QUESTIONS & ANSWERS: MARS

Q Scientists have discovered a huge lake of salty water that appears to be buried deep in Mars, according to a study published in the journal Science. What is the significance?

AEvidence of water has been seen on Mars many times, but it is usually ancient, fleeting or frozen. This discovery is the largest detection of liquid on Mars and raises the possibility of finding life on the planet. “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.

Q How did they do it?

ATo 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 20 kilometre-wide reservoir lies below ice about 1.5 kilometres 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.

Q What do scientists know about it?

AResearchers have not determined how deep the reservoir actually is but estimate it is at least three feet deep, otherwise they would not have detected it at all. This means that scientists can’t specify whether it’s an underground pool, an aquifer-like body, or just a layer of sludge.

Mars is very cold, but the water might have been kept from freezing by dissolved salts.