Early Mars didn't have enough CO2 to keep water liquid: NASA

WASHINGTON - A new study based on data collected from a Mars rover indicated that the early Martian atmosphere did not contain enough carbon dioxide to keep the planet warm enough for liquid water.

The research, published in the Proceedings of the National Academy of Sciences on Monday, said although geological evidence from the NASA's Curiosity rover suggested the past presence of liquid water on Mars, the red planet had far too little carbon dioxide about 3.5 billion years ago to provide greenhouse-effect warming to thaw water ice.

The Curiosity collected rock samples from Gale Crater, which scientists believe was home to an ancient lake, but did not find any definitive proof for the existence of carbonate.

When carbon dioxide interacts with water on the surface of the Earth, it undergoes chemical reactions to produce carbonate, which can then interact with other elements and compounds to produce carbonate minerals at the bottom of bodies of water.

However, the rover has made no definitive detection of carbonates in any lakebed rocks sampled since it landed in Gale Crater in 2011, the study said.

Although Mars is now cold and dry, there is lots of evidence suggesting that the planet's surface was once covered with rivers, streams and lakes, forming a favorable condition for the development of life.

"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 tell us," Thomas Bristow from NASA said in a statement.