NASA’s Curiosity Rover Discovers Evidence of Nitrogen on Mars
While studying recent samples obtained by NASA rover Curiosity, scientists discovered evidence of nitrates that serves as further potential evidence that Mars once housed an environment suitable for life. Although the landscape of Mars—dubbed the “Red Planet”—is sparse and dry, the nitrates suggest previous life on Mars, since nitrogen compounds are an essential source of nutrients for living things here on planet Earth.
In their initial pursuits, scientists studying Mars have been seeking organic carbon, which can be used and produced by living things. Nonetheless, the discovery of nitrates is also huge news according to Jennifer Stern, a planetary geochemist at NASA Goddard Space Flight Center in Greenbelt, Maryland, and a science team member for the Mars Science Laboratory mission (the formal name for Curiosity’s mission). “People want to follow the carbon, but in many ways nitrogen is just as important a nutrient for life,” she explains. “Life runs on nitrogen as much as it runs on carbon.”
The findings were published in the journal Proceedings of the National Academy of Sciences, which details how scientists examined the data from several samples obtained by the SAM (Sample Analysis at Mars) instrument at three different spots near Curiosity’s landing site. Curiosity’s primary mission was to drive to a 3-mile-high mound in the middle of Mars’ Gale Crater, but during a detour the amazing NASA rover was able to obtain the evidence of nitrates.
Scientists examined the resulting gases from the rock samples by cooking them in SAM’s oven, a process that bore an ample amount of nitric oxide that was presumably derived from nitrates. “What we’re detecting is nitric oxide, but we know from lab experiments that when we heat up nitrates, they break down in a predictable way,” said Stern. “And that’s why we think these are nitrates.” The scientists verified it was not a false sample by subtracting out the amount of contamination due to the rover itself, so the evidence of nitrates in Martian rock is fully confirmed.
A specific area of the research that excited scientists was that the amount of nitrogen left over—approximately 110 to 300 parts per million of nitrate in the Rocknest sample, 70 to 260 parts per million in John Klein, and 330 to 1,100 parts per million in Cumberland—were comparable to very dry places on Earth, like South America’s Atacama Desert.
While the majority of nitrates on Earth are produced by living things, scientists attribute the presence of nitrates on Mars to a “thermal shock,” such as an asteroid impact or lightning strike. The scientists’ next area of work will be to determine the precise process for what is generating the nitrates, in addition to whether or not that process is currently occurring. “We’re going to try to understand whether this process is still happening today at all,” Stern explains, “or whether this all happened in the past in a different Mars, in a different climate regime, in a different atmosphere.”
While it’s still unknown if living things have ever used Mars as their habitat, the evidence of nitrates discovered by Curiosity is in addition to mounting evidence that the Red Planet once supported life. Future studies will hopefully dig deeper into Mars’ past, which becomes increasingly fascinating with each newly released study on possible life on Mars.