Based on images taken over several years from the NASA's Mars Reconaissance Orbiter(MRO), currently orbiting the red planet, there is enough evidence to suggest that liquid water does in fact exist on the surface of Mars today. MRO has been orbiting Mars since 2006.
Using the orbiter's imaging spectrometer, scientists have observed that dark streaks on the Martian surface appear to ebb and flow over time. These darks streaks are known as recurring slope lineae(RSL) and appear to flow down steep slopes during warmer months, then fade away during colder months.
|Recurring Slope Lineae at Hale Crater, Mars|
credit: NASA/JPL-Caltech/Univ. of Arizona
These lineae have been spotted in several locations across the planet, in regions where temperatures average higher than 23 Degrees Celsius.The RSLs are only a few meters in width and average around a hundred meters in length. The space agency now hopes to obtain higher resolution imagery of these surface features using the High Resolution Imaging Science Experiment (HiRISE) on MRO.
Another intriguing find was the discovery of hydrated salts on the slopes which could 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.
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.”
The spectrometer observations show signatures of hydrated salts at multiple RSL locations, but only when the dark features were relatively wide. When the researchers looked at the same locations and RSL weren't as extensive, they detected no hydrated salt.
However Alfred McEwan, Principle Investigator of HiRISE was quick to reassure people at a news conference at NASA Headquarters in Washington that we do not have a situation where there are no streams or rivers of fast flowing water, but rather "Thin layers of wet soil."
In conclusion, it must be said that today will go down in history as the day when humans stopped thinking of the existence of water on Mars as unfathomable, perhaps even laughable, and instead turned it into an opportunity for humans to explore.
In the words of Grunsfeld, "Stay tuned to science because science never sleeps and we've got lots of discoveries(left to make)."
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