Nitrogen has been added to the list of potential biological ingredients of Mars through research from NASA's Curiosity rover.
In a report published this week at the National Academy of Sciences, researchers report that Curiosity found oxidized nitrogen compounds in samples taken from three sites of the Gale crater, which the rover has been studying since August 2012.
"Samples contained more nitrogen than could be brought by instruments from the Earth, while most of the nitrogen was in the form of nitrogen oxide," the scientists wrote in the summary.
The team advanced the theory that nitric oxide could be released by the decomposition of nitrates in samples that were exposed to heat.
"For terrestrial life, a certain form of nitrogen is required for the synthesis of the most important biomolecules, and the discovery of nitrogen in Martian rocks and sediments is extremely important for determining the past life potential of Mars," the researchers noted. Nitrogen is important for all known life forms, as it is the building block for larger molecules such as DNA and RNA.
"However, there is no evidence that the nitrogen molecules found by the team were formed by life forms," added NASA. "The surface of Mars is inhospitable for all known forms of life. The team from NASA believes that nitrates have an ancient past and probably originated from non-biological processes such as the fall of meteorites and lightning in the distant past of Mars."
Samples containing nitrates were collected from dust, which came here due to the wind from a place known as Rocknest, as well as samples of clay drilled in another place known as Yellowknife Bay.
Curiosity has previously found evidence of organic molecules and liquid water — ingredients that are thought to be necessary for life.
