Curiosity sniffs Mars, and it doesn't smell too bad!

The latest measurements from Curiosity's Sample Analysis at Mars have found that the planet's atmosphere is mostly carbon dioxide, with traces of oxygen, nitrogen and argon. NASA rover Curiosity has been working deeply on the Martian surface, trying to get a smell of any methane in the Red Planet's atmosphere. This organic compound is tied to biological processes. For example, a cow’s digestive tract uses anaerobic bacteria to break down cellulose, then the bacteria produces methane that it is later expelled as waste, thus lending a certain odor to the animal's flatulence. Scientist thought to have found methane gas on Mars using Earth-based telescopes that observed seasonal methane hotspots.

This image shows the rover scanning for traces of life in the Martian soil.

No significant amount of methane has been found, however negative results doesn't necessarily mean that the evidence book is closed. If methane occurs seasonally, Curiosity is perhaps just sniffing around at the wrong time.

NASA’s findings also support the possibility of life flourishing on Mars ages ago. Curiosity came to find that Mars had once a much abundant atmosphere; lost over millions of years ago. The Mars of the past may have had a much richer carbon dioxide atmosphere, which would have warmed it to a nice and stable temperature. If you add water to the equation, then life could have easily develop in the Red Planet.

Currently the Martian atmosphere is so thin that water would boil in a matter of seconds. This happens because the water needs pressure to remain as a liquid, and there is not enough gases in the surface of Mars to make this happen. Additionally, the temperatures are extremely low, making any trace of water to exist as ice.

Still, there is evidence supporting that water exited in the past, so the big question remains: Where is it now? There is not easy or definite answer to this question, as we don’t know what Curiosity or other expeditions may uncover in the future. For now, scientists have found frozen water beneath the surface and, as you can see in the picture below. It is mostly concentrated in the South Pole.

In this false-color map of Mars, soil enriched in hydrogen is indicated by deep blue. Source: the neutron spectrometer on board NASA's 2001 Mars Odyssey