CAPE CANAVERAL — Mars appears to have flowing rivulets of water, at least in the summer, scientists reported today in a finding that boosts the odds of life on the
“Mars is not the dry, arid planet that we thought of in the past,” said Jim Green, director of planetary science for NASA.
Scientists in 2008 confirmed the existence of frozen water on Mars. Now instruments aboard NASA’s Mars Reconnaissance Orbiter have yielded what researchers said is the strongest evidence yet that water in liquid form trickles down certain Martian slopes.
And because liquid water is essential to life, the finding could have major implications for the possibility of microscopic life forms on Earth’s next-door neighbour.
“It suggests that it would be possible for there to be life today on Mars,” NASA’s science mission chief John Grunsfeld said at a Washington news conference.
The rivulets — if that’s what they are, since the evidence for their existence is indirect — are about 12 to 15 feet wide and 300 feet or more long, scientists said. They apparently consist of wet soil, not standing water.
The water is believed to contain certain salts — not ordinary table salt, but magnesium perchlorate, magnesium chlorate and sodium perchlorate. Like road salt used to melt ice and snow on Earth, such compounds can prevent water from freezing at extremely low temperatures.
That would explain how water could exist in liquid form on Mars, which has an average temperature of minus 85 degrees Fahrenheit.
In addition to supporting life, the presence of liquid water could make things easier for astronauts visiting or living on Mars. Water could be used for drinking and for creating oxygen and rocket fuel. NASA’s goal is to send humans there in the 2030s.
Michael Meyer, lead scientist for NASA’s Mars exploration programme, said the only definitive way for now to determine whether there’s life on Mars is to collect rocks and soil for analysis on Earth, something an American lander set for liftoff in 2020 will do.
“Water is one of the most precious resources necessary for a human mission to the red planet,” Representative Lamar Smith, R-Texas, chairman of the House science, space and technology committee, said in a statement. “The more evidence we find of it, the more encouraged I am for future Mars missions.”
Alfred McEwen of the University of Arizona at Tucson, a scientist on the project, said he, for one, believed the possibility of life on Mars to be “very high”.
The source of the briny water is a mystery. Scientists said it could be melting ice, an underground aquifer, water vapour from the thin Martian atmosphere, or some combination. The evidence of flowing water consists largely of dark, narrow streaks on the surface that tend to appear and grow during the warmest Martian months and fade the rest of the year. Streaks are in places where the temperature is as low as ten below.
They were spotted by the Mars orbiter’s high-resolution, telescopic camera, and another on-board instrument detected the chemical signature of salt compounds combined with water. McEwen said that there appeared to be a “significant volume” of water, speculating it could fill many Olympic swimming pools, but it was spread thin.