (#576,283)

That's crazy talk. What we actually need to restart its core is a giant electromagnetic pulse device to fire down into Mars's fault lines. Some sort of Deep Mars Seismic Trigger Initiative or something or other.

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Bensemus t1_iwygovq wrote

Replying to MonsieurLeDrole (#575,320)

Water is key for life as we know it so having a bunch of it is good for life. There is basically zero chance Mars had anything past single cell life. It took life on Earth billions of years to go from single cell to multicellular. Mars lost its atmosphere and oceans early on. There wasn’t enough time for life to evolve like it has on Earth.

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holmgangCore t1_iwyw3kh wrote

So… this implies that we’re actually Martians!?!?

If Earth was sterilized when the moon was created, but then re-seeded with life by meteorites coming from Mars… then we might actually be Martians.

Which means when NASA’s Mars Sample Return Mission brings back the samples Perseverance is currently collecting, we might be in for a BIG surprise!

I’m hopeful at least.

Especially in light of this observation

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RunLoud6534 t1_iwz4z07 wrote

We’re gonna eventually find out humans used to be on mars until they ruined the climate so bad they moved to Earth.

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StrangeTangerine1525 t1_iwzvipv wrote

Replying to ClarkFable (#568,929)

A magnetic field isn't the primary determination for an atmosphere, Earth is the only terrestrial object with an atmosphere that has a magnetic field. Venus is roughly the same size and has an atmosphere 2 orders of magnitude larger, and lacks any kind of intrinsic magnetosphere. Planetary mass matters much more in regards to atmosphere retention, as well as temperature and atmospheric composition. Titan is another good example, were it lacks both a magnetic field and mass, but the moon is so cold that it can maintain a relatively dense atmosphere.

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StrangeTangerine1525 t1_iwzvwe4 wrote

Replying to weristjonsnow (#571,862)

There are many other methods of atmospheric escape a magnetic field can't protect against. UV rays, thermal escape processes, 'freezing' of the atmosphere into a planets crust. A magnetic field isn't the "big factor" in terms of whether not a planet has an atmosphere or not. Look at Venus and Titan, the two other places in the solar system that aren't gas giants and have atmosphere's besides Earth (and Mars). Neither of them have an intrinsic magnetic field and they still have substantial atmospheres.

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StrangeTangerine1525 t1_iwzw4m4 wrote

Replying to LaunchTransient (#572,203)

Earth has an ozone layer that causes a temperature inversion. Water can't readily reach the upper atmosphere like it can on Mars and Venus. Once Earth's temperature inversion in the middle atmosphere is gone, hydrogen and water vapor will readily escape like it does on Venus, magnetic field or not.

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StrangeTangerine1525 t1_iwzx08a wrote

Replying to danielravennest (#580,065)

Should be noted that planets with magnetic fields do still experience air loss, Earth actually loses more air to space per second currently than Mars or Venus does, mostly because our atmosphere is composed of lighter air molecules, and our magnetic field heats up the ionosphere dramatically, making it easier for molecules to escape. One other thing about Mars. It has no plate tectonics and very little volcanic outgassing, so no matter were the air is going, whether into the ground or out into space, its not getting replaced like it is on Earth or Venus.

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StrangeTangerine1525 t1_iwzyqri wrote

Replying to famished_armrest (#577,985)

In simple terms, Mars is a significantly smaller planet than Earth is, with around 10% the mass of Earth. This means that gas escapes much more readily from the planet, outgassing from volcanoes is lower because of a colder interior, asteroids do more damage to the atmosphere etc. Much of the water probably escaped during the first billion years of Mars's existence, when the Sun was far more active than it is today, and the planet was regularly bombarded by solar flares. Water high in the atmosphere would be broken apart by UV rays and its constituents would then be lost to space. Some water condensed into polar ice caps and subsurface reservoirs of ice. Even more water likely seeped into the crust and got chemically bound into rocks. It's a complex answer to a simple question. Scientists even today still don't know exactly were all the water left, but the three primary culprits are loss to space, loss to the deep crust of Mars, and then just freezing in the form of ice near the surface, which includes the water we can readily see on Mars today.

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StrangeTangerine1525 t1_iwzzc7n wrote

Replying to a_toadstool (#573,832)

Probably not. Mars doesn't have plate tectonics, and volcanic activity is low. The only forces acting on the planet that are strong enough to cause major erosion are wind loaded with dust, snow (at the poles) and occasionally flowing water, when it does occur. Any cities would still have had remnants around today that we would have seen with orbiters. If you mean intelligent but non tool using, I guess its possible. But Mars was only "not a desert" for about a billion years before becoming something pretty close to its modern self. Complex life on Earth took about 3 billion years to evolve. Any life on Mars is likely to microbial for that reason alone.

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famished_armrest t1_ix01777 wrote

Replying to StrangeTangerine1525 (#580,676)

Maybe a complex answer but you did a great job explaining it, thanks for breaking it down for me. I didn't know elements could be lost to space, that's interesting. That doesn't happen on earth right? Naturally I mean.. I thought I remembered reading in a book that the amount of matter on earth and our atmosphere never changes, basically the whole death brings life thing etc. I could be remembering wrong though.

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StrangeTangerine1525 t1_ix0awka wrote

Replying to famished_armrest (#580,897)

It does, but because Earth is larger planet, and has active recycling processes such as plate tectonics that Mars does not currently have. So while we do lose different gases to space throughout time it is replenished. Though fast forward a billion years from now, when the Sun emits roughly 10% more energy, the Earth will be hot enough that water will be able to rise from the surface directly to the upper atmosphere, and the process that dried out both Mars and Venus will begin. But that's in a billion years so we have nothing to worry about, at least on that front.

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famished_armrest t1_ix0bn2x wrote

Replying to StrangeTangerine1525 (#581,679)

Interesting. I'm sure humanity will be long gone by that point anyways. There's a really great book I read a while back called 'A Brief History of Everything' that really puts stuff like this into perspective and explains it well like you do. I remember it saying that if you looked at the history of the world as one day, humanity has been here for less than a minute, that blew my mind. Along with the fact that 99% of all creatures that have lived on this earth are already extinct. Really puts into perspective how frail and insignificant our existence really is.

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danielravennest t1_ix3c4wj wrote

Replying to StrangeTangerine1525 (#580,513)

Countering air loss, both Earth and Mars have a flux of meteor/asteroid material coming in. Mars likely gets relatively more because its orbit skims the inner edge of the Asteroid Belt. Some of the incoming objects contain volatiles.

So a full accounting of mass flow needs to consider both loss and gain processes.

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StrangeTangerine1525 t1_ix57p54 wrote

Replying to danielravennest (#589,307)

True, but because of Mar's lower gravity its less likely to keep any of those volatiles, and any that do stay are likely to freeze in to the polar caps and crust. Anyway you slice it making Mars ... less Mars is going to be quite hard.

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