A research group led by Lund University in Sweden has investigated a meteorite from Mars using neutron and X-ray tomography. The technology, which is likely to be used when NASA examines samples from the red planet 2030, showed that the meteorite had limited exposure to water, making life at the specific time and place unlikely.
In a cloud of smoke, NASA’s spacecraft Perseverance parachuted on the dusty surface of Mars in February 2021. For several years, the vehicle will skid around and take samples to try to answer the question posed by David Bowie in Life on March 1971. It is not. until around 2030 that NASA actually intends to send the samples back to Earth, but material from Mars is already being studied – in the form of meteorites. In a new study published in The progress of scienceAn international research team has studied an approximately 1.3 billion-year-old meteorite using advanced scanning.
– Since water is central to the question of whether there has ever been life on Mars, we wanted to investigate how much of the meteorite reacted with water when it was still part of Mars’ bedrock, explains Josefin Martell, doctoral student in geology at Lund University.
To answer the question of whether there was any major hydrothermal system, which is generally a favorable environment for life to occur, the researchers used neutron and X-ray tomography. X-ray tomography is a common method of examining an object without damaging it. Neutron tomography was used because neutrons are very sensitive to hydrogen.
This means that if a mineral contains hydrogen, it is possible to study it in three dimensions and see where in the meteorite the hydrogen is. Hydrogen (H) is always of interest when scientists study material from Mars, because water (H2O) is a prerequisite for life as we know it. The results show that a fairly small part of the sample seems to have reacted with water and that it was therefore probably not a large hydrothermal system that gave rise to the change.
“A more plausible explanation is that the reaction took place after small accumulations of underground ice melted during a meteorite impact about 630 million years ago. This does not mean, of course, that life could not have existed elsewhere on Mars, or that it could not have been life at other times, says Josefin Martell.
The researchers hope that the results of their study will be helpful when NASA takes back the first samples from Mars around 2030, and there are many reasons to believe that the current technology of neutron and X-ray tomography will be useful when this happens.
“It would be fun if we had the opportunity to study these samples at the European Spallation Source research facility, ESS in Lund, which will then be the world’s most powerful neutron source,” concludes Josefin Martell.