MADRID 9 Oct. () –
NASA’s ‘Curiosity’ robot, which is exploring one of the craters on Mars, has provided new details that explain how the planet went from being potentially habitable thanks to evidence of liquid water on the surface, to an area inhospitable to terrestrial life as it is today.
All this data has been collected by David Burtt, from NASA’s Goddard Space Flight Center in Maryland (United States), who is the lead author of an article describing this research, published in ‘Proceedings of the National Academy of Sciences’.
Precisely, the surface of Mars — “icy and hostile” as NASA describes it — continues to be the study surface for many explorers of the American organization, which continues to search for clues about whether life existed in the past on the planet. To do this, they have measured the isotopic composition of carbon-rich minerals found in Gale Crater.
“The isotopic values of these carbonates point to extreme amounts of evaporation, suggesting that these carbonates likely formed in a climate that could only support transient liquid water. Our samples are not consistent with an ancient environment with life on the surface of Mars. , although this does not rule out the possibility of a subterranean biosphere or a surface biosphere that began and ended before these carbonates formed,” Burtt explained.
Isotopes, NASA explains, are versions of an element with different masses that as water evaporates, the light versions of carbon and oxygen are more likely to escape into the atmosphere, while the heavy versions are left behind. more frequently, accumulating in greater quantities.
Scientists are interested in these materials because of their ability to act as climate records since these minerals can retain data about the environments in which they formed, including water temperature and acidity, and the composition of water and atmosphere.
Thus, the aforementioned article proposes two formation mechanisms of the carbonates found in the crater of the Red Planet. In the first scenario, carbonates form through a series of wet and dry cycles within Gale Crater and in the second, carbonates form in very salty water under cold conditions that form ice in the crater.
Even so, these possible climate scenarios for ancient Mars had already been proposed based on the presence of certain minerals, on global scale models and on the identification of rock formations, but this latest study is the first to add isotopic evidence from rock samples. in support of the scenarios.
“The fact that these carbon and oxygen isotope values are higher than anything measured on Earth or Mars indicates that a process is being taken to the extreme,” Burtt said. “While evaporation can cause significant changes in oxygen isotopes on Earth, the changes measured in this study were two to three times greater. This means two things: that there was an extreme degree of evaporation that caused these isotopic values to be “so high, and that these higher values were conserved, so any process that created lighter isotopic values must have been significantly lower in magnitude.”
This discovery, which was funded by NASA’s Mars Exploration Program through the Mars Science Laboratory project, was made with the Sample Analysis at Mars (SAM) and Tunable Laser Spectrometer (TLS) instruments aboard the Curiosity rover. . The SAM heats the samples to nearly 1,652 degrees Fahrenheit (almost 900°C) and then the TLS is used to analyze the gases produced during that heating phase.
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