Mars

JPL-Caltech/MSSS/NASA/Sipa USA

Could Saltwater Lake Found Below Surface Of Mars Host Life?

July 25, 2018 - 4:20 pm
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MARS (WCBS 880/AP) -- A 12-mile-wide saltwater lake has been found below the surface of Mars, fueling a new debate about the prospects of life on the red planet.

The discovery, based on observations by a European spacecraft, generated excitement from experts.

“There’s a spacecraft in orbit around the planet that bounces radar waves off the surface, and because water reflects differently than ice, they were puzzled at first and excited about this very bright reflection, which they tried to disprove themselves every way they could to make sure that they were really right that this was very likely to be water,” Washington Post science reporter Carolyn Johnson told WCBS 880’s Mack Rosenberg.

Water is essential to life as we know it, and scientists have long sought to prove that the liquid is present on Mars.

"If these researchers are right, this is the first time we've found evidence of a large water body on Mars," said Cassie Stuurman, a geophysicist at the University of Texas who found signs of an enormous Martian ice deposit in 2016.

Scott Hubbard, a professor of astronautics at Stanford University who served as NASA's first Mars program director in 2000, called it "tremendously exciting."

Saltwater Lake Found On Mars
Davide Coero Borga/INAF/ESA via AP

"Our mantra back then was 'follow the water.' That was the one phrase that captured everything," Hubbard said. "So this discovery, if it stands, is just thrilling because it's the culmination of that philosophy." 

The lake is about three times the size of the island of Manhattan, and Lee Billings, an editor covering space and physics at Scientific American, said there is little known about it right now. But he said the prospect  of life in the lake is not impossible.

“I doubt there’s fish swimming there, but microbes, maybe so. We have lakes like this under glaciers and ice sheets on earth, and when we drill into those and we get samples of that pristine water, we find that lo and behold, it’s chock full of microbes,” Billings told WCBS 880’s Michael Wallace. “So this is really raising the possibility that life could still exist, or exist in the first place, on Mars.”

The study, published Wednesday in the journal Science, does not determine how deep the reservoir actually is. This means that scientists can't specify whether it's an underground pool, an aquifer-like body, or just a layer of sludge.

To find the water, Italian researchers analyzed radar signals collected over three years by the European Space Agency's Mars Express spacecraft. Their results suggest that a 12-mile-wide reservoir lies below ice about a mile thick in an area close to the planet's south pole.

They spent at least two years examining the data to make sure they'd detected water, not ice or another substance.

"I really have no other explanation," said astrophysicist Roberto Orosei of Italy's National Institute of Astrophysics in Bologna and lead author of the study.

Billings noted that evidence of water has been found on Mars before – from ice caps on the poles to condensation on the NASA Phoenix Lander several years ago. It is also known that Mars once had a lot more water.

“We see signs of oceans, and flowing rivers and lakes that have dried up billions and billions of years ago. So most of it dried up, some of it turned into ice, some of it went into space, and we haven’t really found signs of liquid water up until now,” he said.

Mars is very cold, but the water might have been kept from freezing by dissolved salts. It's the same as when you put salt on a road, said Kirsten Siebach, a planetary geologist at Rice University who wasn't part of the study.

"This water would be extremely cold, right at the point where it's about to freeze. And it would be salty. Those are not ideal conditions for life to form," Siebach said.

Still, she said, there are microbes on Earth that have been able to adapt to environments like that.

Johnson explained that similar bodies of water do exist on earth.

“There are bodies of water similar to this on earth underneath the Antarctic ice sheet, and in those extreme environments, life exists. So scientists who have long been looking for any sign of past or present life on Mars are excited by this, because they think if we look at the earth analogy, this looks like a place where if life ever did exist, it could have receded and potentially taken refuge,” she said.

Orosei said, "It's tempting to think that this is the first candidate place where life could persist" on Mars. He suspects Mars may contain other hidden bodies of water, waiting to be discovered.

Billings said the evidence of the body of water could help scientists learn more about why Mars is such a mostly dry planet.

“I think so. This is basically telling us where some of the water went. Again, that’s the big mystery, is we know. We see these features on Mars – the dried up oceans, the huge canyons cut by the rivers that would dwarf the thing that made the Grand Canyon on earth. And so we wonder where all the water went, and now, increasingly, it’s clear that it went under the ground. It went down there and froze. But some of it didn’t freeze,” he said.

Our planetary neighbor has a popular target for exploration, with rovers on its surface and other probes examining the planet from orbit.

In May, NASA launched another spacecraft, the InSight Mars lander, which will dig under the surface after it reaches a flat plain just north of the Martian equator in November. William Harwood reported that it was the eighth lander NASA sent to Mars. InSight is also the first mission dedicated solely to learning more about the planet's interior in an attempt to glean clues about how rocky terrestrial planets like Earth formed during the birth of the solar system 4.5 billion years ago.

Since 1964, the United States has launched more than 20 robotic spacecraft to the red planet at a cost of more than $20 billion in an evolving campaign to map out the red planet's surface, determine the role of water in its history and to search for signs of past habitability and the organic building blocks of life, Harwood reported.

(© 2018 WCBS 880. The Associated Press contributed to this report.)