alh84001

Organics Found in Mars Meteorites, But Nothing Biological

Article Updated: 23 Dec , 2015

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Editor’s note: This guest post was written by Andy Tomaswick, an electrical engineer who follows space science and technology.

The search for biologically created organic molecules on Mars goes back at least to the 1970s with the Viking program. Those missions had famously mixed results, and so the search for carbon-based life on Mars continues to this day. Researchers keeping piling on more and more evidence to excite astrobiologists and new results published in a study by the Planetary Science Institute and the Carnegie Institute of Washington may heighten their enthusiasm.

The latest results come from a team led by Andrew Steele of the Carnegie Institution for Science who surveyed meteorites from Mars, which covered a 4.2 billion year time span of Martian geology. While it is no surprise that there are organics on Mars — that Martian meteorites contain carbon-based molecules has been known for years — the team confirmed those findings by detecting organics on ten of the eleven meteorites they examined. However, questions remained as to where exactly the meteorite-bound organic molecules came from and, if they were from Mars, what had created them?

The team set out to answer these questions and came to the conclusion that the molecules are indeed from Mars and not the result of some cross-contamination from Earth’s biosphere. However, they also found that the molecules were not created by any biological process. The organics actually formed in the chunks of rock that later became the meteorites that transported them to earth. Their formation was part of a volcanic process that traps carbon in crystal structures formed by cooling magma. Through a series of non-biological chemical reactions, the complex organics found in the meteorites are created using the carbon trapped in these crystals.

The team also casts doubt on another possible explanation: whether the organics might be caused by emissions from microbes that had migrated into the volcano via tectonic processes similar to those on Earth. They point out that Mars does not have the tectonic activity similar to Earth so there is very little likelihood that the molecules are created by microbial activity.

That might sound like a depressing result for the astrobiologists. But the important finding from this study is that Mars has been natively and naturally creating complex organic molecules for 4.2 billion years and may be still be doing so today. Since the creation of organic molecules on Earth was a precursor to life, scientists can still hold out hope that the same life-creating process might have already happened on the red planet.

Interestingly, one of the Martian meteorites that was studied was the famous ALH84001, the meteorite that some researchers claimed in 1996 might contain fossils from Mars. That claim was subsequently strongly challenged, and studies of the rock are ongoing. ALH84001 is a portion of a meteorite that was dislodged from Mars by a huge impact about 16 million years ago and that fell to Earth in Antarctica approximately 13,000 years ago. The meteorite was found in Allan Hills ice field in Antarctica.

Read the team’s abstract.

Lead image caption: ALH84001 is one of 10 rocks from Mars in which researchers have found organic carbon compounds that originated on Mars without involvement of life. Credit: NASA/JSC/Stanford University

Sources: Planetary Science Institute, LiveScience, NASA

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SnyderJacob
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SnyderJacob
June 20, 2012 7:32 PM

m y frien d’s m oth er-i n-la w ma kes $8 5 eve ry h o ur o n th e co mputer. S h e h as be e n o u t o f a jo b for 6 m ont hs b ut l ast mo nth h er p aych eck w as $ 1 91 77 j ust wo rking on the c omp ute r fo r a fe w h our s. R ea d m or e h er e

?????? (C li ck O n My N am e F or L i n k)
0

Kawarthajon
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Kawarthajon
June 20, 2012 8:00 PM

Methane caused by geological processes, organic chemicals in meteorites caused by geological processes … the case for life on Mars isn’t looking up these days! sad

Torbjorn Larsson OM
Member
Torbjorn Larsson OM
June 20, 2012 10:07 PM

Don’t forget that the recent signs of water including sediments can be the result of brief periods of snowmelt as Mars axis wanders chaotically. This means that there have been such surface habitable periods interspersed with massive sterile ones, and that perhaps the only large scale habitable period was before the large heavy bombardment.

On the other hand that early period seems to have been very habitable as per recent finds, and the crust should have been a nice refugia for life afterwards. In any case, extinct or extant life, we may find some.

Kawarthajon
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Kawarthajon
June 21, 2012 2:41 PM

How long was that early period of habitability? How would we find life on Mars if it is buried deep underground? Would there be fossilized evidence of simple life on the surface of Mars?

Torbjorn Larsson OM
Member
Torbjorn Larsson OM
June 23, 2012 1:01 AM

– I think the existence and length of the habitable period is debated, but up to the Late Heavy Bombardment has been mentioned in the NASA meeting on Mars exploration that was web published this week.

But as on Earth, we should likely expect extant monocellular life to survive in the crust, because in simple models it proliferates faster than any reasonable rate of impactors can sterilize. However, that result seems not much spread or even accepted as of yet.

– The two last questions I already described in a lengthy reply to Dampe above.

Bobr
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Bobr
June 21, 2012 6:45 PM

I disagree – I think its stock goes up almost daily!
This interesting release just came out: http://carnegiescience.edu/news/extensive_water_mar%E2%80%99s_interior
All the ingredients are there. We just have to find the cake!
…or make our own.

Torbjorn Larsson OM
Member
Torbjorn Larsson OM
June 23, 2012 1:11 AM
Good catch! I have commented elsewhere but should repeat: The abstract (IIRC today) goes on to show how the initial water content was 10 times larger, meaning Mars and Earth-Moon terrestrials place on ~ 0.5 % of water. 5 times less water and Earth may not have plate tectonics (it is marginal in size for that), 5 times more and we may not have continents. This has worried me re exoplanet habitability. Note that this is relatively dry, since most asteroids, pristine chondrites, have 15-20 % of water. But now it seems like a generic result of how terrestrials aggregate. It also predicts how that water/hydrogen is internal but enough to explain Earth’s oceans by volcanism. No later… Read more »
Aqua4U
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June 20, 2012 8:17 PM

Well… at the very least, it is reassuring to note that there IS a source of carbon available for possible life?

Andy Tomaswick
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June 21, 2012 2:04 AM

I think that’s what the researchers wanted to get across: that carbon is being formed on Mars and carbon is a prerequisite to the formation of life as we know it. To me, the more carbon there is on a planet the better, as that means more of a chance for that one magical spark to happen at some point.

Torbjorn Larsson OM
Member
Torbjorn Larsson OM
June 20, 2012 9:55 PM
Of course there are carbon on Mars, the atmosphere is carbon dioxide and martian meteorites like ALH84001 with their carbonates confirm there is or was a carbon cycle with the crust. The question is if the PAH (polyaromatic hydrocarbons) were produced only in the meteorites, say at impact, as asteroids and comets also contain them. Far easier to accept that Mars contributed to the PAH assembly. But with only the abstract available outside the paywall I don’t know what they mean with “tectonic activity similar to Earth”. Mars has geologically recent volcanoes, signs of geologically recent magma in the meteorites and even signs of _historical_ landshakes. One mechanism isn’t threatened by having alternatives, nor is it strengthened by… Read more »
Andy Tomaswick
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June 21, 2012 2:02 AM

Strangely, in the press release itself it didn’t mention much about the tectonic activity hypothesis. That was mentioned in the LiveScience article quoted at the end of the story. It also brought up the question in my mind of whether this process is still going on, as I’ve always though Mars was a dead planet geologically. Are there even any active volcanoes on Mars anymore?

Torbjorn Larsson OM
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Torbjorn Larsson OM
June 21, 2012 12:23 PM
No, the question is Mars has a convective core and hence can maintain active volcanoes is still an open question. I’m pulling this from memory, so YMMV: – The differently aged shergottites, martian meteorites like ALH 84001, shows a sustained magmatic source all through martian history from ~ 4.2 billion years ago to some ~ 160 million years ago. – The large volcanes have been crater dated to having lava flows to ~ 100 million years ago. I think. – And recently they discovered rock falls from landshakes that are ~ 100 000 years old. As I remember it. So there is a definitive sustained heat source, and it would be unlikely to have ended at the time… Read more »
Dampe
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Dampe
June 21, 2012 1:45 AM

While I appreciate the science of going to Mars (I love the red planet) I really would love for their efforts to be spent on other moons of Saturn and Jupiter. We’ve gone to Mars for 40 years and have found very little supporting evidence. Unless Curiosity finds something, that must certainly be a stamp for Mars not supporting life. Sorry if that sounds cynical, but It saddens me to see the other worlds of the Solar System ignored.

Andy Tomaswick
Guest
June 21, 2012 2:07 AM
I agree wholeheartedly. I think the problem is two fold for the missions that you’re probably thinking about. 1) It’s alot harder to look the farther out you get in the solar system. Compared to dropping a lander/rover or two on a planet where we’ve already done it seems easy by comparison. 2) The time span it takes to get to some of the interesting moons is alot longer than even a mission to Mars, which makes it a little harder to convince the public that it’s worth it. I have a feeling that we’re going to start pushing that boundary soon though, especially if the price of getting to orbit drops as much as it could using… Read more »
Lawrence B. Crowell
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Lawrence B. Crowell
June 21, 2012 5:12 PM

The best option is for the next mission to Saturn to include a fly through of the Enceladus geyser plumes. The probe capsule which flies through this then makes a return trip to Earth. If these Jovian and Saturnian moons with subsurface oceans harbor life this seems to be the cheapest and simplest way to put it to the test.
LC

Torbjorn Larsson OM
Member
Torbjorn Larsson OM
June 21, 2012 12:41 PM
We have two efforts here, the public wants to know if there is or was life, and the science trying to establish it. The Vikings were based on the premise “let us look for current life best we can – oh, and water too”. And it failed, miserably. – The biological experiments were so bad you can just about predict their results by adding Phoenix data on perchlorates 40 years later. – They missed digging to the underlying ice that Phoenix confirmed with about 20 – 50 cm according to current modeling of the orbiter data. After that, the scientists buckled down to systematically (as in “science” =D) establish current and previous habitability to see if you should… Read more »
Hans Peter Uhrig
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Hans Peter Uhrig
June 21, 2012 1:43 PM
“The biological experiments were so bad you can just about predict their results by adding Phoenix data on perchlorates 40 years later.” What was so bad about them? Do you question the credibility/integrity of great scientists like Vance Oyama (NASA Ames) or Norman Horrowitz (Caltech) who designed the experiments? Levins method for the LR – radio respiration for detection of microbial metabolism (which was invented by him) is commonly used on Earth as well like in the following example of use in extreme environments not unlike Mars: http://www.ncbi.nlm.nih.gov/pubmed/17942178 But seriously what specific results of the BIOLOGY experiments could have been predicted by perchlorate? Perchlorate actually seems to have spoiled the GC/MS (none-)detection of organics which was the main… Read more »
Torbjorn Larsson OM
Member
Torbjorn Larsson OM
June 23, 2012 12:50 AM
– The series of experiments failed because they were inconclusive. That result was easy to predict beforehand. They wanted to detect heterothrophs which needs a fairly large ecosystem with autothrophs in the bottom. So you need to detect organics too, which the heterothrophs should live of. If they didn’t detect the latter, the whole series of experiment would be inconclusive, and could even be contradictory. That is what happened. Heterothrophs are the result of a long evolution and complex ecologies, so I think it was a stretch to look for them in the first place. More likely it seemed to be an “easy and conclusive” experiment to the mission. – The perchlorates explains why you can’t detect organics… Read more »
Hans Peter Uhrig
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Hans Peter Uhrig
June 25, 2012 8:35 AM
Are you sure you understand the full approach of Viking? Your statement “They wanted to detect heterothrophs” is wrong! All three biology experiments aimed for different kinds of life: PR (most tests positive for life by missions protocols): photosynthetic life (as a base for other life?) LR (ALL tests strong positive for life by mission protocols): more or less the other way around – heterotrophs GEx (very strong mixed activity – inconclusive/negative by mission protocols): generic life which alters the composition of the surrounding atmosphere Again all experiments had strong activity in the soil which still can not be fully explained by inorganic chemistry alone. Honestly, these results – at the very very least – would scream for… Read more »
Hans Peter Uhrig
Guest
Hans Peter Uhrig
June 25, 2012 8:36 AM
Are you sure you understand the full approach of Viking? Your statement “They wanted to detect heterothrophs” is wrong! All three biology experiments aimed for different kinds of life: PR (most tests positive for life by missions protocols): photosynthetic life (as a base for other life?) LR (ALL tests strong positive for life by mission protocols): more or less the other way around – heterotrophs GEx (very strong mixed activity – inconclusive/negative by mission protocols): generic life which alters the composition of the surrounding atmosphere Again all experiments had strong activity in the soil which still can not be fully explained by inorganic chemistry alone. Honestly, these results – at the very very least – would scream for… Read more »
IVAN3MAN_AT_LARGE
Member
IVAN3MAN_AT_LARGE
June 25, 2012 1:05 PM

Actually the longer i studied Viking the more angry i was getting…

Well, dude, that’s your problem – you’re letting your emotions (double posting is one indication of that) cloud your logical judgement!

Hans Peter Uhrig
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Hans Peter Uhrig
June 25, 2012 1:36 PM
Yes, sorry for the double posting. Was more of a technical glitch than emotions but never mind: don’t worry about my logical judgement – the emotions are long gone (studied the Viking mission for a long time already) and I look forward to the flight data of that odd uncurious-curiosity rover with some neat contamination issues This is what ESA scientists thinks about the Viking mission results: “Numerous attempts have been made in the laboratory to simulate the reactions observed by the Viking biological package. While some have reproduced certain aspects of the data, none has succeeded entirely. Incredibly, almost 30 years after Viking, the crucial chemical oxidant hypothesis remains still untested.” http://www.esa.int/SPECIALS/ExoMars/SEMK39JJX7F_0.html @Mr. Larsson: Not the Viking… Read more »
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