Liquid water spied deep below polar ice cap on Mars.

Pedro_P

Liquid water lies unseen under ice (white) at Mars’s south pole in an image from Mars Express.ESA/DLR/FU Berlin/CC BY-SA

▼ Far beneath the deeply frozen ice cap at Mars’s south pole lies a lake of liquid water—the first to be found on the Red Planet. Detected from orbit using ice-penetrating radar, the lake is probably frigid and full of salts—an unlikely habitat for life. But the discovery, reported online today inScience, is sure to intensify the hunt for other  buried layers of waterthat might be more hospitable. “It’s a very exciting result: the first indication of a briny aquifer on Mars,” says geophysicist David Stillman of Southwest Research Institute in Boulder, Colorado, who was not a part of the study.
The lake resembles one of the interconnected pools that sit under several kilometers of ice in Greenland and Antarctica, says Martin Siegert, a geophysicist at Imperial College London, who heads a consortium trying to drill into Lake Ellsworth under West Antarctica. But the processes that gave rise to a deep lake on Mars are likely to be different. “It will open up a very interesting area of science on Mars,” he says.
Water is thought to have flowed across the surface of Mars billions of years ago, when its atmosphere was thicker and warmer, cutting gullies and channels that are still visible. But today, low atmospheric pressures mean that any surface water would boil away. Water survives frozen in polar ice caps and in subsurface ice deposits. Some deposits have been mapped by the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS), an instrument on the European Space Agency’s Mars Express orbiter, which launched in 2003. MARSIS beams down pulses of radio waves and listens for reflections. Some of the waves bounce off the surface, but others penetrate up to 3 kilometers and can be reflected by sharp transitions in the buried layers, such as going from ice to rock.
Several years into the mission, MARSIS scientists began to see small, bright echoes under the south polar ice cap—so bright that the reflection could indicate not just rock underlying the ice, but liquid water. The researchers doubted the signal was real, however, because it appeared in some orbital passes but not others.
Later the team realized that the spacecraft’s computer was averaging across pixels to reduce the size of large data streams—and in the process, smoothing away the bright anomalies. “We were not seeing the thing that was right under our noses,” says Roberto Orosei, a principal investigator (PI) for MARSIS at the Italian National Institute for Astrophysics in Bologna.
To bypass this problem, the team commandeered a memory chip on Mars Express to store raw data during short passes over intriguing areas.  (▪ ▪ ▪)

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bookie

Very good news. It will help in getting more funding for the space research.

bsk

interesting