The team, using radar instruments (MARSIS) aboard a European Space Agency orbiter, say they found a lake under the polar cap that stretches about 20km across and 1.5km deep.
The researchers, whose work is being published Wednesday in the journal Science, found the lake while studying a region called Planum Australe in the southern ice cap of Mars, researchers said. Boffins have discovered the first-ever liquid water lake on Mars and is thought to be the largest body of liquid water ever found on the Red Planet. If the lake also contains salt deposits, the melting point is reduced even more and keeps the water flowing even at below-freezing temperatures.
"Nobody dares to propose that there could be any more complex life form", Orosei said. In recent years, that has led the space agency to contemplate robot probes to the moons of Jupiter and Saturn, like Europa or Enceladus, where it is now known that salty oceans exist underneath thin shells of ice and where imaginative astrobiologists can envision microbes or more complex creatures. Data from NASA's Cassini orbiter, even though the mission ended in 2017, continues to provide researchers with evidence of organics under the ice of Saturn's moon Enceladus, although they can't yet tell if geology or biology produced those organics (Cassini simply wasn't equipped to tell the difference).
While many subsequent missions were being planned, it took almost two decades before spacecraft again visited Mars.More news: Michael Cohen Not Seeking Pardon From Donald Trump, Attorney Lanny Davis Says
MARSIS used low-frequency electromagnetic waves, transmitting its pulses toward the red planet, researchers explained. Using the patterns they form as they're reflected, inferences can be made about what's hiding underneath the surface.
"This is now our best, albeit slim chance of discovering life elsewhere in our Solar System until the more complex missions to Europa or Enceladus, the moons of Jupiter and Saturn we also believe have subterranean water sources". However, there are [analogous organisms] on Earth, in the subglacial lakes of Antarctica.
Still, he said, "Having a stable body of liquid water today is very intriguing and worthy of study". Orosei estimated the water temperature at somewhere between 14 degrees Fahrenheit (minus 10 degrees Celsius) and minus 94 degrees Fahrenheit (minus 70 degrees Celsius).
Stofan says finding liquid water is something scientists are extremely interested in scientifically, "because life here on Earth evolved in liquid water". The only way we can put life on the planet in the future is to ensure without a doubt that there had been no life on it in the past. "It may exceed the salt content that any terrestrial organisms that we know of can survive in", he said. That reflection is particularly strong at interfaces with liquid water, and shows up as a distinctively bright spot in visualizations of the data.
Early results from Mars Express already found that water-ice exists at the planet's poles and is also buried in layers interspersed with dust. It took them two and a half years, though, from May 2012 to December 2015-to acquire 29 radar profiles. SHARAD operates at different frequencies than MARSIS does, but it's also created to pick up subsurface features.