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A team of Italian scientists found the strongest traces of liquid water on Mars.
The apparent water reservoir was detected beneath the southern polar ice cap of the planet using the Mars Express satellite radar from the European Space Agency.
Evidence suggests that about 4.3 billion years ago, Mars was an aquatic world like Earth, with a vast ocean – albeit superficial – covering half of the planet. But the planet eventually lost its magnetic field, which stripped it of its atmosphere and liquid water.
The images of Mars today show a sterile and dusty rocky world. But scientists now know that Mars has some water, in the form of ice. Each of the poles of the planet is composed of both ice water and carbon dioxide ice (dry ice).
There is still no solid evidence of liquid water on the red planet
Evidence suggests that 4.3 billion years ago, Mars was an aquatic world like the Earth, with a vast shallow ocean covering half of the planet. (GSFC / NASA)
Nevertheless, scientists have long wondered if liquid water could still exist under the Mars poles. These new discoveries – published in the journal Science – suggest that this is the case.
Under the South Pole of the planet, in an area called Planum Austral, there is a "well-defined" lake or aquifer possible of 20 square kilometers, which the team suggests as being the only one in the world. liquid water.
"Reduce the possibilities," said Elena Pettinelli, co-author of the journal, badociate professor at the Department of Mathematics and Physics at Universita degli Studi Roma Tre in Rome.
"In a way, we did not want to think that it was water … but really there is no other explanation."
Still, the astronomical community is cautiously optimistic. we find life. – Tanya Harrison, Planetary
In 2015, scientists using NASA's Mars Reconnaissance Orbiter (MRO) reported detecting water flows on the planet after spotting "recurrent slope lineages" . . Since then, debate has continued on whether streaks are due to water or sand.
Canada's Cbadie Stuurman, a radar specialist with the European Space Agency, did not participate in the study. discovering a "Vostok Lake on Mars", referring to the largest subglacial lake of the Earth, located in Antarctica.
Scientists were surprised to find tiny organisms, leading them to speculate that life might exist in inhospitable environments. outside of ours.
"It's huge," she said. "We are talking about Lake Vostok on Mars – today, it's very exciting … if this document is correct."
The Long Research
To draw their conclusions, the Italian researchers used the Mars Advanced Radar MARSIS data) aboard the Mars Express satellite orbiting the planet since 2003.
In 2008, MARSIS detected a zone of light reflection, suggesting the possibility of a liquid under the ice. In 2012, uncertain of what was responsible for this reflection in the radar, the team decided to reacquire data from the same region using different methods.
The team was waiting for the south pole of Mars to be in the dark. erase the signal. Eventually, scientists collected data from 29 orbits – and the thinking was still in the data.
The team spent two more years going through a rigorous process of accounting for other potential sources of thinking. But everything indicated liquid water.
This radiogram illustrates the light reflection that was detected by the MARSIS instrument on the Mars Express orbiter. The upper light line corresponds to the reflection data of the surface. The bottom line is what scientists call the "basal reflection," which they believe to be liquid water beneath the polar cap south of the planet. (R. Osrosei, SE Lauro, E. Pettinelli, et al.)
"When we got to this point, we said," OK, that's something that everyone has been looking for since over 12 years old. "Because this radar was sent to Mars to search for water – it was the main idea," said Pettinelli. "And when we did, we were excited and surprised and a little worried."
Although the team's article has been peer reviewed, the results are based on only one source of evidence. , they found something unnatural in the radar, "said Stuurman." The implications are enormous, if they are correct, but it would be nice to see more evidence to support [beyond the radar]. "
Follow the Water
When it comes to the search for life, scientists always have a guiding principle: to follow the water.If Mars has, indeed, to underground liquid water, then there is a potential for life.
"It's a really exciting discovery," said Tanya Harrison, global scientist and research director for the University State of Arizona Initiative It was not involved in this latest research, but it is involved with NASA's Mars Exploration Robot, Opportunity, and Mars 2020 robot. , which should be launched in two years
"I think this has a huge astrobiological potential. water, we find life, "she said. "So, if there's this thing about 20 ml of liquid brine lying under the ice on Mars, maybe there's some kind of little insect."
The results also add Mars to a growing list of – A list of the Europa moon of Jupiter and Saturn's moon Encelade
A mosaic made from images taken by NASA's Galileo spacecraft at the late 1990s shows the surface of the frozen moon of Jupiter, Europa. It is believed that an ocean exists under its icy crust. "Maybe that's the common thing in the solar system, and the Earth is just weird," Harrison said. "We find all the other bodies that are melting inside, and here we have all the fusion going on outside."
Although the paper does not go into great detail as to the methods and data of the team calculations, Pettinelli hopes to publish another document with this information in the future so that he can to be further badyzed by other planetary scientists.
"As with any scientific discovery, in the future, somebody else can do other research and maybe fix some of those results, but that's part of science, "she said. "We are quite convinced that this is the only possible explanation."
Although Stuurman and Harrison are cautiously optimistic about these new discoveries, they are also excited about what they can tell us about the red planet's past.
"Whatever the outcome of this debate," says Stuurman, "it's exciting for Martian science."
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