The Curiosity Rover, which landed on Mars in 2012, explored various aspects of Gale Crater on Mars to understand more about this transition from hot and wet to dry and very cold.
The latest study, collected from data collected by one of the rover’s instruments, suggests that Mars actually switched back and forth between wetter and drier times before completely losing its surface water about three billion years ago.
Curiosity has been climbing Mount Sharp, located in the center of the Gale Crater, gradually since 2014.
An instrument called ChemCam sits on the machine and contains a high-resolution camera and laser that can vaporize rocks to help analyze the chemical composition. ChemCam has an infrared laser that can heat rocks up to 18,000 degrees Fahrenheit. It evaporates the rock and creates plasma, which enables scientists to essentially look at the minerals and chemicals that the rock contains and look back at the geological history of the planet.
The camera on ChemCam was used to record observations of Mount Sharp’s site, revealing cuts from the Martian past as the rock varies.
A Mars history lesson
Mount Sharp is an interesting feature on Mars, as it is one of the best ways the red planet has recorded the history of its climate, water and sediment.
“A primary goal of the Curiosity mission was to study the transition between the habitable environment of the past, to the dry and cold climate that Mars now has. These rock layers recorded the change in detail,” said Roger Wiens, study co-author on paper and ChemCam team scientist at the Los Alamos National Laboratory, in a statement.
Orbiters around Mars have previously recorded information about the minerals in Mount Sharp’s slopes. Data of the curiosity yielded even more detailed observations from the low sedimentary rocks and revealed dry and wet periods in the past of the planet.
Curiosity detects major changes in layers
As Curiosity climbed Mount Sharp, the lows changed dramatically.
The base of Mount Sharp is made of clay deposited at the lake that once filled the crater. Above are layers of sandstone that still preserve evidence of how they were formed by wind dunes during the drier times. Lying above shows more depositions of the floodplain, indicating when wet conditions return to Mars.
Curiosity’s observations show that these changes between wet and dry periods were large – scale events that alternated until the planet became permanently arid. Mount Sharp’s climate record allowed Curiosity to grind in a time of 2.9 billion to 3.7 billion years ago.
As the rover continues its mission, Curiosity will continue to climb the foothills of Mount Sharp and use the drill to further investigate the types of rock and what they reveal. It can provide more insight into the cause of such drastic climate fluctuations.