2024-01-18 16:00:03
It all started when Giovanni Schiaparelli’s planets aligned. The Italian astronomer took advantage of the fact that in 1877 the Earth and Mars were on the same side of the Sun and at the minimum distance between them to draw a series of maps of the neighboring planet. In them, he showed a network of lines that he called “canali” and that sparked countless speculations about the origin of these channels—perhaps drilled by a Martian civilization—and what type of liquid flowed through them. Almost a century and a half later, evidence for the existence of water on the red planet is accumulating. The latter also offers great opportunities for human exploration of the future and the search for life on Mars. Because a mission from the European Space Agency (ESA) has detected clear evidence of the existence of massive blocks of ice in the flat, equatorial area of the planet, the most accessible for landings.
The Mars Express probe, which ESA sent to Mars in 2003, had detected important underground deposits in 2007 in the windy region known as Medusae Fossae (Medusa pits in Latin), but could not determine whether they contained volcanic or other dust. type of sediments. Now, the same instrument and the same scientists, thanks to new radar sweeps over that formation, present clear indications that gigantic ice deposits are hidden there beneath the surface. And they are much larger than what was initially measured: there would be between 219,000 and 396,000 cubic kilometers of frozen water. If it melted, it would flood the entire planet under a layer of about two meters of water. It is more than all the fresh water on Earth in rivers and lakes, and it would be enough to fill the Red Sea.
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“It could be a very valuable resource for future human exploration,” says Thomas Watters, a scientist at the Smithsonian Institution (USA). Water is a very precious commodity for this future planetary exploration, not only to relieve the thirst of astronauts, but also as a source of fuel. “It has the advantage of being located on the equator of Mars and in the northern lowlands, ideal as landing sites,” the main author of the work, carried out with the MARSIS instrument of the Italian Space Agency, adds in response to EL PAÍS. “Medusae Fossae’s ice-rich deposits could help explain where the large volume of water that helped reshape the surface of Mars ended up,” Watters says, referring to channels and other geological formations.
Height map of the Martian surface, with the lowest terrain in blue and the highest in white. At an impressive 22 kilometers high, Mount Olympus is the tallest volcano in the entire Solar System, and the Medusae Fossae Formation is an interesting region for science near the equator.ESA
In 2018, Mars Express located a large lake of liquid water beneath the Martian polar ice. But these massive ice deposits, the largest outside the poles, are in a much more accessible point on the planet. The Medusa pits are on the smooth plains of a region north of the equator, far from the dangerous mountainous terrain to the south, with craters that could jeopardize a landing. As specialist Alberto González Fairén recalls, one of these deposits is just 500 kilometers from the Gale crater, “where we have had the Curiosity rover exploring the terrain for more than 11 years: it is as if we had landed in Valladolid and they detected the presence of ice. in Valencia”. “So close and yet so far for a rover,” laments Fairén, a researcher at the Center for Astrobiology (CSIC-INTA) in Madrid and at Cornell University in New York.
“It is a very interesting discovery,” says Fairén. “It confirms what we have learned in recent decades: these massive ice deposits, if confirmed to be so, confirm that Mars was a planet very rich in liquid water in the past. If the data are confirmed, it would be additional evidence that Mars was a world somewhat more similar to Earth in the past,” summarizes the researcher, who emphasizes the need to verify these data. Watters’ team assures (in the study published in Geophysical Research Letters) that the signals returned by the radar over these deposits can only be explained if there was ice, and that they are very similar to those captured with Martian polar ice. “Very dirty ice, but water ice. If it is confirmed,” insists Fairén, who recalls that the MARSIS team continues to carry out complementary investigations to corroborate the discovery.
Life and astronauts
“It would be of exceptional importance, since it would be ice that could be accessible in the future; in the region of the planet where it is less complicated to land, and where there are more hours of sunshine and the winters are less freezing. It would be an exceptional location to begin exploration with astronauts,” celebrates Fairén. The Artemis program, promoted by NASA and supported by thirty countries (Spain among them), plans to take a manned mission to Mars well into the 2030s, but the first step of the project is to set foot on the Moon again this decade and the plans only get delayed.
This map shows the estimated amount of ice within the Lucus Plunum, Eumenides Dorsum and Amazonis Mensa-Gordii Dorsum deposits, in the Medusae Fossae Formation. Some are up to 3,000 meters thick at some point.Planetary Science Institute/Smithsonian Institution
This ice may provide clues to the climatic history of Mars, how it became so arid and what became of the seas that covered its surface. But water, above all, is a key element for life as we know it. The possible existence of life on Mars in the past when it looked like Earth, but also today. “When there is water, even water ice, life or evidence of past life is possible. Unfortunately, if we are right about the thickness of the dry layer, it will be a challenge to obtain a sample of the ice core,” Watters acknowledges. For Fairén, “interest focuses on the possibility of current life.” With water ice at such low latitudes, it is possible that melt pockets habitable by microorganisms currently occur, at least temporarily. “Of course, for Martian life to exist today, the conditions for biogenesis would have to have been met very early in the geological history of Mars, and that is an enormous question that we are not yet in a position to resolve,” warns the Spanish scientist. .
Watters is committed to sending new missions to the area to be able to clear up the mysteries of that ice, “an excellent site for future explorations with rovers.” “Instruments like ground-penetrating radar would be a good start, a drilling rig would be the most direct way to sample the deposits,” he proposes, “but it would be a significant challenge for a robotic mission.” Fairén agrees, given that the ice is under layers of 300 to 600 meters of land: “The reality is that access to all these deposits is, today, unfeasible. “The technology to install drills on Mars capable of reaching hundreds of meters deep is not yet available.”
However, the CSIC researcher warns that this discovery poses another challenge for astrobiology: “We must take extreme precautions to not bring to Mars, in our exploration vehicles, terrestrial life that could accommodate itself in these interfaces.” “If we contaminate Mars, it would be very difficult to find an answer to the enormous question of whether there ever was Martian life,” warns Fairén. The colonizing spirit of some space plans, with more haste than brains, could forever ruin the dream of understanding if something alive inhabited the Schiaparelli canals.
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