Maybe there really was life on Mars. Scientists think a volcanic explosion or collision with a Pluto-sized planet could have wiped out an entire alien race four billion years ago.
The "catastrophic" event could have caused the air to shrink, suffocating any life forms that existed on the red planet, Guardian Express reported.
"As Mars became a planet and its magma ocean solidified, catastrophic outgassing occurred while volatiles were delivered by impact of comets and other smaller bodies," Dr. Chris Webster at NASA's Jet Propulsion Laboratory and lead author of the study said.
" Solar wind and the possible impact by a Pluto-sized body is thought to have stripped much of the initial early atmosphere from the planet, and since then the atmosphere has developed as a balance between volcanic injection and loss to space," he said.
New information from NASA's Mars Curiosity rover led researchers to believe Mars' atmosphere was once considerably denser and wetter; it also might have contained oxygen.
"A fundamental question for this mission is whether Mars could have supported a habitable environment," said Michael Meyer, lead scientist for NASA's Mars Exploration Program. "From what we know now, the answer is yes."
A rock sample taken by Curiosity was found to contain hydrogen, carbon, oxygen, clay minerals, and sulfate minerals. Researchers believe the water that aided in the creation of the rocks had a neutral pH.
An Earth bound telescope also noticed an unusual amount of methane gas on Mars' Western hemisphere. The gas is created by animal digestion and plant decay on Earth, but there could be a non-biological explanation. Curiosity was unable to detect any methane, which came as a disappointment to scientists.
NASA hopes the findings will help them map out the evolution of the Martian environment and find more evidence of past microbial life.
"A fundamental question regarding the habitability of early Mars is how long liquid water, in the form of lakes, or even oceans, might have persisted on the surface to support microbial life that may have been present," NASA's Dr. Paul Mahaffy, a leader of the study, said.
The rover found evidence of a snow-capped mountain and a freshwater lake which may have existed before the catastrophic event.
Curiosity's findings are large step towards proving life once existed on the now barren planet.
