Remaining Martian atmosphere still dynamic

Apr 08, 2013
This image shows the first holes into rock drilled by NASA's Mars rover Curiosity, with drill tailings around the holes plus piles of powdered rock collected from the deeper hole and later discarded after other portions of the sample had been delivered to analytical instruments inside the rover. Image: NASA/JPL-Caltech/MSSS

(Phys.org) —Mars has lost much of its original atmosphere, but what's left remains quite active, recent findings from NASA's Mars rover Curiosity indicate. Rover team members reported diverse findings today at the European Geosciences Union 2013 General Assembly, in Vienna.

Evidence has strengthened this month that Mars lost much of its original atmosphere by a process of gas escaping from the top of the atmosphere.

Curiosity's Sample Analysis at Mars (SAM) instrument analyzed an atmosphere sample last week using a process that concentrates selected gases. The results provided the most ever made of isotopes of in the . are variants of the same element with different . "We found arguably the clearest and most robust signature of atmospheric loss on Mars," said Sushil Atreya, a SAM co-investigator at the University of Michigan, Ann Arbor.

This illustration shows the instruments and subsystems of the Sample Analysis at Mars (SAM) suite on the Curiosity Rover of NASA's Mars Science Laboratory Project. Image: NASA/JPL-Caltech

SAM found that the Martian atmosphere has about four times as much of a lighter (argon-36) compared to a heavier one (argon-38). This removes previous uncertainty about the ratio in the Martian atmosphere from 1976 measurements from NASA's Viking project and from small volumes of argon extracted from . The ratio is much lower than the solar system's original ratio, as estimated from argon-isotope measurements of the sun and Jupiter. This points to a process at Mars that favored preferential loss of the lighter isotope over the heavier one.

Curiosity measures several variables in today's Martian atmosphere with the Rover Station (REMS), provided by Spain. While daily air temperature has climbed steadily since the measurements began eight months ago and is not strongly tied to the rover's location, humidity has differed significantly at different places along the rover's route. These are the first systematic measurements of humidity on Mars.

Trails of have not been seen inside Gale Crater, but REMS sensors detected many whirlwind patterns during the first hundred Martian days of the mission, though not as many as detected in the same length of time by earlier missions. "A whirlwind is a very quick event that happens in a few seconds and should be verified by a combination of pressure, temperature and wind oscillations and, in some cases, a decrease is ultraviolet radiation," said REMS Principal Investigator Javier Gómez-Elvira of the Centro de Astrobiología, Madrid.

As the Sample Analysis at Mars (SAM) suite of instruments on NASA's Curiosity Mars rover heats a sample, gases are released (or "evolved") from the sample and can be identified using SAM's quadrupole mass spectrometer. Image: NASA/JPL-Caltech

Dust distributed by the wind has been examined by Curiosity's laser-firing Chemistry and Camera (ChemCam) instrument. Initial laser pulses on each target hit dust. The laser's energy removes the dust to expose underlying material, but those initial pulses also provide information about the dust.

"We knew that Mars is red because of iron oxides in the dust," said ChemCam Deputy Principal Investigator Sylvestre Maurice of the Institut de Recherche en Astrophysique et Planétologie in Toulouse, France. "ChemCam reveals a complex chemical composition of the dust that includes hydrogen, which could be in the form of hydroxyl groups or water molecules."

This image shows the ratio of the argon isotope argon-36 to the heavier argon isotope argon-38, in various measurements. Image: NASA/JPL-Caltech

Possible interchange of water molecules between the atmosphere and the ground is studied by a combination of instruments on the rover, including the Dynamic Albedo of Neutrons (DAN), provided by Russia under the leadership of DAN Principal Investigator Igor Mitrofanov.

For the rest of April, Curiosity will carry out daily activities for which commands were sent in March, using DAN, REMS and the Radiation Assessment Detector (RAD). No new commands are being sent during a four-week period while Mars is passing nearly behind the sun, from Earth's perspective. This geometry occurs about every 26 months and is called Mars solar conjunction.

"After conjunction, Curiosity will be drilling into another rock where the rover is now, but that target has not yet been selected. The science team will discuss this over the conjunction period." said Mars Science Laboratory Project Scientist John Grotzinger, of the California Institute of Technology, Pasadena.

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User comments : 5

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gwrede
1 / 5 (1) Apr 08, 2013
Excellent article.
Jonseer
1.7 / 5 (6) Apr 09, 2013
I really have to wonder about the perspective of the science that says Mars has lost most of its atmosphere when so much frozen carbon dioxide sits at both polls and below the ground PERMANENTLY (at least for the long term) frozen out of the atmosphere.

Yes the information they have is correct, but I'd say it's incorrect to say Mars lost most of its atmosphere and by inference say that is why the atmosphere is so thin today.

If the frozen co2 sublimated, Mars would have a decently thick atmosphere.

Were that to sublimate, it would warm the surface of the planet significantly allowing even more thickening thanks to water vapor becoming able to linger and maintain the warmth.
GSwift7
3 / 5 (4) Apr 09, 2013
SAM found that the Martian atmosphere has about four times as much of a lighter stable isotope (argon-36) compared to a heavier one (argon-38).


That is backwards. It has four times as much of the heavier isotope, not the lighter.

If the frozen co2 sublimated, Mars would have a decently thick atmosphere.

Were that to sublimate, it would warm the surface of the planet significantly allowing even more thickening thanks to water vapor becoming able to linger and maintain the warmth


No, try looking at the wiki page on the martian polar ice caps for some true information about them before you post anything else:

http://en.wikiped...ice_caps

They are made mostly of water. All of the northern martian co2 melts each summer, and the south pole only keeps a thin layer year round. It would take many times more ice to thicken the atmosphere the way you are thinking.
Osiris1
1 / 5 (3) Apr 09, 2013
Methinks the ice is there, under the red dust that protects it. This was found by one of our landers that did a little digging. It is possible that the northern ocean is still there as well. Question is: Is it frozen to all the way to the bottom? Somehow I find it difficult to believe that, and as well find it difficult to believe that Mars is geologically dead, its core frozen. A meteor strike of sufficient size may wake the place up in surprising ways especially if it is an iceball with a core of iron alloys and rare earths. Not inconceivable if a refugee from the Oort cloud. Of course such a visitor would, and had better, arouse concern from our little world lest the next on 'visit' US! Might even rouse us off our cheapskate butts to get to be serious about real space exploration. It won't be cheap, and progress will be often paid for in blood; but then the early seafarers were not pantywaist pacifist apathetics, and they suffered too.
GSwift7
3 / 5 (4) Apr 10, 2013
Methinks the ice is there, under the red dust that protects it. This was found by one of our landers that did a little digging. It is possible that the northern ocean is still there as well. Question is: Is it frozen to all the way to the bottom? Somehow I find it difficult to believe that, and as well find it difficult to believe that Mars is geologically dead, its core frozen


Curiosity has a ground-penetrating water detector, and it's seeing only trace amounts of water at that location. We can see plenty of deep craters and exposed strata all over mars. Surely there would be visible evidence of any massive underground water.

Mars is geologically dead at its surface, more or less. The inside of mars is still cooling, so there's bound to be some minor activity. However, we can tell by the age of surface features that the surface of mars has remained mostly unchanged for a very long time. There's no sign of anything newer than millions of years old, except for impacts.