Liquid Water on Mars may be the most important discovery on Mars yet...
On Monday, NASA confirmed that the Mars Reconnaissance Orbiter (MRO) had discovered liquid water on Mars.
Using an imaging spectrometer on the MRO, researchers detected signatures of hydrated minerals in mysterious streaks seen in several locations across the Red Planet. These streaks darken and flow down steep slopes during warm seasons before fading in the cooler, winter seasons.
As John Grunsfeld, astronaut and associate administrator of NASA's Science Mission Directorate in Washington said:
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. This is a significant development, as it appears to confirm that water -- albeit briny -- is flowing today on the surface of Mars.
The flows, known as recurring slope lineae (RSL), have long been thought to be liquid water, but the new findings that these streak contain hydrated salts help explain how liquid water on Mars could actually exist. Basically, the hydrated salts lower the freezing point of the water, allowing the water to become more liquid in the warmer summer months. Researchers say it’s likely a shallow subsurface flow, with enough water wicking to the surface to explain the darkening.
The lead author, Lujendra Ojha, of the report first published September 28 by Nature Geoscience, explained it this way.
We found the hydrated salts only when the seasonal features were widest, which suggests that either the dark streaks themselves or a process that forms them is the source of the hydration. In either case, the detection of hydrated salts on these slopes means that water plays a vital role in the formation of these streaks.
Ojha first noticed these puzzling features as a University of Arizona undergraduate student in 2010, using images from the MRO's High Resolution Imaging Science Experiment (HiRISE). HiRISE observations now have documented RSL at dozens of sites on Mars. The new study pairs HiRISE observations with mineral mapping by MRO’s Compact Reconnaissance Imaging Spectrometer for Mars (CRISM).
The MRO observations show hydrated salts at multiple locations, but only when the dark features were relatively wide. When the researchers looked at the same locations when the streaks weren't as extensive, they detected no hydrated salts.
For Ojha, the findings are proof that the mysterious lines he first saw darkening Martian slopes five years ago are, indeed, present-day water.
When most people talk about water on Mars, they're usually talking about ancient water or frozen water. Now we know there’s more to the story. This is the first spectral detection that unambiguously supports our liquid water-formation hypotheses for RSL.
The discovery is a culmination of efforts over many years using a variety of spacecraft. The most exciting part, however, may be how liquid water could point the way to future discoveries - potentially even life itself. As Michael Meyer, lead scientist for NASA's Mars Exploration Program said:
It seems that the more we study Mars, the more we learn how life could be supported and where there are resources to support life in the future.”
To help explain their findings, Nasa also released an animated video showing the effects the liquid water on Mars has on the Hale Crater, just one of the sites that liquid water on Mars is thought to exist.
The Nature Geoscience paper where NASA's report was published was authored by eight scientists, including the following lead researchers:
- Lujendra Ojha, Georgia Institute of Technology
- Mary Beth Wilhelm at NASA’s Ames Research Center in Moffett Field, California and Georgia Tech;
- CRISM Principal Investigator Scott Murchie of the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland;
- HiRISE Principal Investigator Alfred McEwen of the University of Arizona Lunar and Planetary Laboratory in Tucson, Arizona.
The other contributing researchers come from Georgia Tech, the Southwest Research Institute in Boulder, Colorado, and the Laboratoire de Planétologie et Géodynamique in Nantes, France.