The spacecraft directed by NASA’s Curiosity mission has detected boron in the calcium sulfate mineral veins of the red planet , indicating that this chemical element was present in its groundwater and that these had favorable conditions for life.
Boron had previously been found in meteorites of Martian origin, but this is the first time it has been discovered in the territory of Mars itself. The discovery, produced in the Gale crater, has been possible thanks to the ChemCam , a spectrometric instrument whose laser is capable of pointing at a rock 13 meters away and collecting the spectrum of light that it emits to analyze it later.
“Because borates play an important role in the production of RNA, one of the basic components of life, the discovery of boron on Mars supports the possibility that life could arise on the planet “, explains Patrick Gasda, researcher at the Laboratory Nacional de Los Alamos which, in collaboration with the French National Center for Space Studies. Gasda also developed the ChemCam for the mission.
Boron combines with oxygen and other elements, giving rise to borates, which are frequently found in nature in oceans, sedimentary rocks, coal … On Earth, boron is one of the components of all known forms of life ; on Mars, its presence suggests that the water had the appropriate characteristics to give rise to the chemical reactions necessary for the origin of microorganisms.
RNA, a key molecule for life
Without RNA there is no life ; to the point that scientists have developed the RNA world hypothesis , according to which life arose on Earth thanks to the activity of RNA molecules. In this way, the first prokaryotic cells would have originated from individual strands of RNA , which contained genetic information capable of being copied.
Ribose, a type of sugar, is an essential ingredient in this nucleic acid, but it is unstable and needs another element to stabilize it. This is the function of boron, which, by dissolving in water and reacting with ribose to form a borate, stabilizes the medium sufficiently to produce RNA . “The presence of boron on Mars tells us that these chemical reactions were possible and could have happened there as well,” Gasda details.
According to the study, published in the journal Geophysical Research Letters , the researchers are still considering hypotheses that explain the presence of boron in the veins of the Gale crater .
Although they still do not know the sources of groundwater origin in the past of Mars, they are clear that it has suffered variations in its Eh, pH and chemical composition over time; Furthermore, they know that this complex and variable water system could have been habitable with a temperature between zero and sixty degrees Celsius, suitable for life.
This is just one of the findings that have been made about the composition of the rocks of Mars and, although it is still unknown if there has been life on the red planet, the Curiosity mission is fulfilling its objective of clarifying whether the planet’s environment was habitable or not. For now, the discovery of boron suggests that it does.
Image: A selfie from NASA’s Curiosity rover at the Murray Buttes in the Mars Gale Crater, a location where boron was found in veins of calcium sulfate./NASA/JPL-Caltech/MSSS
Reference:
Gasda, PJ, et al. (2017), In situ detection of boron by ChemCam on Mars, Geophys. Res. Lett., 44, doi: 10.1002 / 2017GL074480.
