It’s been an amazing week for detection and study of water in our Solar system. Just last week we received the first results of the Rosetta mission’s analysis of water from comet 67P. Now we’ve received the latest breakthrough from the Curiosity Rover on Mars, results on Water, Methane, and even Organic material!
The Sample Analysis at Mars instrument (SAM) took measurements of the Martian atmosphere over a period of 20 months, and for two of these months in late 2013 and early 2014, the Methane levels were 10 times as high as measurements before and after the spike.
“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, and Curiosity rover science team. “There are many possible sources, biological or non-biological, such as interaction of water and rock.”
Drilling into a rock dubbed ‘Cumberland’ on May 19th, 2013, the dust sample was transferred to the SAM instrument. Analysis of this sample indicated water, and the first definitive detection of organic molecules below the surface. The organics could have formed on Mars, or they could have been deposited by ancient meteorites.
Organic molecules, which contain Carbon and Hydrogen, are the building blocks of life. However, finding these molecules on Mars does not definitively prove Mars has or once had life, rather that Mars is currently chemically active and there were favourable conditions for life on ancient Mars.
SAM also analysed a sample of water molecules bound into minerals in the rock Billions of years ago. By looking at the ratio of Deuterium (A hydrogen atom with a proton and a Neutron) to normal Hydrogen, scientists were able to compare the past Martian water from when the Cumberland rock formed to current water vapour in the atmosphere. This is because Deuterium water is heavier and is less likely to be lost into Space, while lighter water can be liberated from the upper atmosphere more readily.
The ratio in the Cumberland rock is about half the current ratio in the atmosphere, suggesting that much of the Martian water loss has occurred since the rock formed. However, the D/H ratio in the water is still 3 times as high as the original ratio on Mars, suggesting that a large amount of Martian water was lost before the rock formed. The original ratio on Mars is assumed to be the same as the current D/H ratio of Earth’s oceans.
The results are arguably the most significant from the Curiosity rover thus far. As the rover moves further on its journey to the summit of mount sharp, the data from each successive rock layer should reveal the geological history of Mars, giving us insights into if and when Mars could have harboured life.