NASA’ Curiosity robotic rover has recently provided space researchers with additional data on planet Mars’ distant past. Two samples of ancient clay found in the Martian Gale crater show that the planet needed much more time than previous calculated to become the dry wasteland it is today.
Curiosity drilled two holes (photo) in Gale crater and gathered samples of billion-year-old clays. These samples were later analyzed for deuterium and hydrogen trapped within them. Earlier this month, NASA’s scientific rover revealed that the Gale crater held a vast system of rivers and deltas several billion years ago. Scientists also said that Mars might have even have a planetary ocean on its surface before drying out.
Additionally, NASA researchers said that the samples of ancient clay might give them additional clues about what really triggered the ancient Mars dryout. To find more answers, Curiosity analyzed the deuterium and hydrogen ratio present in different layers of ancient clay.
Hydrogen and deuterium are both present within water molecules. After the water had evaporated, hydrogen and oxygen atoms were released into the atmosphere. But, another part of the released hydrogen was reabsorbed by soil. Deuterium, or “heavy hydrogen”, was also trapped inside the layers of ancient clays.
Because hydrogen is lighter than deuterium, it can be easily released into atmosphere and later into space. So, if there are large quantities of deuterium inside the clay, larger amounts of hydrogen have previously been released into atmosphere by water evaporation processes. In short, more deuterium inside clay samples meant more periods of drought on the Red Planet.
Researchers also said that the rate of deuterium-hydrogen in the clay layers could also show how fast the water evaporation process was. It seems that Mars went cold and dry about 3 billion years ago.
The deuterium to hydrogen ration in Martian atmosphere is six times higher than the one of Earth’s oceans. However, previous research involving samples taken from Yamato 980459, a primitive Martian meteorite, showed that ancient Mars had a ratio very similar to Earth’s.
So, researchers believe that Mars had much more water on its surface than it has today. Most of the water currently present on Mars is located at its northern pole and beneath the permanent CO2 ice cap at its southern pole. Present day water on Mars is either ice or vapor.
Curiosity rover found that the D:H ratio inside the new found clay samples was three times higher than the Earth’s. Researchers said that this value was higher than expected. So, ancient Mars have been drying out for a longer period of time.
Scientists now hope that NASA’s MAVEN orbiter which was designed to analyze Martian atmosphere would bring additional data and confirm their previous theory that Mars went dry and cold because it lost a lot of atmosphere to space.
Image Source: Scitech Daily