Mars, Earth’s arid red neighbor, may have had a more active past than previously believed.
UT research scientist John Holt and his team have found large reserves of ice buried under rock near the mid-latitudes of Mars, which could mean the planet was once flowing with water.
“We haven’t found any evidence of liquid water on Mars yet,” said Holt, who presented his findings Friday. “But it is a possibility.”
Holt is a scientist on the Shallow Subsurface Radar instrument team of the Mars Reconnaissance Orbiter.
NASA launched the orbiter in 2005 to seek out the existence of water on Mars, according to the NASA Web site. One of the orbiter’s main scientific instruments is the Shallow Subsurface Radar, which scans beneath the planet’s crust for water by sending out bursts of energy that reflect off of surfaces, similar to the way bats navigate with echo location, Holt said.
“It’s fascinating how [the radar] can create such detailed images of something trapped underneath layers of dirt and rock,” said geological sciences professor Jay Banner. “It really is a remarkable technological feat.”
Finding subsurface water on Mars is crucial for evaluating the possibility of life on the planet, Holt said.
“Life as we know it is dependent on water,” he said. “Where there is water, we could find habitats, and finding life on Mars would be huge.”
The radar located ice at the middle latitudes of the planet, between 30 and 60 degrees in the northern and southern hemispheres, where the formation of water or ice should not be physically possible.
“Water is completely unstable in the Mars atmosphere and should sublimate at that region,” Holt said. “But the ice sheet is feasible due to variations in the planet’s spin axis, which we believed changed from 15 to 35 degrees over a period of one million years.”
The radar also discovered a 2-kilometer-thick stack of dust and ice roughly the size of Texas at the northern pole of the planet. The composition of these polar layered deposits is approximately 95 percent ice.
“There seems to be enough ice in the deposits to cover the entire surface of Mars in about 30 feet of water,” Holt said.
The water could have formed billions of years ago when scientists believe Mars was a warm planet similar to Earth.
“At some point in the past, Mars was probably warmer and there was water in the atmosphere — rivers and lakes,” Holt said. “Then the planet became colder because of some type of drastic change that we haven’t discovered yet. This might have shut off the planet’s magnetic field that protected the atmosphere. Once the magnetic field was gone, solar winds stripped away the atmosphere along with most of the planet’s water.”
The frozen reserves of water could provide the raw material needed to make oxygen for breathing and hydrogen for fuel, but putting men on Mars is still a long way away, Holt said.
“It would probably take a 20-year mission to put man on Mars,” he said. “When new administrations take office, it makes missions harder to implement because we have to start plans all over again. We’d need a 20-year long presidency.”
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