Scientists have reported signs of liquid water on the surface of Mars, on 28 September, which was otherwise known as a dusty and lifeless planet.
Alfred S McEwen, a professor of planetary geology at the University of Arizona and the principal investigator of images from a high-resolution camera on NASA’s Mars Reconnaissance Orbiter, said, “Water has been detected in the form of hydration of salts. Liquid water produced the hydrated salts.”
In a paper published in the journal Nature Geoscience, McEwen and other scientists identified waterlogged molecules — salts of a type known as perchlorates — in readings from the orbit. Many mysteries remain. For one, scientists do not know where the water is coming from.
The average temperature of Mars is about minus 70 degrees Fahrenheit, but summer days near the Equator can reach an almost balmy 70.
Although young Mars was inundated by rivers, lakes and maybe even an ocean a few billion years ago, the modern moisture is modest. Scientists have long known that large amounts of water still remain, but in a frozen form in the polar ice caps. There have been fleeting hints of recent liquid water, but none have proved convincing.
Lujendra Ojha, a graduate student at the Georgia Institute of Technology, turned to an instrument on the orbiter to identify various molecules by the colours they absorb. “There are definitely some sort of liquid water,” said Ojha said.
In 2011, he and his colleagues discovered in photographs from the Mars Reconnaissance Orbiter streaks descending along slopes of craters, canyons and mountains.
Thousands of recurrent slope lines, or RSLs, have now been spotted. “It’s surprisingly extensive,” said McEwen. Scientists suspect that water played a vital role in the phenomenon.