Arts said:
https://www.sciencealert.com/vast-liquid-water-reservoir-found-on-mars-radar-planum-australe-subglacial-lake
We finally know where all that Martian water has been hiding!
This latest epic discovery was achieved using a radar instrument on a Mars orbiter, with Italian scientists finding a huge liquid reservoir hidden 1.5 kilometres (0.93 miles) under the southern polar ice cap, extending 20 kilometres (12.4 miles) across.
The researchers say it’s a lot like the subglacial lakes trapped beneath the ice of the Arctic and Antarctica here on Earth. And, like our terrestrial subglacial lakes, it might be where we find surprising life.
etc
It was between May 2012 and December 2015 that the research team seriously investigated a 200-kilometre-wide section of the southern ice cap, in a location called the Planum Australe.
They took 29 radar profiles of the region, bouncing radio waves deep beneath the surface of Mars, and collecting the return signal on a receiver.
It’s by measuring changes between the transmitted signal and what returns that scientists study subsurface features. Radar returning through water is returned more strongly, or ‘brightly’, than radar returning through rock or sediment.
This is what the research team found in their radar results: an anomalously bright region in the Planum Australe.
Other explanations, such as very cold and pure water ice, or carbon dioxide ice, could also explain a brightly reflective subsurface anomaly like this, but the research team ran simulations and found that the reflectivity profile did not match their results as well as liquid water.
But there’s one other big problem: the temperature of the body is estimated to sit at around 205 Kelvin (-68.15 Celsius, or -90.67 Fahrenheit).
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That’s cold, even for high pressure salty water.
Showing the high radar reflection of the bottom of the ice cap.
Showing the triangular shape of lake.
This is quite a small lake. 15 km across. 150 m deep.
