NASA’s Curiosity rover confirms that organic molecules are present and native to Mars. Curiosity, exploring a former-lake known as Gale crater, has detected organic molecules from soil samples using its Sample Analysis at Mars (SAM) instrument.
[caption id="attachment_109" align="alignleft" width="354"] Sniffing out organics. Curiosity trundles along Gale crater. Image Credit: NASA/JPL-Caltech/MSSS.[/caption]
Organic molecules, which contain Carbon and Hydrogen atoms, were discovered trapped in mudstone which was sampled by Curiosity in Gale crater. Methane, which has been detected in the Martian atmosphere before, and chlorine-containing compound, chlorobenzene, were discovered trapped in the Martian soil.
This discovery partially confirms the evidence of chlorinated hydrocarbons on Mars obtained by the Viking landers in 1976. At the time, it could not be ruled out that the instrument on board was not accidentally creating the compounds when soil samples were baked by intense heat. Curiosity’s SAM instrument is prey to the same folly, however experiments on Earth in tandem suggest that chlorinated organic compounds are indeed present in the Martian soil.
Life on Mars
Organic molecules, from their name alone, are building blocks of life itself. Some bacteria “exhale” methane, and it may be possible (if a bit of a longshot) that past life on Mars created these compounds which got trapped in the rock. Gale crater was once a water lake and NASA’s Caroline Freissinet thinks that life there was not such a far-fetched idea, "We think life began on Earth around 3.8 billion years ago, and our result shows that places on Mars had the same conditions at that time – liquid water, a warm environment, and organic matter. So if life emerged on Earth in these conditions, why not on Mars as well?"
Non-biological possibilities accounting for the presence of organic molecules include comet impacts, meteorite dust, and geological activity. The SAM team cannot, from their findings, confirm how these organic molecules came to be on the surface of Mars, but state their next step is to determine the origin of these compounds.