NASA Announces Evidence of Liquid Water on Mars

New findings from NASA’s Mars Reconnaissance Orbiter (MRO) provide the strongest evidence yet that liquid water flows intermittently on present-day Mars.

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.

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.

“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,” said Lujendra Ojha of Georgia Tech in Atlanta, lead author of a report on these findings published September 28 by Nature Geoscience.

Ojha and his co-authors interpret the spectral signatures as caused by hydrated minerals called perchlorates. The hydrated salts most consistent with the chemical signatures are likely a mixture of magnesium perchlorate, magnesium chlorate and sodium perchlorate. Some perchlorates have been shown to keep liquids from freezing even when conditions are as cold as minus 94 degrees Fahrenheit (minus 70 Celsius). On Earth, naturally produced perchlorates are concentrated in deserts, and some types of perchlorates can be used as rocket propellant.

For Ojha, the new findings are more 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,” he said. “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.”

This animation simulates a fly-around look at one of the places on Mars where dark streaks advance down slopes during warm seasons, possibly involving liquid water. This site is within Hale Crater. The streaks are roughly the length of a football field.

[Based on NASA press release. Thanks to John King Tarpinian for the story.]

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17 thoughts on “NASA Announces Evidence of Liquid Water on Mars

  1. Far freaking out.

    I’m a child of the early space age: in the early 1960’s I was a little kid living in London and collecting cards of satellites that came with ice cream bars. The first books I remember dealt with the planets, stars, and space flight. There was also Fireball XL5 but let’s not speak of that.

    My primary interests have changed over the last 50 years, but announcements like this bring back that sense of wonder. I was at the Air & Space Museum in DC when the first pictures came in from Voyager as it approached Saturn. It was a feed from JPL at a time when such a feed was a really big deal. The pictures of the Jovian moons that came in later were amazing. We have maps of Venus and Mars, and even have Google Mars. And now they’ve found water on Mars. Damn.

    If only they hadn’t demoted Pluto.

  2. Rick K, you know, every other blog fetishizes posting first. I find it deeply amusing that for this one, the goal is to post fifth. (also… fifth plus 2!)

    And this is seriously cool news. And to have a press release from NASA about Mars, mere days before the Martian opens? Priceless.

  3. “And to have a press release from NASA about Mars, mere days before the Martian opens? Priceless.
    Perhaps not completely coincidental!” 😉

  4. @Mike Glyer, hey, if it encourages a big wealthy Hollywood studio to subsidize NASA, I’m not entirely against it….

    (Yes, I know, that’s vanishingly unlikely. But one can hope.)

  5. Given this news, and until proven otherwise, I’m going to assume that the plot of the movie is Mark Watney trying to outwit the Wet Bandits all by himself.

  6. NASA and the people who work there are not unaware of public relations. Quite the opposite, they spend a massive amount of their energy figuring out how to get the general public involved and excited because that is the only way to get even a fraction of the funding they need.

    There is no way the timing of the announcement is a co-incidence. And that’s a good thing. I want them to use every weapon in their arsenal to build interest.

  7. See, some of the old science fiction comes true. Now about that colonization of other worlds… 🙂

  8. @Annie Y.:

    See, some of the old science fiction comes true. Now about that colonization of other worlds… 🙂

    Yeah, now we come to the bad-news portion of our story…

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