(CNN) – Mars was a hot, humid planet that was probably capable of supporting life billions of years ago. Something has caused the planet to lose its atmosphere and become the harsh and frozen desert it is today.
The Curiosity rover, which landed on Mars in 2012, explored various aspects of the Gale crater on Mars to understand more about this transition from hot and humid to dry and very cold.
The latest study, compiled from data captured by one of the rover’s instruments, suggests that Mars actually made the transition between wetter and drier times before completely losing its surface water about 3 billion years ago.
This composite image looking at the upper regions of Mount Sharp was made on September 9, 2015 by NASA’s Curiosity rover.
The Curiosity Rover has been climbing Mount Sharp for almost 5 kilometers, located in the center of Gale Crater, since 2014.
An instrument called the ChemCam is on the rover’s mast and includes a high-resolution camera and a laser that can vaporize rocks to help the rover analyze their chemical composition. ChemCam has an infrared color laser that can heat pieces of rock to 18,000 degrees Fahrenheit (almost 10,000 degrees Celsius). This vaporizes the rock and creates plasma, allowing scientists to look essentially at the minerals and chemicals that make up the rock and look back at the geological history of the planet.
The ChemCam camera was used to capture observations of Mount Sharp terrain, revealing slices of the Martian past as the rock varied.
A history lesson on Mars
Mount Sharp is an interesting feature of Mars, as it is one of the best ways in which the red planet has recorded the history of its climate, water and sediments.
“A major goal of the Curiosity mission was to study the transition between the living environment of the past and the cold, dry climate that Mars now has. These rock layers have recorded this change in detail, “Roger Wiens, a co-author of the paper and a ChemCam scientist at the Los Alamos National Laboratory, said in a statement.
The study was published last week in the journal Geology.
Orbiters around Mars have previously recorded information about minerals on the slopes of Mount Sharp. Curiosity data provided even more detailed observations of sedimentary rock layers and revealed dry and wet periods in the planet’s past.
Curiosity detects large changes in the layers of the planet
As Curiosity climbed Mount Sharp, the layers changed dramatically.
The base of Mount Sharp is made of clay deposited by the lake that once filled the crater. Above are layers of sandstone that still have evidence of how they were formed by wind-shaped dunes in drier periods. The above layers reveal several floodplain deposits, indicating when wet conditions returned to Mars.
Observations of curiosity show that these changes between the wet and dry seasons were large-scale events that alternated until the planet became permanently arid. The climatic history of Mount Sharp has allowed Curiosity to focus on a time stretching from 2.9 billion to 3.7 billion years ago.
As the rover continues its mission, Curiosity will continue to climb to the foot of Sharp Mountain and use its drill to further explore the types of rocks and what it reveals. This could provide more information about the cause of such drastic fluctuations in weather.