After the rover Curiosity detected no evidence of carbonate in Mars' rocks, it perplexed the experts.
Self-portrait of NASA's Curiosity Mars rover shows the vehicle at the 'Okoruso' (c) JPL - NASA
It was initially thought that Mars’ atmosphere that is filled carbon dioxide helped melt the planet’s massive ice into rivers, streams and ponds billions of years ago. However, now things turned hazy.
“A higher carbon dioxide pressure in the atmosphere of early Mars could have provided a greenhouse effect with the magnitude required to warm the surface of the planet over the freezing point of water,” said Cornell astronomer Alberto Fairen, a member of the NASA research team in the Proceedings of the National Academy of Science.
Now experts are confused about the true amount of carbon dioxide on Mars, which is a significant factor when considering the planet's ability to support life.
Good luck, there's not enough carbon
“We know that liquid water was flowing and ponding on Mars at that time, as confirmed by Curiosity investigations and other previous and current missions,” said Fairen, a Cornell visiting astronomer from Spain’s Center for Astrobiology in a statement
. “But our results pose a very interesting conundrum. That’s science – a series of questions, not a catalog of answers.”
The experts admitted they were shocked with what the rover brought. The examined sedimentary rock was collected at the Gale Crater on Mars.
“We’ve been particularly struck,” lead author Thomas Bristow of NASA’s Ames Research Center in California and principal investigator for the chemistry and mineralogy (CheMin) instrument on Curiosity told Cornell
NASA's rover Curiosity brought baffling news (c) Baltimore Sun's Darkroom
“It would be really hard to get liquid water even if there were a hundred times more carbon dioxide in the atmosphere than what the mineral evidence in the rock tells us.”
The biggest question now among the experts is, if there wasn’t enough carbon dioxide on Mars about 3.5 billion years ago, what could have melted the ice enough to make liquid water flow?
“We still don't know,” said Fairen.
“It is possible that our climate models are still incomplete and we are missing some pieces of a model to fully understand the puzzle,” said Fairen. “Maybe other gases were present in the atmosphere, capable of providing similar effects to carbon dioxide. Or perhaps the climate was actually cold and the hydrological cycle was similar to that in the polar regions of Earth today.”