Mars’ surface contains a form of nitrogen required for building biological molecules such as DNA and proteins. In samples of fine-grained deposits and drilled mudstone, the Mars rover Curiosity discovered “fixed” nitrogen – a chemical form in which the ultrastrong bond in nitrogen gas, or N2, has broken. Researchers report the finding March 23 in the Proceedings of the National Academy of Sciences.
On Earth, fixed nitrogen comes from atmospheric nitrogen primarily with the help of enzymes (or industrial processes). The researchers think volcanic lightning or the heat of ancient impacts on Mars’ surface were responsible for nitrogen fixation on the Red Planet.
If life ever existed on Mars, it could have used the fixed nitrogen for building its own molecules, the researchers say.