Curiosity: no methane found on Mars – yet

From NASA JPL, no evidence of Methane found in first tests.

Potential Sources and Sinks of Methane on Mars – If the atmosphere of Mars contains methane, various possibilities have been proposed for where the methane could come from and how it could disappear.
PASADENA, Calif. — NASA’s car-sized rover, Curiosity, has taken significant steps toward understanding how Mars may have lost much of its original atmosphere.

Learning what happened to the Martian atmosphere will help scientists assess whether the planet ever was habitable. The present atmosphere of Mars is 100 times thinner than Earth’s.

A set of instruments aboard the rover has ingested and analyzed samples of the atmosphere collected near the “Rocknest” site in Gale Crater where the rover is stopped for research. Findings from the Sample Analysis at Mars (SAM) instruments suggest that loss of a fraction of the atmosphere, resulting from a physical process favoring retention of heavier isotopes of certain elements, has been a significant factor in the evolution of the planet. Isotopes are variants of the same element with different atomic weights.

Initial SAM results show an increase of five percent in heavier isotopes of carbon in the atmospheric carbon dioxide compared to estimates of the isotopic ratios present when Mars formed. These enriched ratios of heavier isotopes to lighter ones suggest the top of the atmosphere may have been lost to interplanetary space. Losses at the top of the atmosphere would deplete lighter isotopes. Isotopes of argon also show enrichment of the heavy isotope, matching previous estimates of atmosphere composition derived from studies of Martian meteorites on Earth.

Scientists theorize that in Mars’ distant past its environment may have been quite different, with persistent water and a thicker atmosphere. NASA’s Mars Atmosphere and Volatile Evolution, or MAVEN, mission will investigate possible losses from the upper atmosphere when it arrives at Mars in 2014.

With these initial sniffs of Martian atmosphere, SAM also made the most sensitive measurements ever to search for methane gas on Mars. Preliminary results reveal little to no methane. Methane is of interest as a simple precursor chemical for life. On Earth, it can be produced by either biological or non-biological processes.

Methane has been difficult to detect from Earth or the current generation of Mars orbiters because the gas exists on Mars only in traces, if at all. The Tunable Laser Spectrometer (TLS) in SAM provides the first search conducted within the Martian atmosphere for this molecule. The initial SAM measurements place an upper limit of just a few parts methane per billion parts of Martian atmosphere, by volume, with enough uncertainty that the amount could be zero.

“Methane is clearly not an abundant gas at the Gale Crater site, if it is there at all. At this point in the mission we’re just excited to be searching for it,” said SAM TLS lead Chris Webster of NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “While we determine upper limits on low values, atmospheric variability in the Martian atmosphere could yet hold surprises for us.”

In Curiosity’s first three months on Mars, SAM has analyzed atmosphere samples with two laboratory methods. One is a mass spectrometer investigating the full range of atmospheric gases. The other, TLS, has focused on carbon dioxide and methane. During its two-year prime mission, the rover also will use an instrument called a gas chromatograph that separates and identifies gases. The instrument also will analyze samples of soil and rock, as well as more atmosphere samples.

The Five Most Abundant Gases in the Martian Atmosphere – This graph shows the percentage abundance of five gases in the atmosphere of Mars, as measured by the Quadrupole Mass Spectrometer instrument of the Sample Analysis at Mars instrument suite on NASA’s Mars rover in October 2012. The season was early spring in Mars’ southern hemisphere, and the location was inside Mars’ Gale Crater, at 4.49 degrees south latitude, 137.42 degrees east longitude. The graph uses as logarithmic scale for volume percentage of the atmosphere so that these gases with very different concentrations can all be plotted. By far the predominant gas is carbon dioxide, making up 95.9 percent of the atmosphere’s volume. The next four most abundant gases are argon, nitrogen, oxygen and carbon monoxide. Researchers will use SAM repeatedly throughout Curiosity’s mission on Mars to check for seasonal changes in atmospheric composition. Image Credit: NASA/JPL-Caltech, SAM/GSFC
“With these first atmospheric measurements we already can see the power of having a complex chemical laboratory like SAM on the surface of Mars,” said SAM Principal Investigator Paul Mahaffy of NASA’s Goddard Space Flight Center in Greenbelt, Md. “Both atmospheric and solid sample analyses are crucial for understanding Mars’ habitability.”

SAM is set to analyze its first solid sample in the coming weeks, beginning the search for organic compounds in the rocks and soils of Gale Crater. Analyzing water-bearing minerals and searching for and analyzing carbonates are high priorities for upcoming SAM solid sample analyses.

Researchers are using Curiosity’s 10 instruments to investigate whether areas in Gale Crater ever offered environmental conditions favorable for microbial life. JPL, a division of the California Institute of Technology in Pasadena, manages the project for NASA’s Science Mission Directorate, Washington, and built Curiosity. The SAM instrument was developed at Goddard with instrument contributions from Goddard, JPL and the University of Paris in France.

For more information about Curiosity and its mission, visit: and .

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November 6, 2012 8:03 am

Wow! 95% CO2? They must be “burning up”…with Martian Warming (MW). Must be all those old SUV’s we’ve disposed of on MARS. Bummer…

November 6, 2012 8:04 am

Heh, the AGWs will have a field day with that graph! “See! The Martians drove lots of cars and stuff and filled up their whole atmosphere with CO2 ‘n now they’re all dead ‘n gone jes’ like we’s gonna be if’n we don’ ‘lect Al Gore in 2016!

Al Gore
November 6, 2012 8:05 am

What!! 96% CO2! The temperatures must be upwards of a million degrees on the surface of Mars!

November 6, 2012 8:33 am

Surprised to see Oxygen (0.14%) in the atmosphere. Any theories? Is it long term implying a fully oxidised soil or is it short term from the dissassociation of water implying Mars is still losing hydrogen?

Jim G
November 6, 2012 8:35 am

CH4 + 2 O2 gives CO2 + 2 H2O. So, it may have been there at one time since both CO2 and H2O are known to be there now.

November 6, 2012 8:49 am

We will hear many theories , some wild and some not , but I for one will not accept any of them as these same people can’t seem to understand what is happening here on earth . So are you really going to believe what they tell you about a place they can never visit ? They should all be working on developing better pesticides to counter the huge influx of new pests being imported into the US and then concentrate on improving the ability of farmers to produce more and better crops . But they probably wouldn’t do any good in that field either .

November 6, 2012 8:51 am

I wonder if the Martian government could borrow some atmosphere from Venus.

Hector Pascal
November 6, 2012 8:55 am

A frozen rock with solid CO2 deposits and no free water. It’s the last place in the solar system that I’d go looking for life, unless I had an unemployed rent-seeking space agency kicking cans up the street.

Coach Springer
November 6, 2012 9:00 am

Looks like a hydrogen deficiency. No methane and very little water. Hydrogen, carbon, and oxygen needed. Only possible explanation: After the Martian SUVs converted every last ounce of energy to CO2 and H2O, earth gravity stole all of the water. In space, no one can hear the giant sucking sound.

November 6, 2012 9:03 am

I think we need a few more tea leaves before we can start reading them. Data good, preliminary interpretation, not so much …

Gary D.
November 6, 2012 9:05 am

I thought the Mars atmosphere was blown off by the solar wind after the magnetosphere died. I understood Mars had a molten core like earth, but smaller, and it cooled and hardened. That ended the magnetosphere.

Gene Selkov
November 6, 2012 9:13 am

Miles Mathis just published a paper in which he explains why the Earth has the atmosphere it has and why Mars probably never had an atmosphere to speak of.

November 6, 2012 9:13 am

Apparently Richard Branson posted a picture of a sun rise on mars, and someone made one of the most stupid comments I have ever read!
Quote “so pretty I never knew mars had a sun”

November 6, 2012 9:46 am

AlanG says:
November 6, 2012 at 8:33 am
Surprised to see Oxygen (0.14%) in the atmosphere. Any theories? Is it long term implying a fully oxidised soil or is it short term from the dissassociation of water implying Mars is still losing hydrogen?

The simplest explanation continues to be water vapor dissociating. But, there are lots of processes on Mars that no one really has a handle on. There are good images of sinkholes that can’t be the result of limestone dissolving in ground water. The best explanations are either water ice or CO2 ice subliming. Given the temperatures in some regions where these holes have been observed, water ice seems more reasonable. That would mean that there could be very considerable deposits of nearly pure ice buried under the apparent mineral surface.

November 6, 2012 9:52 am

How did (if it did) a hotter sun affect the heavier planets a billion years ago? Would a cooling sun, assuming it has cooled as its gotten older, affect the iron cores?

November 6, 2012 10:10 am

I was of the impression NASA was busy teaching muslims about technology and torturing data?
And they have time for this?

James at 48
November 6, 2012 10:11 am

Is Earth’s atmosphere also lossy? Is there going to be a tipping point … no … no … not THAT tipping point … the other one. The really, really, really bad one.

P. Solar
November 6, 2012 10:27 am

“Initial SAM results show an increase of five percent in heavier isotopes of carbon in the atmospheric carbon dioxide compared to estimates of the isotopic ratios present when Mars formed. ”
Astounding finding. And tell me what is the expected accuracy of estimating the isotopic ration “when Mars was formed”.
Get real !!

November 6, 2012 10:31 am

“Gene Selkov says: etc”
There seems to be some circular logic in that paper… In order for the theory to work, the number must be X, so assume the number is X … since the number is X the theory works.
I do find it strange that Mars and Venus both have primarily CO2 atmospheres while Earth has a primarily N2 atmosphere. And I agree that current theory on why and how is also circular.

Tom O
November 6, 2012 10:36 am

The reason for the two strange atmospheres – Venus and Mars – is that that many years ago, Venus and Mars were married. Then, after a bitter divorce, Venus took Mars to the cleaners, and her lawyer got here 98% of Mars’ atmosphere. You can’t trust those female planets, or their lawyers.

November 6, 2012 10:39 am

Duster D- Thanks for your reply. Makes sense given how reactive oxygen is.

george e. smith
November 6, 2012 10:40 am

Well I’m sure the absence of methane is a big disappointment to those who think Mars might be or had been teeming with life.
Obviously, they need to send a bigger truck up there with better instruments.
Seriously though; the feat of getting that gizmo up there and functioning, is itself a triumph. Can’t help but believe they will learn much that is valuable information we didn’t have before.
I happen to be one of those who don’t believe the universe is full of civilizations all over the place; or even uncivilizations like we have on earth.
In my view, the energetical improbabilities of all of the necessary chemical syntheses, in the required order, to get to a living organism, is enough to swamp all of the myriads of earthlike planets that must be out there; not one of which we have yet found.
When they get the very first binary digit of scientific evidence of life of any sort, outside the very thin shell it inhabits on earth; I’ll sit up and take notice. In the meantime, it is simply an endless research grant income stream. (for someone)

November 6, 2012 10:57 am

Re heavier isotopes of Carbon etc. Main cause of their formation, I assume, is the huge bombardment by cosmic rays, due to 1. little magnetic field and 2. very thin atmosphere.

November 6, 2012 11:03 am

Regarding lack of methane: this strongly suggests no life on Mars – even in the past. Primordial methane is a very unlikely component of the early atmospheres of the inner rocky planets (there is none on Venus for example) – unlike the outer gas giants. Earth’s methane is a result of having a biosphere and is most unlikely to have been present before early life formed.

November 6, 2012 11:41 am

Thanks Tom O. Now I know why Mars looks so angry.

Michael J. Dunn
November 6, 2012 12:38 pm

Mars’s atmosphere is simply “boiling” away, for the same reason that helium in Earth’s atmosphere continually “boils” away into space: the thermal Boltzmann distribution of molecular speeds has a fraction greater than the Earth’s escape velocity (11.2 km/sec). That fraction exits into space, never to return, and thermal equlibrium continues to fill the fraction from other helium molecules available.
Mars’s escape velocity is 5.0 km/sec, so for the same temperature as on Earth (to make the calculation easier), a molecule of atomic mass 20 can escape from Mars as permanently as helium from Earth. Methane has an atomic mass of 16. Carbon dioxide has an atomic mass of 44. Nitrogen is 28 and oxygen is 32, but oxygen is already bound up with carbon. Carbon monoxide has an atomic mass of 28. So, it is no surprise there is no methane (there would only be a surprise if methane was detected), and no surprise that the remaining molecules have a higher fraction of heavy isotopes; the ligher isotopes are prone to migrate into space.
The other effect is solar UV radiation, which will split any hydrogen from water, leaving behind the oxygen (and which was probably responsible for the formation of the oxygen in our atmosphere). Since the atmosphere of Mars is mostly CO2, there is not much oxygen available to be transformed into ozone, so the solar UV goes all the way to the Martian surface. Water can survive under those conditions only if it is protected from sunlight (i.e., under ground).

D Böehm
November 6, 2012 12:46 pm

Michael J. Dunn,
Very good explanation, thanks. Can you explain why Titan has methane seas and methane in it’s atmosphere? Colder temperature, perhaps?

November 6, 2012 12:48 pm

…compared to estimates of the isotopic ratios present when Mars formed.
So the actual measurement is off from some wild assed guess? SCIENCE!!!

Gary Pearse
November 6, 2012 2:09 pm

Mustn’t read too much into the presence or absence of methane – farther out we have Triton with methane seas! Also, did they try sniffing the atmosphere on the Gobi desert – might not be much there either and what there is would have blown in from friendlier organically abundant climes. A desert of a few hundred thousand km^2 should have little. Heck the earth only has 1.6 ppm. If Mars had the same proportion in its atmosphere, which is 1% of that of the earth, it would have 0.016 ppm – how many molecules per cc is that for the Curiosity sniffer? Lets see one mole has 6*10^23 molecules…..hmm… and a litre of atmos = 0.02/44 has 4.5*10^-4(6*10^23) =2.7*10^20 molecules of atmosphere per litre and with no life, it would be reasonable to expect that that methane would have less than 1% of the earth’s fecund proportion of~1 ppm so there would be ~10^12 molecules of methane per litre or ~~10^12/10^22 * 16gs (per mole of methane) ~~~2*10^-6 gs per litre of atmosphere sampled – say 2*10^-9 grams/litre i.e. 2 nanograms/litre. Have I got that right?

November 6, 2012 2:35 pm

We have not the slightest evidence for life anywhere else. It’s just us. This is an awesome responsibility. Preserve life here and spread it to a lifeless universe.

November 6, 2012 4:10 pm

Fascinating. I just read in wikipedia article on the atmosphere of Venus “the atmospheric pressure and temperature at about 50 km to 65 km above the surface of the planet is nearly the same as that of the Earth”. Considering that Venus is much closer to the Sun than Earth is (90% more incident solar radiation), and is 96.5% CO2, doesn’t that pretty much disprove the idea that CO2 causes warming?

November 6, 2012 5:00 pm

Maybe Martians are just too polite to fart.

November 6, 2012 8:45 pm

Jim G, the reaction does not happen unless there are the right conditions. For methane to burn in air there must be a) a source of ignition or sufficient temperature of the mix ie about 650C and b) sufficient methane in the mix -the lean limit is 46% of stoichiometric.(in our earthly atmosphere the bottom limit is about 10% by volume). The IPCC claims about methane are wrong.
Mars has a lower gravity than earth (about 37%) so the lighter gases such as methane (MW16) and water vapor (MW18) are lost to space.

November 7, 2012 3:23 am

I wonder if such a “Sample Analysis at Venus (SAV) ☺” was included in the Venus Express mission. The reason I ask is I came upon a quite surprising statement in a book, “Pioneering Venus — A Planet Unveiled” (1996) by some apparent experts (manager of Pioneer Venus mission and the lead scientist) in this area and here is the curiosity:
Starting at page 7: (my highlighting)

Soviet space probes that penetrated the Venusian atmosphere (see Chapter 7) confirmed Earth-based observations, and Veneras 4 and 5 suggested a concentration of 97% carbon dioxide. Radio-occultation data confirmed these probe measurements. However, temperature and pressure measurements from probes differed from radio-occultation measurements in a way that seemed best explained by supposing that Venus’ atmosphere contained only 70% carbon dioxide. Also, if there were large amounts of argon in the atmosphere, carbon dioxide could be as low as 25% and still satisfy all the measurements astronomers made from Earth.
The amount of carbon dioxide in a planetary atmosphere affects how scientists interpret the planet’s microwave spectrum. With accepted percentages of carbon dioxide, microwave observations indicated as much as 0.5% water vapor below Venus’ clouds. Instruments on Veneras 9 and 10 provided data that suggested 0.1% water vapor below the clouds. At the cloud tops, however, they indicated only 0.0001% water vapor. Of course, there was the chance that if the atmosphere contained another gas that was a poor absorber of microwaves, the planet’s atmosphere could contain even more water. If that were true, scientists might account for the larger amounts of water that Veneras 4 and 5 measured at the surface.

Maybe instead of argon how about, nitrogen, or both, or others? Isn’t nitrogen also microwave transparent? Since this book was published after the entire sequence of Venera, Mariner, Cosmos and Pioneer Venus missions it give it some credence and does this great possible discrepancy in the concentration of CO2 on Venus still exist? If so that concludes the last piece of data I have searched for to wrap up some work in this area of planetary atmospheres. This does seem to say yes, unless there does exists a more recent direct gas analyses have been performed by Venus Express, so far I can find no reference.
So I hate to say it but when I read such NASA PR flashes as this one of a Mars breakthrough I just have to wonder what assumptions have been made, shortcomings in methods used and ‘consensuses’ reached underlying each and every piece of data. Seems so much is never honestly supplied to the public upfront and that’s a shame.

November 7, 2012 7:40 am

Mike Borgelt says:
November 6, 2012 at 2:35 pm
We have not the slightest evidence for life anywhere else. It’s just us.
how did we get here? in what respect are conditions on earth unique in an infinite universe?
How can the universe be infinite and not contain an infinite number of identical earths? Isn’t the earth simply a finite combination of matter and energy? No matter how many dice you throw at one time, if the number of dice is finite eventually the same combination will repeat. Given an infinite number of throws, the same combination will repeat an infinite number of times.

Crispin in Waterloo
November 7, 2012 9:14 am

@Gary D. says:
“I thought the Mars atmosphere was blown off by the solar wind after the magnetosphere died. I understood Mars had a molten core like earth, but smaller, and it cooled and hardened. That ended the magnetosphere.”
That sound familiar. The escape velocity argument as pretty good too.
Re the 2 nanograms, it would help if you worked it out in ppm because I can’t tell if you have a standard litre of Earth air mass or a vacuous litre of Mars air.
I will add that a nearby supernova may have removed a lot of atmosphere at once – they can be pretty terrifying. The combination of a low magnetic field, solar wind and supernova might trigger something irreversible like the disruption of an ozone layer. I favour the water-is-buried notion, with the O2 oxidising the iron available in the crust surface. Hence all that red iron oxide. The sink holes are interesting but not if they are billions of years old.

Michael J. Dunn
November 7, 2012 11:59 am

D. Boehm: Yep. Colder temperatures will reduce the molecular speeds.
On Mars, if the primordial atmosphere had been water vapor and methane, the likely processes would have been: (1) some methane lost directly to space, and (2) water split into hydrogen and oxygen by solar UV, which would then allow the oxygen to form ozone from the same UV, which would then chemically react (not combust) with the methane to form CO2 and water, and the water gets recycled in the process. Net result: no methane, plenty of CO2.

Gene Selkov
November 7, 2012 2:05 pm

KevinM says: “I do find it strange that Mars and Venus both have primarily CO2 atmospheres while Earth has a primarily N2 atmosphere.”
Well, we do see that CO2 precipitates on Earth, N2 and O2 are nearly equally bouyant, and everything lighter than O2 escapes. So in our present conditions, we can’t have a primarily CO2 atmosphere. Also, because there is no obvious source of N2 on Earth, it must be of cosmic origin and so must be in a stationary flux. It is probably in a stationary flux around Mars as well, but Mars’s ability to pool it is not as good. What really seems strange is that Mars has very little of C02, while Venus has a lot. But then, Venus is an upside-down planet — how much stanger can a planet be?

Brian H
November 7, 2012 11:07 pm

I seem to recall transient readings of CH4 “wisps” on Mars from orbit. The thought at the time was that they must be biogenic, as CH4 lasts very little time unless continuously replenished. So readings are likely to be site-specific, not whole-atmosphere.

November 8, 2012 1:18 am

Fred berple……sorry, but not true. The universe is not infinite, it’s big, sure, but not infinite otherwise it could not expand and according to our observations that’s exactly what it is doing.
Also, even though maths may say that it is ‘probable’ that other planets have the conditions requisite for life, that doesn’t mean that life exists on them. We ‘could’ be the first and only.

November 8, 2012 9:27 am

The amount of Nitrogen is surprising and quite hopeful for Terraforming since plants require N2 in addition to CO2 & H2O.

Jim G
November 8, 2012 12:34 pm

mizimi says:
November 8, 2012 at 1:18 am
“Fred berple……sorry, but not true. The universe is not infinite, it’s big, sure, but not infinite otherwise it could not expand and according to our observations that’s exactly what it is doing.”
Previous theory was that the universe was finite in matter and energy but “unbounded”. Not so much any more. See Bob Beman’s article in the last issue of Astronomy Magazine as apparently observational data over the last 10-15 years keeps adding up to an infinite universe according to some heavy hitter types from CalTech/MIT etc. In an infinite universe, big bangs, cosmic expansion and even the physical laws themselves might just be “local” in nature and apply only to our infinitesimally small sector of the universe. It seems that every time we get some better observational data we find out much of what we thought was true is wrong.

Lars P.
November 8, 2012 2:25 pm

James at 48 says:
November 6, 2012 at 10:11 am
Is Earth’s atmosphere also lossy? Is there going to be a tipping point … no … no … not THAT tipping point … the other one. The really, really, really bad one.
Well, I saw some contradictory posts, so not sure how much of a consensus we have here, or was I looking at the wrong place?
“Each of the three planets” (Venus, Earth and Mars) ” is losing roughly a ton of atmosphere to space every hour.
” Strangeway explains this in terms of momentum. The solar wind loses some of its momentum when it runs into any planet. [Photos: Auroras Dazzle Northern Observers]
Basic physics suggests that this momentum has to go somewhere, and according to Strangeway, it goes into the polar region atmosphere to energize ions there to velocities sufficient to escape Earth’s gravity. The presence of a magnetic field changes the mechanism for this momentum transfer, but the end result is similar.”
whereas here:
“Earth’s magnetic field provides vital protection”
“They found that while the pressure of the solar wind increased at each planet by similar amounts, the increase in the rate of loss of martian oxygen was ten times that of Earth’s increase. “

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