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(Music)

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SAM stands for the Sample Analysis at

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Mars instrument suite. It's really one of the most complex and analytical

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chemistry laboratories ever sent to the surface of the Red Planet. It's been

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miniaturized to fit right into the body of the Mars Science Laboratory

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Curiosity Rover. One of the major goals of the Mars Science Laboratory mission

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is to search for habitable environments in Gale Crater. And by by habitable

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environments, what I'm talking about are environments that could have supported life.

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(Music)

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So there are several pieces of big news that SAM has found.

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The first is the discovery of methane. Now methane has been

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found previously in the Martian atmosphere by both Earth-based telescopes

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and space-borne orbiters. But this is the first time that we've actually

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seen a sharp increase and decrease in the abundance of methane in the atmosphere

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in Gale Crater. What this really means is that present day Mars is an active

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environment. Now at this point we don't know the origin of this methane.

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It could be biological, from maybe methanogenic bacteria

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deep in the subsurface releasing methane. But there are non-biological explanations

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as well - such as water-rock interactions in the subsurface that could also

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produce the methane signals that we're seeing. The second exciting discovery

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from SAM is the detection of Martian organic compounds.

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We found several different types of organic molecules including chlorinated alkanes

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and chlorobenzene - compounds that are not common on Earth - in a mudstone

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that was deposited in an ancient lakebed environment in Gale Crater.

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This is a really exciting discovery because we've been looking for organic compounds for decades

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on the surface of Mars. And this is the first time that we've actually found

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Martian organic material in the surface. Now, at

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this point we don't have enough evidence to tell us whether or not the organics

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we're finding are biological or non-biological in origin. There are

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several viable non-biological explanations, including this organic

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material could have come down from space - from meteorites or comets. Or,

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organics can be formed by geological reactions in the rock itself.

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Now what's exciting about this discovery is it gives us new hope

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in the search for chemical evidence of life. We've found the organic material,

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now the next step is trying to figure out what its origin is.

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(Music)

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So in addition to the measurements made by SAM on Mars, we've had

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to do hundreds of laboratory experiments back on Earth to simulate

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the conditions on the surface of the Red Planet in order to convince ourselves

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that the organic material we were detecting by SAM was really Martian in origin

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and not something that we had brought with us to Mars.

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(Music)

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So although at this point in the mission we can't conclude that there was definitively life

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on Mars, the SAM discoveries have really shown us that all of the basic

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ingredients for life were there - including complex organic compounds,

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the building blocks of life. Now with the detection of organics in Gale

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Crater, the probability that Gale Crater Lake could have supported life

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goes up.

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(Beeping)

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