Recently, NASA announced the discovery of flowing, liquid water on the planet Mars. This water, seeping from the tops of slopes in Valles Marineris, is the first stable water found on the planet. It has long been known that water exists on Mars, though the vast majority of it is locked in the planet’s polar ice caps. This discovery now has the scientific community busily working on the question of whether or not this recently discovered liquid water could support any form of life on Mars.
View of Mars showing Valles Marineris, where indications of flowing liquid water have recently been found.
Deduced from the presence of dark streaks that run down rocky slopes in Valles Marineris, the liquid water that has been discovered to exist on Mars is made possible by the presence of perchlorate salts, which alter the water’s vapor pressure when suspended in a solution. By doing so, these salts lower the point at which the water freezes, allowing it to remain in a liquid state despite the extremely cold average temperature of the Martian surface. The liquid water on Mars was found because of these areas where it occasionally flows onto the surface, but the majority of it, according to University of Arizona researcher Alfred McEwen, is most like contained within “thin layers of wet soil”.
As for the possibility of life on Mars, the presence of liquid water makes it much more likely that life existed on the red planet in the past, and might even today. Liquid water is considered a fundamental requirement for the existence of life as we know it, and it is thought that at one time the atmosphere of Mars was similar to that of Earth. A gamma ray spectroscopy study conducted by the University of Arizona in 2008 suggested that up to a third of the surface of Mars may have been covered in oceans of liquid water at some point in the distant past. Similar studies, including one published the same year in the Journal of Volcanology and Geothermal Research (see sources for full paper) have confirmed that Mars was once volcanically active in a manner consistent with a molten mantle layer. While this itself is not a direct sign of life, a molten mantle suggests that Mars may have once possessed a protective magnetic layer, which is considered one of the critical factors in the development of life on Earth. Some theories regarding the early development of terrestrial life have also suggested that volcanic activity may have played a critical role in creating the chemical conditions necessary for organic compounds to form and begin to develop into living organisms, though this is still theoretical.
Until now, however, stable liquid water had never been observed on the surface of Mars, or on any other planet besides Earth itself. Besides simply contributing to the case that life on Mars might have existed in the past, it also makes it possible that some form of life could potentially have survived in the water on Mars. John Grunsfield, an administrator with NASA’s Science Mission Directorate, stated that “It suggests that it would be possible for there to be life today on Mars”. The InSight probe, set to begin its mission of gathering data about subsurface temperatures and conditions on Mars in 2016, is expected to give scientists a clearer understanding of the source of this liquid water.
Outside of the possibility of harboring life on Mars, it is thought that this water may prove useful to future human expeditions to Mars. The water, though too rich in salts to be potable in its raw form, could be purified for consumption if and when a manned exploration of Mars is undertaken. NASA has suggested that this source of liquid water will be the focus of much future study as exploration of Mars goes forward.
By NASA / USGS (see PIA04304 catalog page) [Public domain], via Wikimedia Commons
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