After the excitement of scraping up slivers of what turned out to be ice on Mars this summer, NASA announced late Thursday that it has discovered vast glaciers hidden under rubble. One glacier is three times the size of the city of Los Angeles and up to a half-mile thick, according to an alert from NASA’s Jet Propulsion Laboratory. The glaciers were spotted by the Mars Reconnaissance Orbiter, which in late September also sent back information about fractures in the surface of the Red Planet that once directed water flows through underground sandstone. The Mars Lander recently lost power and died on the northern pole of Mars after spending five months searching for elements that could support life there. In June, the lander’s robotic arm successfully scooped up fragments of Martian ice — a major find, since water is an essential element to support life and the ice someday could be used to support manned missions to Mars.
Then in July, the Jet Propulsion Laboratory reported that its scientists had concluded that Mars was once awash in water. The orbiter sent back information showing that water was on Mars as far back as 4.6 billion to 3.8 billion years ago. On Thursday, NASA reported that the glaciers were found under blankets of rocky debris at much lower latitudes than any other ice discovered so far. The orbiter’s ground-penetrator radar reportedly shows that the glaciers shoot out for dozens of miles, from the base of mountains or cliffs. It’s possible that the glaciers are remnants of a massive ice sheet that grew during an ice age on the planet. “Altogether, these glaciers almost certainly represent the largest reservoir of water ice on Mars that is not in the polar caps,” said John W. Holt of the University of Texas at Austin, the lead author of the report. “In addition to their scientific value, they could be a source of water to support future exploration of Mars.” Scientists likened the Martian glaciers to ones that have been found under rocky coverings in Antarctica, according to NASA. Jeffrey J. Plaut, a geologist at the Jet Propulsion Laboratory, said in a statement that the orbiter spotted what might be even larger glaciers in northern areas of the planet. “A key question is how did the ice get there in the first place?” said James W. Head, professor of geological sciences at Brown University, in a statement. “The buried glaciers make sense as preserved fragments from an ice age millions of years ago. On Earth, such buried glacial ice in Antarctica preserves the record of traces of ancient organisms and past climate history.”