Water on Mars is good news, but there are more challenges up ahead

• Using the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS), a team of Italian researchers discovered liquid water on Mars.
• This is the first sign of a persistent water body on the Red Planet.
  
• The underground lake measures 20 kilometers across and is speculated to be at least 1 meter deeps according to the report published in the US Journal Science.

Water is usually a sign of life, in fact, it's one of the principles of astrobiology. Which is why the discovery of an underground lake by the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) on the red planet is a significant step towards finding life outside the Earth.

Even the Indian Chandrayaan-I’s discovery of water forming on the Moon gave an impetus to the possibility of establishing a manned base on the natural satellite.

But, considering the planet’s temperature and the salt content of the water, it’s very unlikely that any living organisms would be able to survive. There’s also the fact that the Shallow Radar (SHARAD) satellite has been orbiting Mars as well and hasn’t been able to detect the underground lake at all.

Either way, the discovery of water on the planet enhances the possibility of future life on the planet. However, the law of planetary protection also requires that no spacecraft from Earth can land where there is the potential for life, for fear of contamination. Colonisation will only be possible once it’s been determined that Mars has never life forms.

With a pinch of salt

Previous research had discovered some tell tale signs of liquid water being present on Mars, but it was never in a continuous flow. This is the first time that they’ve found a sustained body of water on the planet. Though they aren’t able to determine the exact size of the lake, their data indicates that it’s 20 kilometers across and at least 1 meter deep.

And because Mars has such a thin atmosphere, despite being warm once upon a time, the planet has cooled down and most of the water is locked up in ice. For this water to be in liquid form at subzero temperatures means that the water probably has very high salt content. And, it’s going to be cold.

Which is why most experts on the topic are claiming that though finding water on the planet is a significant discovery, it doesn’t necessitate the presence of life. The temperatures and salt content of the water pose a major obstacle for any living organism to exist.

Deep dive from the sky

The discovery was led by a team of Italian researchers who used the readings sent back by the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS).

On board the European Space Agency’s (ESA) Mars Express Orbiter, the MARSIS is a radar instrument that inspects the surface of Mars and its immediate subsurface as well. It sends out a signal and then examines what is sent back. These ‘reflections’ provide indications of what maybe beneath the surface.

Compiling 29 sets of these radar samplings, the Italian team noticed a sharp change in the signal. The change allowed them to map out the outline of a lake. But here’s the catch. It took them 3 years to calculate the exact size of the subsurface water body because the instrument wasn’t calibrated.

Either way, there are a number of possibilities that open up thanks to this discovery. The most basic of which is that if there’s one lake, there’s got to be more around, right? It’s possible that this lake is only one in a network of lakes in the same south polar region of Mars.