A NASA spacecraft circling Mars has found evidence of flowing water
on the Red Planet’s surface – and in our time, not in some dim and more
verdant past.
Humans may like to think Earth has the solar
system’s monopoly on water, but a new study reveals that Earth’s close
neighbor boasts multiple seeps of salt-laden water that were wet, or at least damp, as recently as last year.Until
now, “we thought of the current Mars as a barren, extremely dry and
cold desert,” SETI Institute planetary scientist Janice Bishop, who did
not take part in the research, said via email. “What is new and exciting
here is that this provides evidence for liquid water on Mars in the
current environment.”
Eons ago, Mars had enough water to fill
enormous lakes and rivers. Scientists prospecting for the wet stuff in
recent decades, however, had to content themselves with ice at the
planet’s poles, small amounts of water vapor in the atmosphere and water locked up in minerals in the Martian soil. The wet Mars of billions of years ago seemed to have become a desiccated world.But
five years ago, researchers spotted mysterious dark streaks running
down the warm slopes of Martian craters and mountains. The lines
disappeared in the cold season and reappeared in the warm season, like
spring freshets on Earth. They looked tantalizingly like a sign of
liquid water, but landslides or dust couldn’t be ruled out, study
co-author Scott Murchie of the Applied Physics Laboratory said.
So Murchie and his colleagues had NASA’s Mars Reconnaissance Orbiter
take a closer look. Along the mysterious lines, the spacecraft detected
the signature of waterlogged molecules of perchlorate, chemicals made up
of chlorine and oxygen, the scientists report in this week’s Nature Geoscience.
Something is moistening Mar’s ample deposits of perchlorate, study
leader Lujendra Ojha, a graduate student at the Georgia Institute of
Technology, said. And that something must be liquid water.
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