Liquid Water Lake in Mars

What is the issue?

• Scientists have recently discovered a liquid water 'lake' in Mars.
• This is expected to facilitate a better understanding on the likely presence of life on Mars.

What is the recent finding?

• Mission - An 11-member Italian team of researchers surveyed the Planum Australe region, or the southern polar plains of Mars.
• They used the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) instrument.
• This is a low-frequency radar on board the European Space Agency’s Mars Express Orbiter.
• The instrument beams radar pulses down to the planet's surface and measures how the waves reflect back to the spacecraft.
• This would give information on the kind of materials, even below the surface.
• Findings - The team had discovered a lake stretching for 20-km.
• It is found 1.5 km under the southern polar ice cap of Mars.
• Despite temperatures at about -68° C, the water remains in a liquid form.
• The radar profile of the lake closely matches those of subglacial lakes on Earth, beneath the ice sheets of Greenland and Antarctica.

How in liquid form?

• Atmospheric pressure on the Martian surface is almost a hundred times less than on Earth.
• This ensures that water would not be in liquid form, but rather, as ice or vapour.
• So the presence of water is much beneath the surface.
• The liquid form could be due to the heavy presence of sodium, magnesium and calcium salts.
• This may reduce the temperature and help it retain liquid form.
• This, along with the immense pressure of the ice from above, lowers the freezing point.

What is the significance?

• The majority of modern Mars is dry and barren.
• But plenty of evidence has been found that the Red Planet used to be a much wetter place.
• However, any liquid water was believed to be transitional, in short-lived pools or flowing down hillsides in the Martian summer.
• So the discovery of a large, stable, stagnant lake on Mars is significant.
• It offers new potential targets for future missions and places, to search for signs of past or present microbial life.
• However, the sheer saltiness of the spot raises doubts to this belief.

Source: Indian Express, NewAtlas