Wet paleoclimate of Mars revealed by ancient lakes at Gale Crater

October 8, 2015 by Rod Pyle
A view from the Kimberley formation looking south. The strata in the foreground dip towards the base of Mount Sharp, indicating the ancient depression that existed before the larger bulk of the mountain formed. Credit: NASA/JPL-Caltech.

We have heard the Mars exploration mantra for more than a decade: follow the water. In a new paper published October 9, 2015, in the journal Science, the Mars Science Laboratory (MSL) team presents recent results of its quest to not just follow the water but to understand where it came from, and how long it lasted on the surface of Mars so long ago.

The story that has unfolded is a wet one: Mars appears to have had a more massive atmosphere billions of years ago than it does today, with an active hydrosphere capable of storing in long-lived lakes. The MSL team has concluded that this water helped to fill Gale Crater, the MSL rover Curiosity's landing site, with sediment deposited as layers that formed the foundation for the mountain found in the middle of the crater today.

Curiosity has been exploring Gale Crater, which is estimated to be between 3.8 billion and 3.6 billion years old, since August 2012. In mid-September 2014, the rover reached the foothills of Aeolis Mons, a three-mile-high layered mountain nicknamed "Mount Sharp" in honor of the late Caltech geologist Robert Sharp. Curiosity has been exploring the base of the mountain since then.

"Observations from the rover suggest that a series of long-lived streams and lakes existed at some point between 3.8 billion to 3.3 billion years ago, delivering sediment that slowly built up the lower layers of Mount Sharp," says Ashwin Vasavada (PhD '98), MSL project scientist. "However, this series of long-lived lakes is not predicted by existing models of the ancient climate of Mars, which struggle to get temperatures above freezing," he says.

This mismatch between the predictions of Mars's ancient climate that arise from models developed by paleoclimatologists and indications of the planet's watery past, as interpreted by geologists, bears similarities to a century-old scientific conundrum—in this case, about Earth's ancient past.

At the time, geologists first began to recognize that the shapes of the continents matched each other, almost like scattered puzzle pieces, explains John Grotzinger, Caltech's Fletcher Jones Professor of Geology, chair of the Division of Planetary and Geological Sciences, and lead author of the paper. "Aside from the shapes of the continents, geologists had paleontological evidence that fossil plants and animals in Africa and South America were closely related, as well as unique volcanic rocks suggestive of a common spatial origin. The problem was that the broad community of earth scientists could not come up with a physical mechanism to explain how the continents could plow their way through Earth's mantle and drift apart. It seemed impossible. The missing component was plate tectonics," he says. "In a possibly similar way, we are missing something important about Mars."

Composite of images taken at the Kimberley formation. (A) shows a view looking south. The strata in the foreground dip towards the base of Mount Sharp, indicating the ancient depression that existed before the larger bulk of the mountain formed. (B) is a view to the west of the same sandstone formations. (C) is a close-up view of the area boxed in (A), and shows the coarse grain structure of the sandstone. (D) is a close view of grains in the rocks north of the area indicated as "Rock" in (A). Credit: NASA/JPL-Caltech.

As Curiosity has trekked across Gale Crater, it has stopped to examine numerous areas of interest. All targets are imaged, and soil samples have been scooped from some; the rocks in a select few places have been drilled for samples. These samples are deposited into the rover's onboard laboratories. Using data from these instruments, as well as visual imaging from the onboard cameras and spectroscopic analyses, MSL scientists have pieced together an increasingly coherent and compelling story about the evolution of this region of Mars.

Before Curiosity landed on Mars, scientists proposed that Gale Crater had filled with layers of sediments. Some hypotheses were "dry," implying that the sediments accumulated from wind-blown dust and sand, whereas others focused on the possibility that sediment layers were deposited in ancient streams and lakes. The latest results from Curiosity indicate that these wetter scenarios were correct for the lower portions of Mount Sharp. Based on the new analysis, the filling of at least the bottom layers of the mountain occurred mostly by ancient rivers and lakes.

"During the traverse of Gale, we have noticed patterns in the geology where we saw evidence of ancient fast-moving streams with coarser gravel as well as places where streams appear to have emptied out into bodies of standing water," Vasavada says. "The prediction was that we should start seeing water-deposited, fine-grained rocks closer to Mount Sharp. Now that we've arrived, we're seeing finely laminated mudstones in abundance." These silty layers in the strata are interpreted as ancient lake deposits.

"These finely laminated mudstones are very similar to those we see on Earth," says Woody Fischer, professor of geobiology at Caltech and coauthor of the paper. "The scale of lamination—which occurs both at millimeter and centimeter scale—represents the settling of plumes of fine sediment through a standing body of water. This is exactly what we see in rocks that represent ancient lakes on Earth. "The mudstone indicates the presence of bodies of standing water in the form of lakes that remained for long periods of time, possibly repeatedly expanding and contracting during hundreds to millions of years. These lakes deposited the sediment that eventually formed the lower portion of the mountain.

"Paradoxically, where there is a mountain today there was once a basin, and it was sometimes filled with water," says Grotzinger. "Curiosity has measured about 75 meters of sedimentary fill, but based on mapping data from NASA's Mars Reconnaissance Orbiter and images from Curiosity's cameras, it appears that the water-transported sedimentary deposition could have extended at least 150-200 meters above the , and this equates to a duration of millions of years in which lakes could have been intermittently present within the Gale Crater basin" Grotzinger says. Furthermore, the total thickness of sedimentary deposits in Gale Crater that indicate interaction with water could extend higher still—up to perhaps 800 meters above the crater floor, and possibly representing tens of millions of years.

Wet paleoclimate of Mars revealed by ancient lakes at Gale Crater
An image taken at the Hidden Valley site, en-route to Mount Sharp. A variety of mudstone strata in the area indicate a lakebed deposit, with river- and stream- related deposits nearby. Decoding the history of how these sedimentary rocks were formed, and during what period of time, was a key component in the confirming of the role of water and sedimentation in the formation of the floor of Gale Crater and Mount Sharp. Credit: NASA/JPL-Caltech.

But layers deposited above that level do not require water as an agent of deposition or alteration. "Above 800 meters, Mount Sharp shows no evidence of hydrated strata, and that is the bulk of what forms Mount Sharp. We see another 4,000 meters of nothing but dry strata," Grotzinger says. He suggests that perhaps this segment of the crater's history may have been dominated by eolian, or wind-driven, deposition, as was once imagined for the lower part explored by Curiosity. This occurred after the wet period that built up the base of the mountain.

A lingering question surrounds the original source of the water that carried sediment into the crater. For flowing water to have existed on the surface, Mars must have had a thicker atmosphere and warmer climate than has been theorized for the time frame bookending the intense geological activity in Gale Crater. Evidence for this ancient, wetter climate exists in the rock record. However, current models of this paleoclimate—factoring in estimates of the early atmosphere's mass, composition, and the amount of energy it received from the sun—come up, quite literally, dry. Those models indicate that the atmosphere of Mars could not have sustained large quantities of liquid water.

Yet the rock record discovered at Gale Crater suggests a different scenario. "Whether it was snowfall or rain, you have geologic evidence for that moisture accumulating in the highlands of the Gale Crater rim," Grotzinger says. In the case of Gale Crater, at least some of the water was supplied by the highlands that form the crater rim, but groundwater discharge—a standard explanation to reconcile wet geologic observations with dry paleoclimatic predictions—is unlikely in this area. "Right on the other side of Gale's northern rim are the Northern Plains. Some have made the argument that there was a northern ocean sitting out there, and that's one way to get the moisture that you need to match what we are seeing in the rocks." Pinpointing the possible location of an ocean, however, does not help to explain how that water managed to exist as a liquid for extended periods of time on the surface.

As climatologists try to develop new atmospheric models, help should be coming from the continuing explorations by Curiosity. "There are still many kilometers of Mars history to explore," says Fischer. He thinks that some of the most exciting data yet may come in the next few years as Curiosity climbs higher on Mount Sharp. "The strata will reveal Gale's early history, its story. We know there are rocks that were deposited underwater, in the lake. What is the chemistry of these rocks? That lake represented an interface between the water and the atmosphere, and should tell us important things about the environment of the time."

"We have tended to think of Mars as being simple," adds Grotzinger. "We once thought of the earth as being simple, too. But the more you look into it, questions come up because you're beginning to fathom the real complexity of what we see on Mars. This is a good time to go back to reevaluate all our assumptions. Something is missing somewhere."

Explore further: Curiosity rover finds clues to how water helped shape Martian landscape

More information: "Deposition, exhumation, and paleoclimate of an ancient lake deposit, Gale crater, Mars," by J.P. Grotzinger et al. Science, www.sciencemag.org/lookup/doi/10.1126/science.aac7575

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Returners
1 / 5 (6) Oct 08, 2015
"In a possibly similar way, we are missing something important about Mars."


Quite a few things.

Given the time scale you are investigating, you have to take into consideration cosmic events, such as planetary drift, and not just local "martian" events.

My initial hypothesis is that Mars was once closer to the Earth, and may even have formed closer to the Sun than the Earth currently resides. At a mere fraction of Earth's mass, Mars could be gravitationally shifted/drifted around the Solar System much more easily than would be the Earth or Venus, and therefore the planetary interaction with Jupiter and Saturn would affect Mars about 9 times more than it would affect the Earth.

Now I wouldn't exactly call that a "theory", but rather a hypothesis, however it is based on the same theories which are used to try to explain the existence of "Hot Jupiter" exo-planets, by proposing Planetary drift.
Returners
1 / 5 (6) Oct 08, 2015
There seems to be a missing element on Mars, as in a missing periodic table element, but that might not be the case.

Water can react with iron to create iron oxide. Liquid water has a much lower albedo than does water-ice. What if Mars had those liquid water oceans, and this absorbs much heat, supports a stable CO2 atmosphere...

So what happened?

I would say...chemistry...chemistry happened.

The water reacted with the iron, making iron-oxide.

The hydrogen escapes into the atmosphere and is blown away by the Sun.

As lakes decrease, albedo gradually increases, forcing further cooling. Water-ice forms at the poles and higher elevations, increasing albedo further...at some point the planet got cold enough to freeze out CO2 at the poles, and at that point almost all hydrology simply died. Had there been a nitrogen rich atmosphere, this would not have happened.

Over time, the water which remains gradually got locked away in the poles and sub-surface
javjav
1.3 / 5 (6) Oct 08, 2015
The models can not explain how it happened, but the observations tell you that it was wet. Then, what are wrong are the existing models. So this finding is a game changer, now the model makers are the ones who have to go back to the drawing board, not the geologists.
wduckss
1.4 / 5 (11) Oct 08, 2015
Since when explore Mars, everything is wrong.
She ran the water, ran the atmosphere, nothing is as on Earth. However, they will prove, by force, that is the desert the ocean, that the the atmosphere "reducing" through time (Venus, Titan, Jupiter ...).
I give all the oceans on Mars for a glass of water and one breath of air!
Jeffhans1
4 / 5 (1) Oct 08, 2015
Maybe mars had its own version of the Deccan Traps releasing far more greenhouse gases than normal in its past. It seems that life during the time of the Dinosaurs provided a positive feedback keeping the CO2 levels elevated allowing more biota to live at once than otherwise would be possible. If we ever go through with Musk's plan on Nuking Mars to release extra CO2, we might find Mars life taking advantage of now favorable environment.
Returners
1 / 5 (5) Oct 08, 2015
Maybe mars had its own version of the Deccan Traps releasing far more greenhouse gases than normal in its past. It seems that life during the time of the Dinosaurs provided a positive feedback keeping the CO2 levels elevated allowing more biota to live at once than otherwise would be possible. If we ever go through with Musk's plan on Nuking Mars to release extra CO2, we might find Mars life taking advantage of now favorable environment.


How many nukes does Musk intend to use to nuke Mars to release CO2?

Doesn't he realize that the CO2 froze out of the atmosphere in the first place? This implies that CO2 alone is not enough to have a stable atmosphere on Mars, because the winter-time pole is still much colder than the sublimation point of CO2, even if all of the CO2 initially started out in the atmosphere again.

You still need Nitrogen to stabilize the atmosphere, any way you slice it.

There are not enough nuclear weapons on Earth to melt martian poles.
AGreatWhopper
1 / 5 (7) Oct 08, 2015
I have fucking had it. I'm buying a gun. With all the messianic idiots running around it's just too dangerous not to have one for self defense.
Returners
1 / 5 (6) Oct 08, 2015
That our people have been LIED TO about AGW is profanely obvious, because Mars already has more total CO2 in it's atmosphere than does the Earth, and it is not producing enough of a greenhouse effect to even keep other CO2 from freezing out of the atmosphere on the winter pole of the planet. One again, for that you actually need nitrogen.

If you nuked Mars with enough nuclear bombs to melt all the water-ice and sublimate all the CO2 ice it would not change much of anything. Within a couple years the CO2 would freeze out on both poles again, and the water would freeze where ever it is. The only difference is then the planet would be radioactive. You would, however, succeed in creating a few tropical and temperate zone lakes...which will be permanently frozen all the way through. It would then most likely take a few more years before the lakes sublimate away and the water is again deposited back in the polar ice caps.

Not a sound plan at all.
Returners
1 / 5 (5) Oct 08, 2015
The people giving me a "1' have no idea how that works.

For that matter, half the professional astrophysicists have absolutely no idea how this works.

Go ahead, "1" me people, I don't give a damn.

You'll find out soon enough.

You have absolutely no idea how that works, and most of the people who work for NASA don't even get it even though they've actually landed space craft there.

You're clueless.

It would take at least a couple hundred-trillion kilograms of Nitrogen to stabilize Mars' atmosphere.

And that's not even considering that some of the nitrogen would be absorbed by and react with the rocks...
Returners
1 / 5 (4) Oct 08, 2015
There might be another, more practical way, but to see whether it is even remotely feasible we would need a full geologic survey of Mars. Like the way we study the interior of the Earth with lots of seismometers and Earthquakes or explosives.

Solution?

Argon...hypothetically bound in rock formations.

It exists on Mars, and I think I can present an argument why a significant amount of it is probably trapped in the Martian interior, a remnant of K40 decay.

It's safe to Breath, and it's even more inert than nitrogen. So it should be "chemically free" wherever it may be.

Now Mars would have geologically cooled much faster than Earth, which means volcanism would not have been available for as long for large amounts of gases to escape the interior of the planet as happens with Earth. So the planet cools radiologically enough to be geologically dead...but there is still scads of radioactive material breaking down...for billions of years, just "cooler".
Returners
1 / 5 (4) Oct 08, 2015
Now the boiling point of Argon is well below the coldest temperatures on Mars, so it would never freeze out.

So...what you do is use seismology to attempt to find anything resembling reservoirs or acquifers beneath the surface of the planet, and you open these up and thaw them out, releasing the gases trapped inside into the atmosphere. Since Argon (among other noble gases) will not freeze back out, it will begin to provide a thermal blanket and heat transport the same way Nitrogen would. The difference is it would take a lot less energy to drill wells and release argon than it would to somehow tractor nitrogen from Triton or Titan to Mars.

Still, you would probably need more total gas release than the total mass of all the oil drilled by man since modern industrial revolution began.

the goal is hte same though: thicken the atmosphere with a permanent gas in order to permanently aid heat transport from the equator to the poles, which will then free up CO2 safely.
Solon
1 / 5 (7) Oct 08, 2015
That all the surface features found on Mars could be produced by the combined effects of a massive solar flare followed by the materials present in an equally massive CME, will never even be considered by mainstream, but given the r.f. and microwave forces present, rapid sedimentation, and even the rapid metamorphosis of predominantly silica to granite is theoretically possible.
Returners
1 / 5 (3) Oct 08, 2015
Now of course, Argon can serve the same purpose as Nitrogen as far as thermal purposes, but you'd still need nitrogen for life on Mars, and there is almost none of it in the atmosphere, and it doesn't look to be an extremely common component of the soil either.

Ah well, nobody is going to be doing anything close to seriously trying to Terraform Mars for at least a couple hundred years at this rate anyway.
Returners
1 / 5 (4) Oct 08, 2015
I think it would be hilarious if we actually did find fossils, even macroscopic fossils, on Mars. There would be no end to the controversy.

Evolutionists would all claim it supported Panspermia, and then intelligent people like myself would have to point out that there is nothing to substantiate that.

There'd be no end to paleontological job positions.

The paleontologists will have to make even more absurd, wild guesses about what the creatures ate than they would for earth, since they have absolutely no modern life forms to compare them to.

Every piece of land will be designated as a historically significant monument/reserve, and no actual colonization or space mining will happen.

I'd still be perfectly comfortable believing in creation.
Mr_Ed
1 / 5 (2) Oct 08, 2015
@Returners. I would say the your second comment is the correct root cause for the current lack of water on Mars. Add to that, that Mars has less mass than the Earth and is therefore unable to retain a thick atmosphere for more than about 10My or so (blown away by the sun), then the cause for Mars' current condition becomes obvious. However, what has not been commented on by anybody anywhere is that Mount Sharp has distinct bathtub rings to show evidence of water but no visible evidence of cliffs caused by erosion due to wave action. If water levels were sustained for even 1,000 years there would be very obvious cliffs and beaches. But none are to be seen. If instead the water was more temporary within this crater and at a time when Mars was already getting colder, then the lake would have frozen over and slowly disappeared.
Returners
1 / 5 (2) Oct 08, 2015
Mr_Ed:
in the amount of time since the water would have been abundant, the wind erosion, even with this pathetic atmosphere, could potentially erase the structures produced by earlier water erosion.

I do agree that a frozen lake in the temperate or tropical region would eventually sublimate away due to the very low air pressure if the atmosphere was disappearing about the same time. In fact it could even boil away simultaneous with the atmosphere disappearing if it was still in liquid form as the atmosphere started to disappear.

there are other possibilities. The crater may have opened fissures in the deep crust, and the liquid water may have drained from the crater into a network of impact-related faults and fissures. In which case it would most likely still be there, deep under ground in either liquid or solid form...provided the sub-surface rock chemistry didn't break the water down and incorporate the H and O in new compounds.
Returners
1 / 5 (2) Oct 08, 2015
However, I qualify my first statement above, because we can still clearly see evidence of hydrologic action on the slopes of some mountains and canyons and such, as well as what looks like alluvial fans in many locations. These have survived the wind storms for all these eons, which is essentially compacted sediment, which should have been easier for the wind to carve up and move away as compared to a canyon wall or mountain side made of exposed igneous or metamorphic rock...

Now maybe the alluvial fans are lower in altitude and protected from the wind somehow which the higher structures, in the case of mt. sharp might have gotten blasted by stronger winds...?

I don't know, it seems like a stretch in this case.

Maybe the atmosphere was thick enough to support liquid water, but not thick enough to empower strong wave action?

I calculated max martian winds only have kinetic energy of 30mph Earth winds, which means low swell....however mars has 0.37 earth gravity.
Returners
1 / 5 (2) Oct 08, 2015
And that's complicated, because lower gravity means less kinetic energy is needed to make a big wave, but it also means rock structures don't collapse as easily, so wave action doesn't eat into the wall.

Additionally, let's disregard the planetary drift idea for a moment. The solar inputs on Mars would be about the same as they are today....in order to speculate on how powerful wave action could be on a Martian lake or ocean we would need to produce at least half-decent models of it's hypothetical atmosphere to know how energy budget transfers, possible tropical cyclones, frontal boundaries...you know climate and weather.

Of course we can't do that exactly, because we don't know how thick Mar's primordial atmosphere was. It could have been just a tad thicker than what we have now all the way to being a couple times thicker than Earth's atmosphere, or anything between.

Upper limit would be found by calculating the maximum amount of mass solar wind could drive away in 3.3ga.
Returners
1 / 5 (2) Oct 08, 2015
I'm going to guess that if Mars is mostly the same as Earth at some point in the past, the Mars should have about 1/10th the total mass of EArth and therefore about 1/10th the total atmospheric mass as Earth. With a surface area of 0.284 Earths and a gravity of 0.37 Earths this leaves an rough atmospheric pressure of:

(0.1 earth mass/0.284 earth surface area)*0.37 earth gravity = 0.13 Earth surface pressure.

0.13 Earth atmospheric pressure, which is around 132mb...

The atmosphere is still thinner than Earth atmosphere, and it is lighter still due to reduced gravity.

This is not meant to be serious, because Mars would not have developed geo-chemically identical to Earth even if it started with identical composition. This is just a calculation of what the atmosphere would be if it did evolve the same...at least mass-proportionally.

I shall have to make use of several phase diagrams in order to characterize such an atmosphere.
Returners
1 / 5 (2) Oct 08, 2015
At that pressure, water still boils spontaneously at temperatures comparable to the highest Martian temperatures.

This would not exclude the existence of liquid water on the planet, but it would mean that if the atmospheric pressure was around 132mb, the weather in terms of the hydrological cycle would be extremely violent. Perhaps that explains some of the features such as the canyons and such.

There would be torrential rains...cataclysmic in our terms, at night or anytime at the poles and temperate zones, and the tropics would literally boil violently during the day time...

The crater is at the equator, indicating that under the hypothetical 132mb scenario a river depositing sediment into a lake there...by night? And it boils away during day time high temperature....leaving not much time for wave action on the cliffs to happen. Of course this is subject to the limits of solar heating in the area to keep the temperature above the boiling point for 132mb.
Returners
1 / 5 (2) Oct 08, 2015
Alternatively, the lake may have formed during aphelion and then boiled away at perihelion. I chose those terms because it's better than summer and winter in the case of a region right on the equator.

So...depending on where you are on the planet, given an atmospheric pressure of 130-140mb, Mars might actually manage to be even more of a hellish planet than it is currently.

However, everything in moderation. The poles would still be extremely cold, much colder than our own at such a pressure, so there would have to be some kind of a middle ground in which reasonable conditions existed and liquid water, both rain and ground water, should have existed if it was around that pressure level.

Do keep in mind 132 mb is about 22 times more than Mars present surface pressure.

Remember I hypothesized that number by scaling mars mass and surface gravity to Earth, assuming similar out-gasing events to scale, in the face of a lack of any tangible way to get real data.
Shootist
4 / 5 (5) Oct 08, 2015
'turners?

You're a maroon.
Returners
1 / 5 (1) Oct 09, 2015
I think several types of Earth extremophiles could probably survive in a Mars with 130 to 140mb atmospheric pressure, if the chemistry is correct. WE don't know how much atmospheric nitrogen or oxygen was at maximum, but microbes might not need that as much as Earth Plants anyway. There could be microbes that metabolize chlorine (there are some on Earth) and make use the Perchlorates, for example....

Whatever the case, it seems Bacteria or Archea might be able to survive in such a Martian scenario, but plant life or animal life as we know it would probably not survive at all IMO.

Would be interested in a computer simulation of this scenario.

135mb pressure
Nitrogen.
Oxygen (we'll assume it took some time for elemental chemistry to consume all the oxygen)
CO2. Apparently much more than on Earth
Argon: It's already there, so it must have been there back then.
Water Vapor* This would happen anyway apparently
existing noble gas elements which have survived.
Mr_Ed
1 / 5 (1) Oct 09, 2015
132 mb maybe, but the primordial atmosphere for all of the inner planets would have been greater to start with. Even the Earth's would have been thicker initially before being heated by the sun. But notice that the water in the crater appeared AFTER the crater was formed and that upper regions show no real evidence of weather (i.e. stream beds, gullies, etc). Any surface water would therefore have to come from the ground full of salts and minerals. And all surface features dampened by water in any way would get sorta caked and 'freeze-dried'. Never to move again.
Mr_Ed
1 / 5 (1) Oct 09, 2015
If one scrutinizes many of the rover and satellite images of Mars, it becomes evident that any surface water after the end of the initial warm period (and meteorite cratering) likely resulted from reheating of parts of the crust by energy from the core bubbling up through the mantle.

Take a look at the general landforms at these areas and you will see a softening of their shapes and will also appear slightly darker. Those darker areas tend to be at the head of many flash flood riverbeds.

Other than that, nothing much would have happened for the last three billion years.

Side note: As for terraforming the place, the simple answer is to just steal a moon from Saturn and drop it on Mars. Instant ocean, instant atmosphere. Should be good for a few millennia at least.
Returners
1 / 5 (1) Oct 09, 2015
Carbon Dioxide would still be unstable 130 to 140mb pressure, but result in poles melting and freezing with the seasons like on Earth, but in this case potentially driving strong winds from the warm pole to the cold pole.

So weather would be weird, because it could be driven by CO2 gas and "snow" or it could be driven by water as a liquid, vapor, or gas, or both....
Mr_Ed
not rated yet Oct 09, 2015
North-South winds are a current mars condition. Has existed for a long time. Was possibly even worse with axial precession being more unstable for Mars.
wduckss
1 / 5 (4) Oct 09, 2015
You always need to prove the universality of the claims.
Mars is smaller than Earth, but Titan is smaller than Mars. The atmosphere does not flee (not disappear) with a larger and warmer bodies, or with a smaller and colder body.
Where ice sublimates?
On Mars, the advocate the oceans, not a glass of water. Water exists (in small amounts) on some asteroids and comets, and does not flee anywhere.
The composition of the soil does not goes in favor of the existence of water nor a different atmosphere on Mars.
Instead of having looking at Mars based on the evidence, we are trying it, to force, to explain through appearance of the Earth ...
Returners
1 / 5 (1) Oct 09, 2015
wduckss:
Asteroids are farther away than Mars and are colder. there's something called the "Snow Line" which goes along with concepts like the "Habitable Zone". Snow Line is the point where water freezes and sublimation becomes very slow, however all Snow Line objects are in fact losing their water, they just lose it more slowly.

On Earth we find hydrated rock as inclusions in magmas from volcanoes formed on subduction zones. Curiosity is not near such a place and Mars mineralogy probably evolved through different chemical processes. Without plate tectonics, you wouldn't (necessarily) get water exposed to the right elements to make hydrated rock..it could happen in some places anyway, such as in the mantle, just from primordial water that was already included in the rock as the planet formed, but this rock would be difficult to access, and apparently would only surface via a super-plume or something similar.

Returners
1 / 5 (1) Oct 09, 2015
Mr_Ed:

Enceladus is almost exactly the right mass to create both a global ocean system (about 600ft (~100 meters) deep on average) and an atmosphere. "extra" water would be taken up by the basins, canyons, and deepest craters, leaving mountains and the highest planes exposed as dry land.

Calculating exactly how thick the atmosphere would be is well...not quite sure. I assume based on the properties of water that it would stabilize around 1000mb. However, the atmosphere would actually be over twice as "thick" as Earth atmosphere to achieve such a pressure, due to the lower gravity.

However, this would initially be a mostly water-vapor atmosphere plus whatever other elements Enceladus is really made of in the interior.

The collision would re-surface the entire planet anyway, and you'd have significant out-gassing from Mars from all the daughter products of radio-nuclides which were trapped in rocks all these ages, so you'd get some additional stuff too..
Mr_Ed
1 / 5 (1) Oct 09, 2015
Terraforming: See, simple as that! Just add water and stir.

And to the others who say Mars was always dry, think for a moment, the original solar nebula obviously had water in it because water is not uncommon in the universe and is not uncommon within the solar system. Therefore mars would have had it's share of water also.

So any object or planet that is now without water would require some drying out process mostly involving smaller size and/or extra solar heat (and potentially insufficient magnetic field).
Returners
1 / 5 (1) Oct 09, 2015
Well, Gale Crater itself contains several large Alluvial Fans, so the notion that Mars was always dry is immediately discarded.
Torbjorn_Larsson_OM
5 / 5 (4) Oct 09, 2015
Oookay, cranks being cranks. Sooo many erroneous claims. On the other hand it is self evident, so nothing that needs to be discussed.

But there are sensible people here as well:

@javjav, Jeffhans: Actually the cryosphere claims are not model based much, but from the orbiter observations at the time of the Vikings. However with better such observations just the other month a new hypothesis has been proposed which gives Grotzinger his warm ocean. It also provides a hypothesis for his "missing" mechanism, the concurrency with the warm ocean and the late bombardment. [ http://www.nature...rep13404 ]

Else, yes, the huge shield volcanoes could have been responsible for a "Siberian Trap" like heating event.
Returners
1 / 5 (1) Oct 09, 2015
Else, yes, the huge shield volcanoes could have been responsible for a "Siberian Trap" like heating event.

Only if the magma intruded through a massive carbon deposit, which you have nothing to substantiate this claim, and besides that it would need to be around 2 orders of magnitude bigger than the Siberian Traps...on a planet an order of magnitude smaller.

I don't buy it.

It would take a massive, massive manned effort to find evidence supporting your position even if it were true...you'd have to check every volcanic landform on the planet with multiple deep core samples to look for an unconformity in the carbon budget, in the absence of a plant fossil record. I would assume the carbon might come from abiotic calcium carbonate...
Returners
1 / 5 (1) Oct 09, 2015
Why the heck doesn't NASA every quantify the amount of Carbon (or at least the Carbon Compound) as a percent of mass of a soil sample?

I was just reading an entire NASA article on the topic and they never once stated what the actual composition of the sample was, nor even what the "organic" compounds in the rocks actually were...the statement is largely meaningless except that it isn't a pure carbon allotrope.

Like this graphic in the wiki article shows ratios of 16 different compounds (mostly metal-oxides) which make up about 45 to 50 of the soil by weight, and none of them is a carbon compound.

YOu would think that since characterizing the presence of CHONPS is Curiosity's #1 goal, they would release the results regarding those six elements! Instead P and S get mentioned in passing, and C (in the soil) really doesn't get directly mentioned at all, at least not quantified in any meaningful way.

Is mars soil 0.5% carbon? 0.1%? 1%? 10%?

Who knows...they say nothing.
Returners
1 / 5 (2) Oct 09, 2015
They don't mention nitrogen compounds in the soil. Really?

There is some nitrogen in the atmosphere, so even if the planet is dead as a doorknob there ought to be some nitrogen compounds included in the soils and rocks....

Press release? Nothing.

Is the rover not properly equipped to detect these compounds? Or what?

I think landing Curiosity in Gale Crater was a mistake, because the inferno created by the impact would have incinerated any carbon-based compounds on the site....which may well explain why they don't find anything with much carbon in it by using Curiosity, even thought that's exactly what the damn thing is supposed to be looking for.

They should go check that alluvial fan and drill into it. The soil layer there is much younger than the crater itself, and may contain sedimentary carbon originating from up on the plains above.

What a disaster of a mission planning effort that has been.
Returners
1 / 5 (1) Oct 09, 2015
Backing out the mass of the other elements in the compounds, I determined that SOME rocks on Mars contain between less than 1% carbon by mass to as much as about 5% carbon by mass, but it is in iron or magnesium carbonate compound form.

https://en.wikipe..._on_Mars

This article appears to be about 7 years old, but the relevant information was posted recently.

So overall, when they characterized the soil on Mars as being like what you would find in your back yard, I think that was too much of an exaggeration.
wduckss
not rated yet Oct 10, 2015
Returners;
If something does not give long-term results, it must leave.
The bodies of growth: gas, dust, smaller body, body without hot core (all the cold). The critical size, weight (or with the effects of gravity ..) compressive forces heated center of the body ... Graduating ~ 10% of the mass of the sun bodies lose the crust becoming classical stars (with the effect of the gravitational effect of a lot less - hot Jupiter). Mars belongs in the lower body without hot core, and is created, long-term replenished exclusively, space materials as evidenced by craters. Without active geological processes (which are directly linked to the molten interior of the body) no significant atmosphere, nor the essential amount of water ...
Returners
1 / 5 (1) Oct 10, 2015
I thought I made a post pointing out that the color palette in the photo at the top of this page is wrong.

I don't know if that's intentional or not, but the sky is not supposed to be blue. Maybe they did that intentionally to add contrast, but it's an unfortunate screw-up in processing in my opinion.

It has happened before with images from another mission.
rondy
4 / 5 (1) Oct 10, 2015
If there was water in lake Gale for so long, the temperature was higher and the atmosphere was thicker the obvious question is:
Does the absence of fossils, or at least some organic remnants of ancient microbial life, points that life most likely never existed there, despite the presence of water??
Mike_Massen
2.6 / 5 (5) Oct 11, 2015
FFS @ Returners & your rant re AGW

Re Mars
Please find out why day time temps can reach 30deg C & that poles have far less insolation, doh, same issue as Earth re angle of incidence, details re Mars climate:-
https://en.wikipe..._of_Mars

Then get a grip of the proven, settled & irrefutable Physics of:-
https://en.wikipe...transfer

Known well by Physicists for > 100 yrs !!!

Especially re CO2 here:-
https://en.wikipe..._forcing

Also do some research re magnetic field re solar wind's effect of stripping atmosphere, Mars magnetic field is far weaker than Earths, whilst at it check out Venus re greenhouse gases & climate

ie Learn Physics and learn to research before making an utter fool of yourself

shakes head

OR Returners find one single piece of evidence refuting radiative transfer & this:-
http://www.chem.a.../sim/gh/

Just ONE Returners - nobel prize ?

Better Learn Physics
eachus
not rated yet Oct 11, 2015
"In a possibly similar way, we are missing something important about Mars."


Given the time scale you are investigating, you have to take into consideration cosmic events, such as planetary drift, and not just local "martian" events.


I agree. Right now settled science about the Earth/Moon system is that Earth was hit by a Mars sized planetoid and the orbital debris got swept up to form the Moon. Current thinking is that the object became part of Earth. But since we don't know the mass of the Earth before the impact, it could be that Mars was that object and the blow was a glancing one. If so, Mars could have been left in an eccentric orbit, and planetary dynamics with Jupiter could smooth it out, pulling Mars into its current (still eccentric) orbit.

Far fetched? The impact that formed the Moon is very far fetched in any case, but seems to be the only explanation that makes sense.

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