Could There Be Organic Matter on Mars?

Nov 17, 2014

Credit: Bastian Baecker (University of Heidelberg and Max Planck Institute for Chemistry) and Luigi Folco (University of Pisa)

By Tanya Lewis

The origins of organic matter found by Mars lander missions have long been debated, but a new study suggests a way to find out whether these chemicals of life came from the Red Planet or elsewhere.

Several Mars lander missions have detected chloromethane, a chemical sometimes produced by living organisms, but most scientists think the findings were contamination from Earth.

Now, a team of researchers has replicated these experiments on a meteorite found on Earth, and found that it produced chloromethane from organic materials contained in the space rock. The findings suggest the chloromethane on Mars may have come from meteorite debris on the planet’s surface or the Martian soil itself, rather than from Earth.

NASA’s Viking landers descended onto the Red Planet in 1976. The Viking 1 lander, the first of the two, detected chloromethane in a sample of soil it baked in a small oven on board. The second lander, Viking 2, did not detect chloromethane, but did find traces of dichloromethane, another organic compound. However, scientists dismissed the findings, saying they were contamination from Earth.


 

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10 comments on “Could There Be Organic Matter on Mars?

  • The second lander, Viking 2, did not detect chloromethane, but did find traces of dichloromethane, another organic compound. However, scientists dismissed the findings, saying they were contamination from Earth.

    There are meteorites of Martian material, on Earth which originated from crater impacts on Mars, so it is highly probable that meteorites from impacts on Earth, have landed on Mars.

    There is certainly methane around in the solar-System as Cassini and the Huygens probe landing on Titan showed.
    http://www.planetary.org/blogs/emily-lakdawalla/2014/0315-titans-lakes-the-basics.html
    Methane is made of one carbon atom bonded to four hydrogen atoms. At Titan’s distance from the Sun, solar ultraviolet radiation destroys methane rapidly, breaking it into bits — loose hydrogen atoms, and carbons bonded to a couple hydrogens. When these molecule pieces come back together, they don’t always rearrange into methane. Carbons stick together, making bigger molecules with more carbons. Then those get broken up, and even bigger pieces stick together. Sometimes they combine with nitrogen from the atmosphere. This is more or less the same process that makes smog on Earth, and is one reason it’s so hard to see through Titan’s atmosphere. Some of the loose hydrogens combine into molecular hydrogen gas. Physics says the lightweight hydrogen gas should escape Titan entirely. This all happens pretty rapidly; methane is just not stable at Titan, not over the age of the solar system.

    So how is there methane still around for us to see it? One possibility is that it’s just a freak sudden event that released a bunch of methane into Titan’s atmosphere at the moment in the solar system’s four-billion-year history that we happened to develop the tools to be able to detect methane on Titan. That’s possible, but relatively unlikely. Or, there’s a reservoir of methane at the surface or inside Titan that resupplies the atmosphere. At one point, we thought Titan might be covered in a global ocean of methane. ESA even designed the Huygens lander to float, just in case it landed in a methane ocean; we really didn’t know what we’d find down there when we launched Cassini in 1997

    We can’t simply assume that because methane, or compounds of methane are present, that indicates life.



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  • The statement that because there are meteorite fragments on earth that originated from Mars then the opposite is likely, surely the forces needed to propel fragments from Earth to Mars would be far greater due to our stronger force of gravity. Would this not reduce the likelihood of transfer of matter from Earth to Mars?



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  • Ken Nov 18, 2014 at 10:36 am

    The statement that because there are meteorite fragments on earth that originated from Mars then the opposite is likely, surely the forces needed to propel fragments from Earth to Mars would be far greater due to our stronger force of gravity. Would this not reduce the likelihood of transfer of matter from Earth to Mars?

    Mars’ escape velocity (5.0km/sec) is a little less than half of that of Earth (11.2km/sec) and Earth also has a much thicker atmosphere.

    However, the force of meteor impacts such as the KT impact, is such that material would still be thrown into orbit or beyond.



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  • I agree, I’ve always thought it improbable that debris from meteor impacts on earth could find its way to Mars, since it requires a much greater escape velocity — for both a larger earth as well as sun. In addition, the odds are further reduced when you consider the much larger orbital path of Mars. I’m not saying that it couldn’t happen, just very unlikely.



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  • Billions and Billions Nov 18, 2014 at 1:34 pm

    I agree, I’ve always thought it improbable that debris from meteor impacts on earth could find its way to Mars, since it requires a much greater escape velocity — for both a larger earth as well as sun.

    http://www.technologyreview.com/view/425093/earth-ejecta-could-have-seeded-life-on-europa/
    Earth Ejecta Could Have Seeded Life on Europa

    This raises an interesting question: how much Earth ejecta could have ended up elsewhere in the Solar System?

    Various astronomers have studied this question by simulating how far test particles can travel after being ejected from Earth. Their conclusion is that it’s relatively easy for bits of Earth to end up on the Moon or Venus. But very little would get to Mars because it would have to overcome both the Sun and the Earth’s gravity.

    Today, Mauricio Reyes-Ruiz at the Universidad Nacional Autonoma de Mexico and a few pals reveal the results of the biggest simulation of Earth ejecta ever undertaken. And they have a surprise.

    These guys have created a computer model in which 10,242 test particles are ejected from Earth into the Solar System. They’ve run the model five times, increasing the average velocity of the ejected particles each time.

    What they’ve found is quite a surprise. First up, the number of particle that end up on Mars is two orders of magnitude greater than previous studies have found.

    But the biggie is that, at higher ejection speeds, particles are much more likely to end up hitting Jupiter than Mars.

    In addition, the odds are further reduced when you consider the much larger orbital path of Mars. I’m not saying that it couldn’t happen, just very unlikely.

    It is indeed more likely that most Earth ejecta would end up in other places.



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  • Ken Nov 18, 2014 at 10:36 am

    Would this not reduce the likelihood of transfer of matter from Earth to Mars?

    Ejecta is more likely to be flung into orbit from Mars, but it can also be ejected from Earth.

    The asteroid that wiped out the dinosaurs may have catapulted life to Mars and the moons of Jupiter, US researchers say.
    http://www.bbc.co.uk/news/science-environment-25201572

    They calculated how many Earth rocks big enough to shelter life were ejected by asteroids in the last 3.5bn years.

    The Chicxulub impact was strong enough to fire chunks of debris all the way to Europa, they write in Astrobiology.

    Thousands of potentially life-bearing rocks also made it to Mars, which may once have been habitable, they add.

    *”We find that rock capable of carrying life has likely transferred from both Earth and Mars to all of the terrestrial planets in the solar system and Jupiter,” says lead author Rachel Worth, of Penn State University.**

    But thanks to advances in computing, they are now able to simulate these journeys – and follow potential stowaways as they hitch around the Solar System.

    In this new study, researchers first estimated the number of rocks bigger than 3m ejected from Earth by major impacts.

    Three metres is the minimum they think necessary to shield microbes from the Sun’s radiation over a journey lasting up to 10 million years.

    They then mapped the likely fate of these voyagers. Many simply hung around in Earth orbit, or were slowly drawn back down.

    Others were pulled into the Sun, or sling-shotted out of the Solar System entirely.

    Yet a small but significant number made it all the way to alien worlds which might welcome life. “Enough that it matters,” Ms Worth told BBC News.



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  • Does anybody know just how much oxygen and water would be necessary for the planet to rust? I’m of the impression that free oxygen levels are pretty low without photosynthesis as a general rule



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  • Clayton Nov 22, 2014 at 3:52 pm

    Does anybody know just how much oxygen and water would be necessary for the planet to rust? I’m of the impression that free oxygen levels are pretty low without photosynthesis as a general rule.

    Solar radiation breaks water molecules apart in the upper atmosphere, with the freed hydrogen (being lighter) – being lost to space. Other large molecules can also be broken apart by radiation. Mars is smaller with weaker gravity so is less capable of holding on to an atmosphere.

    Mars certainly has water ice at present and is known to have been warmer in the past.

    Planets are not of “fixed mass”, but gain and lose material as their gravity pulls in some matter, and is too weak to hold on to some lighter atoms and molecules. They can also lose matter as ejecta from impacts.

    http://scitechdaily.com/earth-loses-50000-tonnes-of-mass-every-year/

    Photosynthesis is not necessary for free oxygen, although if there is methane in the atmosphere this will be likely to oxidise taking up free oxygen and producing CO2.

    We know the early Earth had much iron dissolved in the seas, before free oxygen rusted it to the iron ore deposits we find today.



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