… I mean, it’s not like there’s no H2O anywhere in the Solar System apart from our planet. We know for a fact that a few gas giants’ satellites store substantial quantities of it – think of Europa, for example. What makes the news so exciting is that liquid water is not trapped under the surface like in Europa’s ocean, contained in the Martian regolith or frozen into the Red Planet’s polar caps. Water is flowing right now over the slopes of Martian craters, like Garni, for instance, with dark streaks of a few hundred metres in length.
More details come from NASA’s press release: “Using an imaging spectrometer on MRO, researchers detected signatures of hydrated minerals on slopes where mysterious streaks are seen on the Red Planet. These darkish streaks appear to ebb and flow over time. They darken and appear to flow down steep slopes during warm seasons, and then fade in cooler seasons. They appear in several locations on Mars when temperatures are above minus 10 degrees Fahrenheit (minus 23 Celsius), and disappear at colder times. “Our quest on Mars has been to ‘follow the water,’ in our search for life in the universe, and now we have convincing science that validates what we’ve long suspected,” said John Grunsfeld, astronaut and associate administrator of NASA’s Science Mission Directorate in Washington. “This is a significant development, as it appears to confirm that water — albeit briny — is flowing today on the surface of Mars.” These downhill flows, known as recurring slope lineae (RSL), often have been described as possibly related to liquid water. The new findings of hydrated salts on the slopes point to what that relationship may be to these dark features. The hydrated salts would lower the freezing point of a liquid brine, just as salt on roads here on Earth causes ice and snow to melt more rapidly. Scientists say it’s likely a shallow subsurface flow, with enough water wicking to the surface to explain the darkening.”
(To be true, as the WP has pointed out: NASA has not reported the direct detection of water, but “the detection of chemical signatures consistent with molecules having been hydrated with liquid water.” To me, it’s good enough though).
Mars once had flowing water – no doubt about that. We already knew for example that there were once pools of liquid on the surface, maybe even seas and lakes, like the sample rocks of Garden City, found by the rover Curiosity, have proved. (The frightening conclusion was of course that Mars was once as good for life as the Earth, and then something happened to change it all. What is this something, scientists still have to find out). What is certain is that this new finding will once again have the world’s scientific community looking at it again, with the natural question now being: what can be living in that water.
Life of Mars (bacteria, of course, not intelligent life) has been the object of a few projects during decades, and there are some hints we might already found (and maybe killed) those micro-organisms during the two Viking missions in the 1970s. The two probes actually performed experiments to test for life, apparently yielding positive results (the whole story is still hotly debated: read it here).
No matter the hype, this liquid water will have to wait for an accurate investigation. The rover Curiosity, which is about 50 kilometres from the detection side, simply can’t go there – as it might well be contaminated with all sorts of Earth bacteria. According to the 1967 Treaty of Outer Space warns specifically about fear of contamination: “States Parties to the Treaty shall pursue studies of outer space, including the moon and other celestial bodies, and conduct exploration of them so as to avoid their harmful contamination.” (Art. IX) and staying away from water sources seems just sensible. The most likely solution would be sending robots able to 3D-print (sterile) equipment on the Martian soil (as NASA has recently announced) and using them to investigate. Until the moment humans can do that by themselves, of course.
Whatever the truth, it’s today a proven fact that Mars has all the required components – energy, water, organic chemical – for supporting life. If it does, it’s another story, one that this new discovery will help to find out.
All photo credits: NASA. Watch NASA’s announcement here: