December 19, 2014
NASA’s Mars rover Curiosity found organic chemicals in a Martian rock which researchers named “Cumberland”. These chemicals are life’s building blocks, but we are still far from finding proof there was ever life on Mars.
Hole in the rock named Cumberland where Curiosity rover found organic chemicals. Credit: NASA/JPL-Caltech/MSSS
By drilling into Martian surface in the Gale Crater, Curiosity retrieved powder from the rock named Cumberland and in it, it found traces of organic chemicals. In the past, there were similar findings of organic chemicals which turned out to be brought from Earth along with the Curiosity. This time, however, after months of extensive analysis, researches are positive that these chemicals have either formed on Mars or originated from meteorites hitting the Martian surface.
This finding does not mean that there is or ever was life on Mars. Yes, it strongly suggests that in the past, there were conditions for some form of life, but at this point researchers take this finding for exactly what it is - a step forward in understanding the chemically active Martian surface.
"This first confirmation of organic carbon in a rock on Mars holds much promise," said scientist Roger Summons of the Massachusetts Institute of Technology in Cambridge, USA. "Organics are important because they can tell us about the chemical pathways by which they were formed and preserved. In turn, this is informative about Earth-Mars differences and whether or not particular environments represented by Gale Crater sedimentary rocks were more or less favorable for accumulation of organic materials. The challenge now is to find other rocks on Mount Sharp that might have different and more extensive inventories of organic compounds."
There is a catch however - Curiosity’s Sample Analysis on Mars (SAM) lab is like a little oven which cooks samples and analyzes produced gas. Problem with Martian rocks, Cumberland included, is that they contain chemical called perchlorate. This chlorine-containing chemical alters the structures of organic chemicals, making the findings in this case uncertain. Nevertheless, researchers are positive that chemicals found in Cumberland are in fact organic and Martian. They certainly contain carbon which is always found in organic chemicals and possibly hydrogen, also usually found in life’s building blocks.
Curiosity’s SAM also detected tenfold spikes in methane. On Earth, methane gas is produced by many organisms, but on Mars, it could also be a product of non-biological processes.
An illustration of possible sources and sinks of methane in Martian atmosphere. Credit: NASA/JPL-Caltech/SAM-GSFC/Univ. of Michigan
"This temporary increase in methane - sharply up and then back down - tells us there must be some relatively localized source," said Sushil Atreya of the University of Michigan, Ann Arbor, USA. "There are many possible sources, biological or non-biological, such as interaction of water and rock."
SAM was measuring methane in Martian atmosphere during the period of 20 months, usually finding 0.7 parts per billion. In two months in late 2013 and early 2014 it detected 7 parts per billion, supporting the suggestion that there is a localized source, whether biological or non-biological.