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Life on Mars: just add carbon and stir

The building blocks of life have been discovered on Mars … in Martian meteorites that fell to Earth. Let me rephrase that: according to a paper by published in Science Express on Friday, meteorites from…

We’re a long way off finding little green men, but we might find evidence of life on Mars within a year.

The building blocks of life have been discovered on Mars … in Martian meteorites that fell to Earth.

Let me rephrase that: according to a paper by published in Science Express on Friday, meteorites from Mars have been found to contain the basic ingredients for life as we know it.

This is amazingly, mind-bogglingly awesome!

The last time a headline like this made the front pages of most of the papers was back in 1996, when evidence of organic life and “fossils” had been found in a meteorite that had fallen to Earth from Mars.

But a few years later, after a lot more research, the results fell into dispute. In the words of American astronomer Carl Sagan, “extraordinary claims require extraordinary evidence” and the evidence wasn’t quite enough to convince all the scientists doing research on the evolution of life on Earth (or Mars).

Now some commentators are saying that the new data, published by a team of international researchers, proves the 1996 meteorite didn’t contain evidence of life. Others say that it proves that life could have existed on Mars in the past.

The Martian surface doesn’t look all that hospitable, but it could contain life. NASA (Viking 1, February 1978)

So, who is right? Does this new data mean there is life on Mars today? Have they proved that life existed on Mars in the past?

No, and no. What has been found is that many samples of Martian rock contain carbon that has not been made by life. But this new research means there is a better chance of life having evolved on Mars.

Some time later this year, or early next, you may be reading a newspaper headline stating life has been found on Mars. This will also be awesome!

Headlines such as these would come from the results of a new Mars rover named “Curiosity” – a scientific laboratory on wheels, which will land on Mars on August 5.

Its task is to take samples of Martian rocks and look for evidence of past life. It won’t be looking for fossils or skeletons (although if it found them you’d hear champagne corks popping all over Earth). Curiosity will be looking for the chemical signatures of organic life in the form of particular types of carbon compounds.

To make life as we know it (on Earth), you need carbon – preferably in the form of “reduced” carbon compounds. The Science Express paper tells us how these have now been found in a number of meteorites from Mars.

NASA’s Curiosity rover touches down in August and will resume the search for life on Mars. NASA

So what’s so interesting about carbon? Carbon is the stuff that diamonds are made of, but not all carbon makes gemstones. Some of it makes up graphite (the “lead” in pencils), while other arrangements of carbon atoms make up buckyballs and nanotubes – the toys of nanotechnology.

Life on Earth isn’t made up of any of these forms of carbon: it’s composed of “organic” carbon – long chains of carbon atoms joined to other elements such as oxygen, hydrogen and nitrogen.

The oldest forms of organic carbon we’ve found on Earth are “reduced” carbon chains trapped in rocks that would have formed in ideal conditions for life to survive. And once these are around, any living organisms can use them to make more of themselves.

There’s a chance we could find life on Mars within a year … if it’s there. NASA

And it is these types of reduced carbon that have now been found in meteorites from Mars.

Is this exciting? Hell, yeah! It means you’ve got the ingredients for potential life in rocks from another planet. It means that Curiosity has a much better chance of finding what it is looking for.

But, there is one major drawback about these new findings.

As mentioned, the carbon found in these meteorites was not made by living things – it was made through natural chemical reactions that do not involve life.

This means that when we look at the results coming from Curiosity later this year, we will have to take a lot more care to make sure the types of carbon found contain the signatures (isotopic fingerprints) of having been made by life. Fortunately, that is well within the capability of Curiosity’s mobile laboratory.

So, put the champagne on ice – the search for life on Mars is about to get interesting.

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9 Comments sorted by

  1. Ron Chinchen
    Ron Chinchen is a Friend of The Conversation.

    Retired (ex Probation and Parole Officer)

    Seems a bit of carbon, mixed with hygogen, a smattering of oxygen and a soup primarily of water and you have the ingredients for life anywhere in the Universe. I suspect that life is one of the easiest structures (given the right temperature range, minerals, time etc) to create and the fundamental ingredients are so common that even the frozen scarred and radiation exposed asteroids and comets are probably nurseries for life waiting for the opportunity to spawn in comfortable environments.


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  2. Norm Stone


    "Sometimes I think we're alone. Sometimes I think we're not. In either case, the thought is staggering." 
           -- R. Buckminster Fuller

  3. Tim J Hawes


    Amazing stuff. I wish I was in this field sometimes.

    I hope there is life on Mars. We need to make them pay for polluting Earth with all that life giving carbon. When will Julia legislate a Mars Carbon Tax?

    1. Emma Anderson

      Artist and Science Junkie

      In reply to Tim J Hawes

      You're silly, Mr. Hawes.

      In that vein, let me propose a story.

      Many millions of years ago the building blocks of life spontenously evolved from chemical elements on Mars and a chunk of Mars flew to Earth. From that time on the two branches of life in this part of the solar system had different fates. The Earthlings were a bit slow to evolve, but the Martians grew quickly. Eventually there were people like creatures that invented robotics, and wanted to find life on earth, but didn't. But…

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    2. Norm Stone


      In reply to Emma Anderson

      You're on the money ($2.4B I think) here Emma. Mars, La la land, it's all the same ..... still fekin awesome tho

    3. Emma Anderson

      Artist and Science Junkie

      In reply to Norm Stone

      In all seriousness if they do find nanotech on Mars I will be so fekin stoked. Little blue men would be a happy coincidence. Maybe I should become a snake oil saleswoman, due to the awesomeness of said prophecy.

      Yeah and we don't wanna go the way of Mars. They're dead. We're not.

      The End.

    4. Norm Stone


      In reply to Emma Anderson

      Just a minute they're not blue the're green. Does this have implications for Bob B?

    5. Emma Anderson

      Artist and Science Junkie

      In reply to Ron Chinchen

      Nah, that's just silt, from hanging around the crevasses for so long. Underneath they're blue. I did a science no no, I forgot the methods section

      1. Find weird metal
      2. Clean off red stuff
      3. Oooh shiny
      4. Hack
      5. ???
      6. If you don't know what that song was a parody of I will be very surprised