Mars rover Curiosity has discovered that the surface material of the Red Planet has contributed to the evolution of its atmosphere.
Scientists believed for some time that the condition of the Martian atmosphere was a result of the slow loss of vital elements, but new evidence has suggested that its history is more complex than that.
NASA’s rover is fitted with a Sample Analysis at Mars (SAM) instrument, which has been studying the xenon and krypton gases in Mars’ atmosphere. These gases are good tracers for the evolution and erosion of the atmosphere and a lot of information about them has already come from analyses of Martian meteorites and measurements made by the Viking mission.
WINDJANA, MARS – APRIL/MAY 2015: In this handout composite provided by NASA/JPL-Caltech/MSSS NASA’s Curiosity Mars rover used the camera at the end of its arm in April and May 2014 to take dozens of component images combined into this self-portrait where the rover drilled into a sandstone target called ‘Windjana.’ (Photo by NASA/JPL-Caltech/MSSS via Getty Images)
“What we found is that earlier studies of xenon and krypton only told part of the story,” said Pamela Conrad, lead author of the report and SAM’s deputy principal investigator at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “SAM is now giving us the first complete in situ benchmark against which to compare meteorite measurements.”
By measuring the ratios of certain isotopes of xenon and krypton, researchers have realised that neutrons may have been transferred from one chemical element to another within the surface material of Mars in a process called neutron capture. Their experiments have been described in Earth and Planetary Science Letters.
“SAM’s measurements provide evidence of a really interesting process in which the rock and unconsolidated material at the planet’s surface have contributed to the xenon and krypton isotopic composition of the atmosphere in a dynamic way,” said Conrad.
This analysis was possible using static mass spectrometry to detect the isotopes, a technique for finding gases or isotopes that are only present in trace amounts. However, these experiments mark the first time the process has been used on the surface of another planet.
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