From the University of Michigan
How Mars’ atmosphere got so thin: New insights from Curiosity
ANN ARBOR—New findings from NASA’s Curiosity rover provide clues to how Mars lost its original atmosphere, which scientists believe was much thicker than the one left today.
“The beauty of these measurements lies in the fact that these are the first really high-precision measurements of the composition of Mars’ atmosphere,” said Sushil Atreya, professor of atmospheric, oceanic and space sciences at the University of Michigan.
Atreya is co-author of two related papers published in the July 19 issue of Science, and co-investigator on Curiosity’s Sample Analysis at Mars (SAM) suite of instruments, considered the rover’s cornerstone lab.
SAM measured the abundances of different gases and isotopes in samples of Martian air, according to NASA. Isotopes are variations of the same chemical element that contain different numbers of neutrons, such as the most common carbon isotope, carbon-12, and a heavier stable isotope, carbon-13, which contains an additional neutron.
SAM analyzed the ratios of heavier to lighter isotopes of carbon and oxygen in the carbon dioxide that makes up most of Mars’ atmosphere today. Measurements showed that heavy isotopes of carbon and oxygen were more abundant in today’s thin atmosphere compared with the proportions in the raw material that formed the planet (which scientists can deduce from proportions in the sun and other parts of the solar system.) This provides not only supportive evidence for the loss of much of Mars’ original atmosphere, but also gives clues to how the loss occurred. It suggests that the planet’s atmosphere escaped from the top, rather than due to the lower atmosphere interacting with the ground, NASA’s web story states.
“The isotope data are unambiguous and robust, having been independently confirmed by the quadrupole mass spectrometer and the tunable laser spectrometer, two of the SAM suite instruments,” Atreya said. “These data are clear evidence of a substantially more massive atmosphere, hence a warmer, wetter Mars in the past than the cold, arid planet we find today.”
Curiosity landed inside Mars’ Gale Crater on Aug. 6, 2012, Universal Time.
For the full NASA story, see: http://www.nasa.gov/mission_pages/msl/news/msl20130718.html
duh? loss through interaction with the ground? whoever suggested that?
even Earth is losing atmo from the top, right now.
Is it our fault?
The telegraph also covered this topic with the article “Mars’ atmosphere destroyed by ‘catastrophic’ event four billion years ago” at: http://www.telegraph.co.uk/science/10189828/Mars-atmosphere-destroyed-by-catastrophic-event-four-billion-years-ago.html#comment-968396281
I left a “sarcastic” comment that is so patently idiotic that I’m thinking it won’t be taken seriously, but if it is taken seriously it’s meant to inspire a strong skeptical reaction. “Recommend” it to bring it to the top, This is the comment:
This is confirmation of the long established idea that small planets lose their atmosphere through
what you could call “fractioned destillation” by the warmth of the Sun.
It happens on Earth as well: the Earth is constantly losing Hydrogen to space, which is made by photo-dissociation by far UV radiation of water at high altitude where the light Hydrogen moves upwards and “boils” off and the much heavier Oxigen stays behind. (Do this 4.5 billion years and you are left with a sizable fraction of Oxigen; forget about those cyano bacteria that biologist think are responsible).
Missing magnetic field leads to missing atmosphere.
This is circumstantial evidence, but because it comes from an authoritative source, you are ready to believe it. I keep finding deference to authority from you on certain topics that aren’t your expertise. Why is this? Aren’t you immune to it yet?
Aren’t there other possibilities that aren’t ruled out?
Yes it is. It’s your fault Mark.
I hope you are suitably contrite. 😉
JDN says:
July 19, 2013 at 2:06 am
This is circumstantial evidence, but because it comes from an authoritative source, you are ready to believe it. I keep finding deference to authority from you on certain topics that aren’t your expertise. Why is this? Aren’t you immune to it yet?
Aren’t there other possibilities that aren’t ruled out?
I see no ‘deference’. This was a straight report of the NASA findings from the referenced NASA release. If you can hypothesize other possibilities that would provide the same atmospheric signature then you just wasted on opportunity to do so. I am sure other commenters will provide their own ideas – some quite forcefully; that is how this board works.
@Eric Simpson:
That comment is too much like the typical warmunist comments seen on any weather disaster (you know – too much rain, too much wind, not enough rain, not enough wind, too hot, too cold, etc) story in the local paper. No one will note it as sarcasm unless you have a history on the site of fighting that meme, and you may get a bunch of the usual chorus piling on praising it as the most insightful comment ever.
It is a sad comment on our education systems!.
Given the evidence of water erosion from rover pictures then a thicker atmosphere to support this water is a good clue. Isotope ratios will give another clue, based on the isotope ratios in our atmosphere, assuming that each planet shared the same ratios. gravity difference, rotation and orbital difference could make this assumption wrong. Atmospheric loss from the top could be due to the solar wind and the poor magnetic protection of Mars whereas our magnetic field gives a lot of protection from this.
I don’t see much difference with other nasa PR self-aggrandizing press releases. Scientists found that it’s more likely that Mars, as suspectedfrom times immemorable, has lost its atmosphere from the top, like all atmosphere-able planetary bodies are losing as we speak.
The news content appear to be zero or slightly slightly a positive number.
New insights? Yes. Solved? No way. Just one more phantasy coming from people with great instruments.
A more plausible explanation, by far, is that this is just the kind of atmosphere that any rock of Mars’s size will have.
Is it scientific reporting? Are they not supposed to report isotopic ratios, error bars included? Why to keep numbers resulting from research done on taxpayers’ money behind a paywall?
What does “heavy isotopes of carbon and oxygen are both enriched” actually mean?
Eric Simpson says:
July 19, 2013 at 1:29 am
That’s funny.
I gave up engaging with anyone on discus as I was going through email addresses faster than I was prepared to create them. Mostly down to taking no shit from Guardianista imbeciles but still losing the ‘right’ to free speech if someone disagrees with what is presented to them.
I almost always attempted to stay polite because it is easy to degenerate into the mouth of foul when your responder is faceless, in another country or on another planet.
It’s a press release, not a professional paper. Presumably the results will be written up and published, I hope not behind a paywall.
What’s interesting to me is what this might, or might not, say about the possibilities for terraforming Mars to make it habitable for humans. We’ll want to make the atmosphere thicker, by a large factor, with lots of oxygen, and make the surface a lot wetter. Steering a lot of icy comets into the planet might be a start. Then we bring in the plants. . .
/Mr Lynn
N.A.S.A. .. >=< never a straight ANSWER.
Here,s one:
For centuries civilizations from around the globe practised ritual killing, some less barbaric so. The time period is 10,000 to 12,000 BC. Paintings depict two celestial bodies in battle. There size to be two thirds of our moon. Further speculation from historians, speculates that the bodies were in fact the new arrival of Venus setting into a circumference orbit. Venus appeared to suck into her tail the whole atmosphere of Mars.
Space weather i guess.
PS look up.
I remember reading about Martian atmosphere evaporating into space since 1970s. OK, they found some confirmation of this old hypothesis. But why should it exclude any other factors?
Surely, Olympus Mons has something to do with the loss of Martian atmosphere. This gigantic bump on the surface could not have appeared without some catastrophic collision that stripped part of the Martian atmosphere. Also, Olympus Mons sticks out into the airless space, thus providing an additional conduit for constant convectional loss of atmosphere.
More BS from “scientists.”
It is totally clear that the original inhabitants of Mars destroyed their atmosphere due to their destructive mining, heavy industry, driving SUVs, coal fired power plants , deforestation, killing off the spotted owl by allowing unprecedented expansion of the barn owl, tossing plastic crap into their oceans, oil drilling, fracking, breathing, eating and merely existing.
Thank god some of those Martians were able to escape to the planet earth ( generally known as Bolsheviks) and established a peaceful , environmentally sustainable nation called the USSR, which achieved UNPRECEDENTED happiness and health until destroyed by the environmentally criminal USA in 1990.
mark fraser says:
July 19, 2013 at 1:15 am
Is it our fault?
—
Let’s blame it on Bush.
And the power plant used for this rover (Because the previous solar powered rover is “unreliable” because of dust landing on the solar panels)? Nuclear!
“These data are clear evidence of a substantially more massive atmosphere, hence a warmer, wetter Mars in the past than the cold, arid planet we find today.”
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Strange that this simple fact, that a more massive atmosphere is a warmer atmosphere, is not taken into account to explain why Venus is so hot, or to explain the faint sun paradox. Instead CO2 is used to explain Earth and Venus, but this is conveniently overlooked when talking about Mars because it also has a high CO2 atmosphere, yet Mars is cold.
To large degree, the temperature of Earth, Venus and Mars varies directly as the atmospheric pressure and the inverse square of the distance from the sun, regardless of atmospheric composition.
Of the three, Venus has the densest atmosphere, yet has no magnetic field to protect the atmosphere from the solar wind. Something overlooked in the explanation of how planets lose their atmosphere.
Venus has thick clouds which largely prevent solar radiation from heating the surface. This is confirmed in the fact that daytime and nighttime temperatures are largely the same on Venus. Without solar radiation warming the surface there would be little outgoing LWR to be returned by CO2 back radiation to the surface, according to GHG theory on earth. Yet clearly this explanation does not work when applied to Venus.
Why then does climate science suggest that cloud albedo reflects solar radiation to space on earth, while the evidence is very clear that this does not happen on Venus with its much denser cloud cover? The clouds on Venus clearly cannot reflect solar radiation to space. Otherwise, what heats the surface on Venus to temperatures higher than Mercury?
Undoubtedly, future explorations will find out that the reason that the atmosphere got so thin is that the early martians constructed massive wind turbines and blew it out into outer space. 😉
These scientists apparently believe that static conditions have lasted for billions of years by their statement “which scientists can deduce from proportions in the sun and other parts of the solar system.”
ferd berple says:
July 19, 2013 at 7:00 am
“The clouds on Venus clearly cannot reflect solar radiation to space. ”
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At any frequency? Then the bright morning star would be invisible.
Ed Zuiderwijk says:
July 19, 2013 at 1:31 am
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You can’t separate light gases from oxygen that isn’t there to begin with. The geochemists agree: banded iron, etc.
Alexander Feht says:
July 19, 2013 at 6:02 am
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According to my infallible sources (Wikipedia), Olympus Mons is a volcano, formed over millions of years, as shown by increasing (meteor) crater counts from peak to perimeter. Sounds like good evidence. –AGF
Looking for a single answer to this atmospheric riddle will lead to not finding the rest of the answers. The same thing happens with Earth’s climate; It must be not only the oceanic circulations, the Sun, continental drifts, or more CO2 each dominating the scene.
I see each and all components alternating chaotically to dominate for a while, then fade away.
The thin Martian atmosphere contains about 15.5 times more CO2 (.0062 bar) than does Earth’s (.0004 bar of dry air) 169 times thicker (101.3 kilopascals vs. 600 pascals surface pressure) & 5600 times more massive (1.4 x 10^21 kg vs. ~2.5 x 10^16 kg) atmosphere. The relative abundance of the magic gas there (950,000 ppmv) is 2375 times greater than here (400 ppmv).
The prevalence of heavier gases should give us a clue. The lighter ones are either not attracted strongly enough or are repelled. Even the oxygen found in rocks is heavier than on Earth.
Less mass, less gravity, less atmosphere, we notice the same thing on the moon. When did it happen? When it formed. Who’s to blame? Not enough meteorite to build a large enough planet.
It is worth noting that too much mass, ie gravity also is deadly to large organisms like us. Also if we rotated only twice a year as Mercury and Venus, we would not be here. Our star is also not normal. If it was normal it would run with the pack in one of the arms of the milky way instead of cutting across. It is this that gives us the dark nights and the ability to study the universe.
Velikovsky lives!
/Mr Lynn
Berényi Péter says:
July 19, 2013 at 4:47 am
Is it scientific reporting? Are they not supposed to report isotopic ratios, error bars included? Why to keep numbers resulting from research done on taxpayers’ money behind a paywall?
What does “heavy isotopes of carbon and oxygen are both enriched” actually mean?
The “top” vs “bottom” argument has to do with whether Mars’ atmosphere was drawn off through fractionation effects that heat atmospheric gases causing say CO2 with Carbon 12 as the stable carbon isotope in the molecule to migrate toward the upper atmosphere. That would leave excess C-13 in the remaining CO2. If instead chilling of the planet caused the gas to cool and condensed the heavier isotopes would precipitate first, leaving excess C-12 in the remaining gas. The same process would affect water vapor in the same way, causing H2O with the lighter O-16 isotope to rise in the atmosphere preferentially to H2O with one or two O-18 atoms in the mix. There ought to excess deuterium in the remaing H2O as well as 0-18.
Neither of those suggestions may be wrong though. Since there are massive ice caps, predominantly of CO2 ice at the poles, as Mars cooled, the atmosphere must have thinned as is CO2 froze out, leaving a light-isotope CO2 in excess in the atmosphere. Meanwhile solar radiation would work its opposite magic on what gas remained in the atmosphere. Once the system reached a quasiequilibrium where the incoming solar energy was adequate to maintain a thin atmosphere, the solar fractionation effect would dominate, leaving an excess of heavy-isotope CO2. So, really, the experiment is not conclsuive at all about where Mars’ atmosphere went.
Personally, I think testing the surface sediments for evidence of excess oxidation seems to be a more interesting question. Oxygen is chemically reactive and here on earth, exists as a free gass almost solely through the action of green plants. The major banded iron ore bodies document the changing composition of earth’s atmosphere as living organisms pumped O2 out and free iron in the oceans reacted with it and precipitated out as hematite. What I want to know is whether there is evidence that Mars’ atmosphere ever contained excess oxygen. That would really be interesting.
“It suggests that the planet’s atmosphere escaped from the top, rather than due to the lower atmosphere interacting with the ground, NASA’s web story states.”
Which leaves the question, why did this happen?
“duh? loss through interaction with the ground? whoever suggested that?”
I could imagine interaction with the ground means the atmosphere interacted to produce minerals and such. It seems like a reasonable idea to me.
You put a lot of faith in NASA scientists considering they’re wrong about pretty much everything. I’m skeptical they’re right about anything about Mars’s history. Here’s an article about NASA’s misunderstanding of Martian dust storms.
http://www.thunderbolts.info/wp/2013/04/30/electric-devils/
mwhite commented:
> It suggests that the planets atmosphere escaped from the top, rather than due to the lower atmosphere interacting with the ground, NASAs web story states.
>
> Which leaves the question, why did this happen?
As well as the question of whether there was any atmosphere to escape.
This discussion is starting to look very similar to the never-ending question of the bomb test results that we’ve enjoyed during all of July, which I feel is now on a hiatus only because everybody got tired.
Before we go on to discuss mysteries, what is the residence time of nitrogen in the present-day Martian atmosphere? Oxygen? CO2?
Roy A Jensen says:
July 19, 2013 at 8:51 am
Great comment about our sun. I love learning on this site!
agfosterjr says:
July 19, 2013 at 7:51 am
I know that Olympus Mons s a volcano, thank you for explaining the obvious.
It is not a usual volcano, though; there is a theory that it formed as a result of a magma shock wave produced by a collision with a large celestial body on the opposite side of Mars.
mwhite says: July 19, 2013 at 11:14 am
“It suggests that the planet’s atmosphere escaped from the top, rather than due to the lower atmosphere interacting with the ground, NASA’s web story states.”
Which leaves the question, why did this happen?
————————————————————-
mwhite: It happened because Mars has lower gravity than Earth. At a given temperature, gas molecules travel at a particular velocity (plus and minus a statistical distribution). At the same temperature, lighter gasses have a higher characteristic velocity than heavier gasses. Some of the gasses move fast enough to escape the planet’s gravity and are thus lost to space. Mars has lower gravity that Earth; therefore relatively more gasses are lost off the top. The fact that the heavier isotopes are now in greater abundance supports the theory that the lighter isotopes preferentially escaped off the top.
A competing (less popular) theory is that oxygen was tied up in chemical oxidation reactions with surface minerals, which would now be seen as a greater abundance of oxidizing minerals. That theory was hatched to explain test results from the earliest Viking landers.
I blame George W. Bush.
You know it makes sense!
Just a thought.
The evidence of liquid erosion could be evidence that, in its early stages when the atmosphere was much denser, the Martian atmospheric CO2 was ‘in balance’ with liquid CO2 in lakes, rivers and even oceans, as water is on our planet. After all Venus has 95% CO2 and very probably the earth did as well, but life has changed the atmospheric constitution.
Mr Lynn says:
July 19, 2013 at 9:17 am
“Velikovsky lives!”
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Yeah, it makes you wonder how Venus got into such a nice round orbit (eccentricity 0.006756). No celestial mechanic he. –AGF
it lost a big moon, lost molten core, lost magnetospheric protection and most of the atmosphere blew away… if the hydrogen isn’t contained there will be no water, just rust.
ferd berple says:
July 19, 2013 at 7:00 am
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When considering Ferd’s comment about night time temperatures on Venus, one should bear in mind the slow rotation of Venus. Length of day is 243 Earth days as opposed to our own day of just 24 hours.
So night on Venus receives no solar irradiance for a lenthy period and yet there is very little diurnal temperature range.
Philip Foster (Revd) says:
July 19, 2013 at 2:25 pm
Early Mars would have had to have been a pretty strange place to have harbored liquid CO2 on its surface. It forms only at pressures above 5.18 times the sea level atmospheric pressure on Earth & at −56.6 °C; it remains a normal liquid until 7380 atm at 31.1 °C.
There is chemical evidence that the liquid whose effects have been observed on ancient Mars was water.
Lack of magnetic field is no reason why a planet should lose a dense atmosphere, the current state of Venus instructs us.
Before Martian water, there was Martian ice, and numerous encounters with asteroid bodies, two of which remain captured as the Martian moons Phobos and Deimos. There may have been others, now gone. Now these bodies just slid into neat orbits around Mars? No, they initially had orbits that were greatly elliptical, with very close approaches at periapsis – which caused atmospheric disturbance, intense tidal friction and melting of the ice, and led to the loss of Mars’ atmosphere. Now both moons have nearly circular ecliptic orbits, but that of innermost moon Phobos is in a fast and unstable orbit, less than 10000km high, decaying towards breakup, planetary ring formation and possibly some future reaccretion, as it seems likely that the moon’s composition is “loose rubble”, with a high carbonaceous content. Perhaps Fred Singer may like to comment – it was once one of his primary academic interests.
Venus has no moons, and no tidal perturbations beyond those of the sun and planets. It has little interaction with solar radiation, reflecting most of it back to space. A Venusian Trenbreth would be bewailing the lack of cooling…:) Internal heating is the cause of its high temperatures, its opaque atmosphere, and the apparent recent resurfacing due to volcanic activity.
With the amazing data now obtained, all the known planets are much weirder than was imagined 60 years ago, and yet, guess after guess may bring us closer to some idea of how they came about. Runaway global warming is not yet a good hypothesis for anywhere in the Solar System, and come to think of it, internal heating via the ocean/mantle interface, and the only forcing being geovolcanic on earth, seems much more attractive than Solar variation and gradual atmospheric modifications causing climate changes.
milodonharlani says:
“It forms only at pressures above 5.18 times the sea level atmospheric pressure on Earth & at −56.6 °C; it remains a normal liquid until 7380 atm at 31.1 °C.”
– I think you mean ‘a normal gas’?
Temperatures on early Mars would still have been around -100C (well below Ct of CO2) – remember the early sun was only 70% of its current brightness, which makes liquid water on Mars improbable surely?
There is liquid CO2 on earth at the bottom of ocean trenches which indeed produce very high pressures (an aside: this is why the oceans are effectively saturated with CO2 and there ‘more CO2’ cannot alter the pH of seawater).
I meant normal liquid, as I wrote. Beyond its critical point at the indicated pressure & temperature, it becomes a supercritical fluid:
http://en.wikipedia.org/wiki/File:Carbon_dioxide_pressure-temperature_phase_diagram.svg
Philip Foster (Revd) says:
July 20, 2013 at 2:34 pm
Despite the faint young sun paradox, the evidence for running, liquid water is strong:
http://redplanet.asu.edu/?p=2485
Evidence of neutral pH water on ancient Mars:
http://www.universetoday.com/102744/opportunity-rover-discovers-martian-habitable-zone-favorable-for-pre-biotic-chemistry/
Yet another authoritative pronouncement from the Ministry of Science.
Maybe a more obvious consideration for a thinner atmosphere is that huge 9 mile deep hole in Mars, you know Hellas Planitia, also known as the Hellas Impact Basin.
And yes, the idea of the bottom out theory is also still viable given what we see on Earth right under our feet and oceans, you know Carbonate Deposits like lime stone and coral reefs… How many tons of CO2, i.e. Carbon and Oxygen are locked up in the Great Barrier Reef off of Australia is just one example? Mars was said to have lots of liquid water at one time.
And there is still the idea of oxidation with all that iron that seems to be abundant on Mars…Fe2O3
So here are at least processes that could have been active to sequester the atmosphere.
“The isotope data are unambiguous and robust, having been independently confirmed by the quadrupole mass spectrometer and the tunable laser spectrometer, two of the SAM suite instruments,”
Anytime anyone uses the Imprimatur Fallacy in it’s various forms, my BS meter immediately spikes.
Why is Earth the standard anyway given the biologic processes? Just because heavy isotopes are under represented in the our atmosphere doesn’t mean it’s the standard for another explanation. Vulcanism pumps out heavy isotopes as well.
CK says:
July 20, 2013 at 12:21 pm
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The quacks come out of the woodwork when Watts posts something about ET atmospheres. One says Venus reflects nothing; another says it reflects everything–internal heat is responsible (while admitting negligible tidal friction). So CK, is core radiation responsible? Then why does the Venus atmosphere rotate? Can you provide sources for any of your claims? I’d settle for arguments, but you provide none. Mars moons brought into round orbits by atmospheric friction? NASA used the atmosphere to capture the Apollo ships. I don’t think you know what you’re talking about, but you wouldn’t be the first. –AGF
Duster says:
July 19, 2013 at 10:14 am
I’m with Duster on how “robust” the evidence is in isotopic ratios for simple loss of the atmosphere. Nowhere do they make reference to frozen CO2 and H20 that is in abundance. These frozen deposits early on must have preferentially sequestered heavy C and O leaving lighter isotopes enriched in the atmosphere and thus more vulnerable to loss to space than it otherwise would be. Its still a loss to space but no mention of the sequestration in ice is sloppy science. They took samples in the north polar region and must have the data, but, having worked in a government bureaucracy at one time, I imagine the other work was by a different “division” of the organization.
ferd berple says:
July 19, 2013 at 7:00 am
Of the three, Venus has the densest atmosphere, yet has no magnetic field to protect the atmosphere from the solar wind. Something overlooked in the explanation of how planets lose their atmosphere.
Actually according to the data looks like Mars, Earth and Venus, all lose atmosphere at about the same pace “Each of the three planets is losing roughly a ton of atmosphere to space every hour.”
The Earth magnetic field does not protect the atmosphere from being lost, only the lost is happening in other areas, around the poles “atmospheric ions enough that they escape up out of the poles, forming Earth’s “polar ion outflows.” ”
http://www.space.com/11187-earth-magnetic-field-solar-wind.html
quote “The isotope data are unambiguous and robust”. When NASA says their research is robust, I’m suspicious. I can’t trust anyone who proclaims their perfect knowlage.