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Curiosity finding reduces hopes of finding life on Mars


September 24, 2013

Lab demonstration of the Tunable Laser Spectrometer (Image: NASA/JPL-Caltech)

Lab demonstration of the Tunable Laser Spectrometer (Image: NASA/JPL-Caltech)

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NASA’s Curiosity Mars rover has detected no methane on Mars after more than a year of extensive testing of the Martian atmosphere using the robot explorer’s Sample Analysis at Mars (SAM) laboratory. Since methane is a key indicator for the presence of biological activity, its absence throws into question the notion that there may be life on Mars today.

The simplest of the hydrocarbons, methane is also the most abundant in the Solar System, making up a large fraction of the atmospheres of the gas giants Jupiter, Saturn, Uranus, and Neptune. On Earth, natural gas is mostly methane and it is produced in surprisingly large quantities by bacteria and other organisms. It occurs at such a basic level of biology that its presence is regarded by scientists as a key indicator that life is present, though it can occur from other sources.

The frustrating and surprising thing about Curiosity’s findings isn't that it found very little methane, but that it found none down to the limits of its ability to detect, which NASA says is well below 1.3 parts per billion. Previous reports had put the presence of methane at around 45 parts per billion, but those were the result of observations by Earth-based telescopes and orbiting spacecraft.

The advantage that Curiosity has is the Tunable Laser Spectrometer, which is part of the SAM laboratory, the largest of the 10 experimental packages carried by the unmanned probe. The spectrometer collects and concentrates the Martian atmosphere inside of itself before shining an infrared laser back and forth through the sample using a series of mirrors. This allows it to measure how much light is absorbed by the gases present and measure their quantity. On six occasions between October of last year and June, Curiosity tested for the presence of Methane and found none.

"It would have been exciting to find methane, but we have high confidence in our measurements, and the progress in expanding knowledge is what's really important," says Chris Webster of NASA's Jet Propulsion Laboratory in Pasadena, California. "We measured repeatedly from Martian spring to late summer, but with no detection of methane."

Installing the  Sample Analysis at Mars (SAM) instrument in Curiosity (Image: NASA/JPL-Cal...

Installing the Sample Analysis at Mars (SAM) instrument in Curiosity (Image: NASA/JPL-Caltech)

The incredible thing about these findings isn't just the blow it serves to the hunt for life on Mars, it also indicates that the other sources of methane on the Red Planet are almost entirely absent as well. To produce such a negative result, Mars has to produce less than 20 tons of methane per year over the entire planet. That’s about as much as is produced by one 200-head herd of Earth cows.

"There's no known way for methane to disappear quickly from the atmosphere," says Sushil Atreya of the University of Michigan, Ann Arbor. "Methane is persistent. It would last for hundreds of years in the Martian atmosphere. Without a way to take it out of the atmosphere quicker, our measurements indicate there cannot be much methane being put into the atmosphere by any mechanism, whether biology, geology, or by ultraviolet degradation of organics delivered by the fall of meteorites or interplanetary dust particles."

Despite this setback, it doesn't mean that the search for life is over.

"This important result will help direct our efforts to examine the possibility of life on Mars," says Meyer, NASA's lead scientist for Mars exploration. "It reduces the probability of current methane-producing Martian microbes, but this addresses only one type of microbial metabolism. As we know, there are many types of terrestrial microbes that don't generate methane."

The Curiosity results were published in Science Express.

Source: NASA

About the Author
David Szondy David Szondy is a freelance writer based in Monroe, Washington. An award-winning playwright, he has contributed to Charged and iQ magazine and is the author of the website Tales of Future Past.   All articles by David Szondy

There have been two other missions, including this one by the ESA, that have detected far higher amounts of methane in the Martian atmosphere than was detected in this experiment:

I think a more likely explanation for such an incredibly low result, on a world with known geologic activity that should be producing some methane, in contradiction to earlier experiments, is that the detector is broken.

24th September, 2013 @ 06:53 am PDT

I'm surprised the bookies haven't gotten in on this one.

24th September, 2013 @ 06:56 am PDT

So how can they check that the instrument(s) has/have not failed?

It seems rather odd that previous forms of observation have indicated that there is methane on Mars yet Curiosity seems to see absolutely none at all, even when some was expected.

24th September, 2013 @ 07:47 am PDT

I think the detector is borked...

See here:

24th September, 2013 @ 10:47 am PDT

Who is to say that the form of life on another planet must involve Methane? Is this a universal constant throughout the galaxy?

24th September, 2013 @ 01:00 pm PDT

"Despite this setback, it doesn't mean that the search for life is over." Sadly, junk science will continue! A little set back will not deter the faithful in their quest to discredit the true origin of life.

24th September, 2013 @ 01:14 pm PDT

There doesn't have to be any current life on Mars. There may be fossilized evidence of life from prior epoch's. We really won't know much about it until we get there and stay and have scientists there permanently.

Which would be better a lot sooner than later.

Jerry Odom
24th September, 2013 @ 07:57 pm PDT

"Sadly, junk science will continue! A little set back will not deter the faithful in their quest to discredit the true origin of life."

I don't get it. If you're talking about religion, I still don't even understand what finding life on other planets has to do with discrediting anything. Finding microbes on Mars would be essentially the same as finding bacteria on an island here on Earth previously thought to be barren. There's life all around us. Some of it is even intelligent. That doesn't discredit God, or contradict the idea that he created life, unless you believe that Mars is beyond his reach or something.

25th September, 2013 @ 11:19 am PDT

Have to agree with Desann. It does not in any way discredit God. Read your Genisis a bit more. "In the beginning God created the heavens and the earth. The earth was formless and void, and darkness was over the surface of the deep". It is the heavens and the earth not just the third rock from the sun. And personally I find it amazing that when you look at the skies or the images of Hubble and other than any one can not see the wonder in it. Some just see rocks and stars while other see beauty and wonder. I choose the later myself.

If God was not involved it was a hell of a good accidental mix ;-] Then I look at the platypus and wonder if God was either hung over bored or just wanted to mess with people.....

25th September, 2013 @ 04:59 pm PDT

The article spoke of the quest to find life or the proof of any life at any time on Mars. Some believe that this was where life originated. How life got from Mars to the earth takes a HUGE leap of faith. The earth is the only planet where all the right ingredients and elements in their proper arrangements exist where life can be supported. To search for physical life outside of the earths realm takes a lot of what is called blind credulity.

25th September, 2013 @ 10:25 pm PDT
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