First lake of liquid water is discovered on Mars

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TAMPA, July 25, 2018 (BSS/AFP) – A massive underground lake has been
detected for the first time on Mars, raising the possibility that more water
— and maybe even life — exists there, international astronomers said
Wednesday.

Located under a layer of Martian ice, the lake is about 12 miles (20
kilometers) wide, said the report led by Italian researchers in the US
journal Science.

It is the largest body of liquid water ever found on the Red Planet.

“This is a stunning result that suggests water on Mars is not a temporary
trickle like previous discoveries but a persistent body of water that
provides the conditions for life for extended periods of time,” said Alan
Duffy, an associate professor at Swinburne University in Australia, who was
not involved in the study.

Mars is now cold, barren and dry but used to be warm and wet. It was home
to plenty of liquid water and lakes at least 3.6 billion years ago.

Scientists are eager to find signs of contemporary water, because such
discoveries are key to unlocking the mystery of whether life ever formed on
Mars in its ancient past, or if it might persist today.

Being able to access water sources could also help humans survive on a
future crewed mission to Earth’s neighboring planet.

This particular lake, however, would not be drinkable, and lies almost a
mile deep (1.5 kilometers) beneath the icy surface in a harsh and frigid
environment.

Whether microbial forms of life lie within is a matter of debate.

Some experts are skeptical of the possibility since the lake is so cold
and briny, and mixed with a heavy dose of dissolved Martian salts and
minerals.

The temperature is likely below the freezing point of pure water, but can
remain liquid due to the presence of magnesium, calcium, and sodium.

“This is a discovery of extraordinary significance, and is bound to
heighten speculation about the presence of living organisms on the Red
Planet,” said Fred Watson, of the Australian Astronomical Observatory.

“Caution needs to be exercised, however, as the concentration of salts
needed to keep the water liquid could be fatal for any microbial life similar
to Earth’s,” added Watson, who was not involved in the research.

– Radar detection –

The discovery was made using radar instruments on board the European Space
Agency’s Mars Express orbiter, which launched in 2003.

The tool is called the Mars Advanced Radar for Subsurface and Ionosphere
Sounding (MARSIS), and was designed to find subsurface water by sending radar
pulses that penetrate the surface and ice caps.

MARSIS “then measures how the radio waves propagate and reflect back to the
spacecraft,” said the study.

These reflections “provide scientists with information about what lies
beneath the surface.”

Lead author Roberto Orosei of the Istituto Nazionale di Astrofisica in
Bologna, Italy surveyed a region called Planum Australe, located in the
southern ice cap of Mars, from May 2012 until December 2015.

A total of 29 sets of radar samplings showed a “very sharp change in its
associated radar signal,” allowing scientists to map the outlines of the
lake.

“The radar profile of this area is similar to that of lakes of liquid
water found beneath the Antarctic and Greenland ice sheets on Earth,
suggesting that there is a subglacial lake at this location on Mars,” said
the report.

– Confirmation needed –

“This is the first body of water it has detected, so it is very exciting,”
David Stillman, a senior research scientist in the Department of Space
Studies at Southwest Research Institute in Texas, told AFP in an email.

However, Stillman, who was not involved in the research, said another
spacecraft, or other instruments, need to be able to confirm the discovery.

He noted that a higher-frequency radar instrument made by the Italian
space agency, SHARAD, on board the Mars Reconnaissance Orbiter launched in
2005, has been unable to detect subsurface water.

“It is strange that SHARAD cannot confirm this discovery. In fact, SHARAD
cannot penetrate through the ice here and no one understands why it can’t,”
Stillman said.

“This suggests that something strange is going on here. Thus, I’m
skeptical about this discovery.”

But researchers are excited about the potential for future finds, because
if liquid water could be found at Mars’ south pole, it might be elsewhere
too.

“There’s nothing special about this location other than the MARSIS radar
on the Mars Express spacecraft is most sensitive to that region meaning there
are likely similar water deposits below the ground all across Mars,” said
Duffy.

 

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