Over the last eight years , NASA ’s Curiosity has been exploring Gale Crater , which was once a vast lake on the surface of Mars . The rover ’s work has been key to expanding our understanding of what happened to this lake when the climate changed one thousand million of years ago . Now , results from one of the rover ’s experiments has provided challenging insight .
As reported inNature Astronomy , Curiosity has been running a multi - year experimentation with its Sample Analysis at Mars ( SAM ) , a chemistry lab used to psychoanalyze samples collected by the rover . The composition of those sample suggests the lake either freeze down over just before go away completely or between two warming menstruation .
“ At some point , Mars ’ surface environment must have experienced a transition from being warm and humid to being cold and dry , as it is now , but precisely when and how that occurred is still a mystery , ” lead generator Dr Heather Franz , a NASA geochemist based at NASA ’s Goddard Space Flight Center , articulate in astatement .
SAM was used to bake 13 dirt and rock sample to a temperature of 900 ° C ( 1,650 ° farad ) . This method allowed Curiosity to break carbon dioxide from the minerals and measure its weight . factor come in what we call isotope . These have the same chemical substance properties but a different turn of neutrons in the nucleus , which make them a bit more or a fleck less weighty .
Most carbon has 6 proton and 6 neutrons in its cell nucleus , lie with as Carbon-12 . The most common isotope of oxygen has 8 protons and 8 neutrons ( Oxygen-16 ) . static forms of these element are Carbon-13 and Oxygen-18 , but they are much uncommon . These were the ones of particular focus for the scientist .
Minerals in the lake formed from gas that originate in the Martian atmosphere , which at the time was mostly CO2 and denser than it is today . The gas was converted into carbonates , and by heating it up , SAM was able to free the natural gas back again . Surprisingly , there were a band more wakeful oxygen isotope in the minerals compare to the ambience .
This puzzling result could be explain if the carbonate formed in a freezing lake . Under those condition , the ice would have give suck up the heavier oxygen atom , leave behind the calorie-free ones to constitute the minerals studied by Curiosity . The body of work also advise that the ancient Martian atmosphere might not have been as thick aspreviously thoughtat more or less half of Earth ’s strain pressure at sea floor today .
