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Evidence of flowing water on Mars
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Liquid water has been observed on the planet Mars, the US space agency NASA said yesterday.
“Mars is not the dry, arid planet we thought of in the past,” Jim Green, NASA’s planetary science director, told a press conference in Cape Canaveral, Florida.
“Under certain circumstances, liquid water has been found on Mars.”
Scientists have long believed that water once flowed freely across the red planet and was responsible for forming its valleys and canyons.
Major climate change about three billion years ago is believed to have changed all that, Green said.
“Today we’re revolutionizing our understanding of this planet,” Green said. “Our rovers are finding there’s a lot more humidity in the air.”
The rovers searching the planet’s surface have also found that the soil is much more moist than anticipated. Dark streaks running down slopes on the Martian surface were observed about four years ago.
Scientists did not have proof, however, that these streaks — which would form in spring, grow by summer and then disappear by fall — were actually water. But after careful study and analysis, they are ready to say that these streaks are, in fact, water.
A paper published earlier in the day said scientists have found the first evidence that briny water may flow on the surface of Mars during the planet’s summer months.
Although the source and the chemistry of the water is unknown, the discovery could affect thinking about whether the planet that is most like Earth in the solar system could support microbial life.
Scientists developed a new technique to analyze chemical maps of the Martian surface obtained by NASA’s Mars Reconnaissance Orbiter spacecraft.
They found telltale fingerprints of salts that form only in the presence of water in narrow channels cut into cliff walls throughout the planet’s equatorial region. The slopes, first reported in 2011, appear during the warm summer months on Mars, then vanish when the temperatures drop. Scientists suspected the streaks, known as recurring slope lineae, were cut by flowing water, but had previously been unable to make the measurements.
“I thought there was no hope,” said Lujendra Ojha, a graduate student at Georgia Institute of Technology and lead author of a paper in this week’s issue of the journal Nature Geoscience.
Mars Reconnaissance Orbiter makes its measurements during the hottest part of the Martian day, so scientists believed any traces of water, or fingerprints from hydrated minerals, would have evaporated.
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