Italian researchers working with data from the European Space Agency MARIS orbiter have produced evidence that there is water on Mars. Not a trickle, not a puddle, but a lake more than 12 miles across hiding beneath the ice of Mars’ south pole. The information appears in a new study reported on Wednesday in the journal Science.
Radar profiles collected between May 2012 and December 2015 contain evidence of liquid water trapped below the ice of the South Polar Layered Deposits. Anomalously bright subsurface reflections are evident within a well-defined, 20-kilometer-wide zone centered at 193°E, 81°S, which is surrounded by much less reflective areas. … We interpret this feature as a stable body of liquid water on Mars.
The idea that liquid water could be hiding beneath an ice cap, in a place so cold that even carbon dioxide freezes into solid ‘dry ice,’ may at first seem strange, but similar situations appear on Earth. There are bodies of liquid water trapped beneath the ice sheets of both Greenland and Antarctica.
Just because the term “lake” is being used to describe this liquid water doesn’t imply that it is by any means fresh water. Like trapped, sub-ice “lakes” on Earth, the water on Mars is likely to be loaded down with salts. In 2007, the Mars Phoenix lander conducted tests on Marian soil that detected high amounts of perchlorates (salts containing a ion of the elements chlorine and oxygen). These salts can act as a form of “antifreeze” and it may be that the Martian polar lake is filled with a liquid that is rich with these compounds. With an estimated temperature around -75° C (-103° F), whatever is in this water would have to be much more effective at keeping things liquid than even a high concentration of normal Earthly brine.
Discovery of liquid water on Mars is exciting, especially since it comes on the heels of the recent NASA discovery of ancient organic material and the continued presence of unexplained levels of methane in the Martian atmosphere that vary with the seasons. All of this supports the exciting idea that Mars may have not only supported life in the past, but may still contain some form of life today.
The presence of liquid water would also be an enormous asset to any potential Mars colonists.
Water can be split for making oxygen to breathe, is used in making rocket fuel, and is … water. However, potential settlers should plan on a very deep well, because the Italian data suggests this water is not only extremely cold and saturated with unknown salts, but about a mile below the surface of the polar cap. Previous evidence from a joint NASA-Italian Space Program study indicated a large quantity of water ice at Mars’ south pole, with ice more than two miles thick in some areas.
MARSIS, which stands for Mars Advanced Radar for Subsurface and Ionosphere Sounding, has been orbiting the red planet since 2005 after it hitched a ride as part of the ESA Mars Express mission. It uses a ground-penetrating radar system similar to those used to explore for minerals on Earth. Another orbiter now in place from NASA, the Mars Reconnaissance Orbiter or MRO, also carries a radar system, but it uses a different type of instrument.
In 2015 NASA published a report that water still flows on the surface of Mars, but some of the evidence for this has since been put in doubt by studies indicating that what were seen as “seeps” of water may actually be seasonal rock slides triggered by changing temperatures.
In 2005, NASA solved another mystery of Mars’ south pole: Why isn’t it at the south pole? That is, why is the polar ice cap not centered on the pole, as it is on Earth, or even at the “top” end of Mars? The answer turns out to be a clash of two regional climate systems that pushes the polar cap off to one side by about 100 miles.
And since everything needs a name, how about Condatis Lacus? Condatis was a Celtic deity who was intentionally conflated with Mars as part of the Roman “pick up everyone’s gods and make them fit our pantheon” program. But originally he seems to have been a god of waters, worshiped where two streams flowed together. This may not be a meeting of the rivers, but it would be a memorable bit of liquid, at least.