For almost a decade, the Curiosity rover has been delivering important data about Mars. These relate in particular to the physics and chemistry of the rocks of the Gale crater, which once contained a large body of water. US researchers recently found similar rocks on Earth to assess the actual climate of Mars 3.5 billion years ago.
Curiosity data is insufficient
Since 2012 and the start of the NASA Curiosity rover’s mission, the latter has been exploring Gale crater. It is an impact crater of approximately 155 km in diameter located in the Aeolis quadrangle. However, many researchers agree that a long time ago, this area was home to a lake. However, the question of the climate of the planet Mars is still the subject of debate. Indeed, some scientists believe that Mars experienced a hot and humid period during which lakes and rivers were very present. Others believe that the Red Planet was drier and covered with glaciers. However, the information that the Curiosity rover regularly delivers are not enough to rule clearly on this issue.
A team of researchers from Rice University (United States) published a study in the journal JGR planets January 11, 2021. Scientists explain that they have compared the rover’s data with geological information obtained on Earth.
Earth, this excellent laboratory
According to the study, a very serious candidate was selected: Iceland. Its basaltic terrain and rather cool weather throughout the year (3 ° C on average) are conditions most similar to those of Mars 3.5 billion years ago. According to the team, the sedimentary rocks of Gale crater would have been the subject of a digging past in the two scenarios mentioned above. At that time, Mars may have had a freezing climate, however able to hold liquid water in lakes for long periods.
“The range of climates on Earth allowed us to calibrate our thermometer to measure the temperature on Mars at the time. The Earth provided us with an excellent laboratory to observe the effects of different climatic variables on the weathering of rocks. On Mars, the temperature had the strongest effect ”, stated in a statement Kirsten Siebach, one of the study’s authors.
It should be noted that the study leaders took into account a wide range of terrestrial rocks in order to build their hypothesis. The rocks therefore came from Iceland but also from the Hawaiian archipelago, or from the Antarctic continent.