Analysis of the samples collected by Curiosity rover has revealed that Mars has nitrogen, in a form which can be used by living organisms. Nitrogen is an essential element for life forms and is used in the building blocks of larger molecules like DNA and RNA. However, the nitrogen found on Mars does not indicate the presence of life on the planet. The research team suggests that the nitrates which have been discovered are ancient and probably formed due to non-biological processes like meteorite impacts and lightning in the distant past.
However, some of the ancient features like dry riverbeds and minerals support the theory that Mars once had the conditions which support life. Such evidences have been found especially at the Gale crater which was possibly habitable billions of years ago. Jennifer Stern of NASA’s Goddard Space Flight Center said “Finding a biochemically accessible form of nitrogen is more support for the ancient Martian environment at Gale Crater being habitable.”
The Rocknest sample which helped to discover nitrogen is a combination of dust blown from distant regions on Mars and suggests that nitrates are widespread across the planet. Other evidences which suggest that the Red Planet was probably habitable once include fresh water, potential energy sources to drive metabolism in simple organisms and key chemical elements required by life like carbon.