Is water present on Mars? Scientists have been debating this question since at least the 18th century, when astronomer Giovanni Schiaparelli used a telescope to observe Mars and thought he saw canals. A new compelling study suggests that a large lake of water exists beneath Mars' south polar ice cap. The study sheds new light on the subject, implying that there may be liquid water on Mars after all.
The science and other important information
The European Mars Express orbiter discovered in 2018 that
the surface of the ice cap covering Mars' South Pole dips and rises, implying
that liquid water could be lurking beneath. However, not all scientists were
convinced at the time. Mars is extremely cold, and for subglacial water to
exist in liquid form on the planet, there must be a source of heat, such as
geothermal energy.
Some researchers speculated at the time of the Mars Express
discovery that the strange radar signal could be explained by something else,
such as dry material beneath the ice caps. However, an international team of
scientists led by researchers from the University of Cambridge recently used a
different technique to investigate the ice-sheet-covered region and concluded
that the presence of liquid water is the most likely explanation.
Using NASA's Mars Global Surveyor satellite laser-altimeter
measurements to map the topography, or shape, of the ice cap's upper surface,
the researchers discovered subtle patterns of height differences that matched
computer model predictions for how a body of water beneath the ice cap would
affect its surface, according to the study.
"The new topographic evidence, our computer model
results, and the radar data make it much more likely that at least one area of
subglacial liquid water exists on Mars today," said Neil Arnold, professor
at Cambridge Scott Polar Research Institute and the study's lead author, in a
press release.
What's the big deal?
While not everyone agrees that there is liquid water on
Mars, if it is proven to exist beneath the Red Planet's surface, it may give
rise to hope for the existence of hardy microbial life on the Red Planet.
"Liquid water is an essential component of life, but
this does not necessarily imply that life exists on Mars," said Frances
Butcher, the study's second author. "In order to be liquid at such cold
temperatures, the water beneath the South Pole may need to be extremely salty,
making any microbial life difficult to inhabit." It does, however, provide
hope that there were more habitable environments in the past when the climate
was less harsh."
What comes next?
The data returning from Mars, both from orbital satellites
and landers, is of such high quality that we can use it to answer extremely
difficult questions about conditions on and beneath the planet's surface. And
scientists are employing the same techniques that they do on Earth.
Reference(s): Nature Astronomy journal