Missing lakes with liquid water finally found on Mars
In our recent #Origin story on Mars, you have read how our never-ending curiosity to explore the mysterious Red Planet has led us to so many surprise findings. Till date, several rovers have been sent to the planet, the latest being NASA’s Perseverance with a mission to explore, study, and collect valuable information to help planetary scientists.
Where did all the water vanish?
Researchers from the California Institute of Technology and NASA’s Jet Propulsion Laboratory (JPL) found evidence of the presence of water on the surface of the Red Planet. According to their study, about four billion years ago, the plant had abundant water – enough to cover the whole planet in an ocean that is about 100 to 1,500 metres deep. There were also water bodies like small pools, lakes, and even deep oceans. But a billion years later, the planet is as dry as a dessert. So where did all the water vanish?
Earlier studies hinted that Mars’ low gravity let water escape into space. But years later, a new theory dismissed that assumption.
Read More: Can NASA Scientists Dig A Hole On Mars?
The discovery!
Recently, the Mars Express mission confirmed this years-old theory of the presence of water on Mars. Created by the European Space Agency, the mission’s Mars-orbiting spacecraft discovered new liquid water ponds buried under the ice in the south polar region of Mars. This discovery also shows that about 30 to 99 per cent of the earlier missing water is also ‘trapped’ within minerals in the planet’s crust.
Earlier in 2018, the rover revealed one underground reservoir hinting at a possible habitat of life. But that finding was based on just 29 observations made from 2012 to 2015, which many researchers considered as ‘less enough’ to support the claim. The latest discovery confirmed that the lakes are spread over about 75,000 square kilometres — an area roughly one-fifth the size of Germany! The largest, central lake measures 30 kilometres across and is surrounded by three smaller ponds, each a few kilometres wide.
How did Mars Express discover the missing water?
Publishing in the Science journal, the planetary scientist Elena Pettinelli at the University of Rome said, “this time, we use a broader data set comprising 134 observations from 2012 to 2019. Along with that, the new radar instrument MARSIS also helped in identifying these hidden ponds by cruising the rocks.”
What is MARSIS?
Mars Advanced Radar for Subsurface and Ionosphere Sounding or MARSIS is a low frequency, pulse-limited radar sounder with a 40-meter long antenna. It sends out radio waves that bounce off layers of material in the planet’s surface and subsurface to locate water bodies and other materials. It can also characterise the surface elevation, roughness, and radar reflectivity of the planet to study the interaction of the atmosphere and solar wind in the red planet’s ionosphere. This technique is also used in radar sounder investigations of subglacial lakes in Antarctica, Canada, and Greenland.
Also Read: The story of life on Mars through rovers
Too salty to drink
It is thought that any underground lakes on Mars must have a reasonably high salt content for the water to remain in liquid form. This could be a reason to not support any microbial life forms. “Lakes with a salt content that is about five times that of sea-water can support life, but as the concentration approaches 20 times that of sea-water, life is no longer present,” says John Priscu, an environmental scientist at Montana State University in Bozeman.
The debate
The presence of Martian pools is still a heated debate. While the recent finding supported the 2018 observation with more data, several researchers have also raised concerns such as the lack of an adequate heat source to turn the ice into water. Mike Sori, a planetary geophysicist at Purdue University in West Lafayette, Indiana, for instance, says, “If the bright material is liquid water, I think it’s more likely to represent some sort of slush or sludge.”
What other findings do you expect from Mars? Do tell us in the comments below.