It’s official! In a special press conference this morning, NASA scientists confirmed that liquid water is still flowing on Mars today.
“Mars is not the dry arid planet that we thought of in the past. Today, we’re going to announce that under certain circumtances, liquid water has been found on Mars,”
said Jim Green, director of planetary science at NASA Headquarters.
The press conference focused on a surface feature known as “recurring slope lineae”, or RSL. These dark, thin streaks appear on Martian slopes during the spring, grow through the fall, and disappear during the winter.
Recurring slope lineae on the walls of Mars’ Garni crater. The streaks pictured here are up to a couple hundred meters in length.
(Photo: Mars Reconnaissance orbiter/University of Arizona/JPL/NASA)
For years, scientists have been hypothesizing that these dark streaks could be the result of flowing water, but there was never definitive proof. Until now, that is.
The Mars Reconnaissance Orbiter, which has been circling Mars since 2006, is equipped with a tool known as the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM). CRISM uses spectroscopy to analyze different features on Mars, determining things like mass, temperature and composition by looking at how objects disperse light.
During the press conference, Lujendra Ojha, a researcher from the Georgia Institute of Technology in Atlanta, announced that recent spectroscopic analyses of the dark streaks on Mars have confirmed that they contain hydrated perchlorate salts (hydrated salts are salts with molecular water trapped inside them).
Ojha went on to explain how perchlorates allow water to exist as a liquid at much lower temperatures, adding that the presence of hydrated salts is a strong indicator of “contemporary liquid water” just below the surface of Mars.
“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,”
Ojha said.
More recurring slope lineae, this time on the slopes of the Horowitz crater (Photo: Mars Reconnaissance orbiter/University of Arizona/JPL/NASA)
Where the water is coming from exactly is still a bit of a mystery. There are two prevailing theories, however.
The first is that the water comes from the warming of underground ice. As Ojha pointed out, the briny water on Mars contains very high levels of salt, which makes it melt at lower temperatures. It’s possible that extra warmth from the sun during the spring is enough to melt some of the frozen water trapped under the surface of Mars.
The second possibility is that the damp streaks on Mars are a result of a process called deliquescence. When atmospheric humidity gets high enough, perchlorate salts begin to absorb moisture right out of the air. In fact, they will keep absorbing moisture until they dissolve into a saline (saltwater) solution — that could be what is happening when the recurring slope lineae appear.
Further research is needed to determine the source of the water, but one thing is for certain: the confirmation that liquid water still exists on Mars is increasing the prospects of finding life on the Red Planet.
When asked whether today’s announcement had raised NASA’s odds of finding life, the researchers were somewhat guarded with their responses, but Jim Green suggested that the chances are as good as they have ever been: “Everywhere we go where there’s liquid water … we find life,” he said.
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