The latest discovery by the Mars Curiosity Rover, Sample Analysis at Mars (SAM), was that large amounts of nitrate in soil and rocks samples were determined. These samples were taken from three different locations that were near the landing site of the rover and all of them had fixed nitrogen.
However, this discovery does not necessarily mean that it is evidence of Martian life. Nitrogen-nitrogen bonds of elemental nitrogen that actually exists as diatomic molecules could also be broken down by lightning, asteroid or comet impacts on the planet. It is believed that large amounts of fixed nitrogen could have been formed more than 3 billion years ago, during the period known as Late Heavy Bombardment. However, it could also be formed today. To support this statement, large amounts of nitrogen oxide (NO) are being detected in the atmosphere of Mars by Europe’s Mars Express orbiter. NO could also be a proposed as precursor of nitrate as well.
The Curiosity Rover is yet to answer countless questions or raise even more. We will keep you posted!
CHM 1046: Valentina d'Empaire, Victoria Lella, Andy Chavez