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posted by Fnord666 on Thursday November 23 2017, @11:17PM   Printer-friendly
from the look-for-signs-of-salmon dept.

Evidence for liquid water on the surface of Mars may have actually been evidence of sand movement:

One of [Alfred] McEwen's most important finds [on Mars] came in 2011, with the discovery of recurring slope lineae (RSL), thousands of temporary streaks along steep slopes, mostly near the equator, that gradually grow and darken as spring turns to summer, as if fed by seeps of water. They soon became cited as the best evidence for liquid water on the surface of Mars today—and also one of the best places to search for microbial life.

But McEwen has now dowsed some of the excitement ignited by his initial finding. In a study published online this month in Nature Geoscience, he and his colleagues analyzed 151 of the streaks, finding that they only occur on slopes steeper than 27° and always peter out when the angle drops below that [DOI: 10.1038/s41561-017-0012-5] [DX]. The researchers interpret this as a sign that the RSL are not formed by water—which would flow down shallower slopes—but rather are dry flows of sand and dust seeking their natural angle of repose.

But there's still hope for life on Mars... or beneath it:

Q: Do you think of Mars as a hospitable place?

A: It's inconceivable to me that there aren't places where there's liquid water today within Mars. If there was ever life on Mars—that originated somewhere—why wouldn't there still be life today in these underground pockets? The surface, on the other hand, is a very harsh environment for life.

Q: Should the search for life be focused on Mars? Or should NASA and other agencies be exploring the ocean worlds that orbit Jupiter and Saturn?

A: I'm heavily involved in one mission—the Europa Clipper. Extant life there is much more likely today than on the surface of Mars. On the other hand, they're further away, and Europa in particular is in a harsh radiation environment. I think we should do both.

Also at The Verge.

Previously: Water on Mars
Is Anything Tough Enough to Survive On Mars?


Original Submission

Related Stories

Water on Mars

NASA reports strong evidence that liquid water exists on Mars at the present time.

Spectrographic readings from the Mars Reconnaissance Orbiter indicate the presence of hydrated salts, mostly perchlorates, in a common surface feature called "recurring slope lineae". The best conclusion at this time is that, during the summer months, salty water melts and flows downhill to form the lineae, then freezes during the winter.

This water may, however, be unable to support life. The salt content is incredibly high, which lowers the freezing point and allows it to melt at -23° Celsius. An Antarctic lake with similarly low temperature and high salinity is lifeless, so scientists are conservative in stating the effects this has on the potential for life on Mars.

RSLs have long been considered weak evidence for water on Mars. Current Mars rovers are prohibited from examining them, as they were not sufficiently sanitized before launch, and Earth microbes may have hitched a ride. While the Mars 2020 mission will also not be completely sterilized, I expect probes after that will be, to examine these formations up close.


Original Submission

Is Anything Tough Enough to Survive On Mars? 15 comments

The answer, strangely, is not "Chuck Norris":

Two recent publications suggest that life, in the form of ancient, simple organisms called methanogens, could survive the harsh conditions found near the surface of Mars, and deep in its soils. Using methanogens to test for survivability is particularly relevant because scientists have detected their byproduct, methane, in the Martian atmosphere. On Earth, methane is strongly associated with organic matter, though there are non-organic sources of the gas, including volcanic eruptions.

Scientists aren't yet sure what the presence of Martian methane means. But one possibility is that tenacious life flourishes on Mars despite the rocky soil, thin atmosphere and scarcity of liquid water.

"We consider methanogens ideal candidates for possible life on Mars because they are anaerobic, and non-photosynthetic, meaning that they could exist in the subsurface," said Rebecca Mickol, a Ph.D. candidate at the Arkansas Center for Space and Planetary Science. "Just a few millimeters of Martian regolith is enough to protect the organisms from the dangerous UV and cosmic radiation that hits the surface. Additionally, methane has been detected in the Martian atmosphere, via multiple space-based and ground-based sources, including the Martian rover, Curiosity. Although these findings are still controversial, the presence of methane on Mars is particularly exciting because most methane on Earth is biological in origin."


Original Submission

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  • (Score: 2) by Snotnose on Thursday November 23 2017, @11:21PM (1 child)

    by Snotnose (1623) on Thursday November 23 2017, @11:21PM (#600868)

    He doesn't think the individual sand particles can act on their own, and for the greater good he is introducing a plan to Congress to get NASA to some a couple Cat bulldozers to Mars to level the playing field.

    --
    Why shouldn't we judge a book by it's cover? It's got the author, title, and a summary of what the book's about.
    • (Score: 2) by realDonaldTrump on Friday November 24 2017, @02:00AM

      by realDonaldTrump (6614) on Friday November 24 2017, @02:00AM (#600899) Homepage Journal

      If you don’t drink and you don’t do drugs, your children are going to have a tremendously enhanced chance of really being successful and having a good life. The world is so tough and it is so competitive that you can’t put yourself, as a child, or even as a parent, if you want that child to be successful, at a disadvantage of letting them drink or letting them take drugs because it is not going to work. They are going to be at a tremendous disadvantage and ultimately they may not recover.

      Happy #NationalDayofThanksgiving [twitter.com]!

  • (Score: 3, Interesting) by Runaway1956 on Thursday November 23 2017, @11:43PM (2 children)

    by Runaway1956 (2926) Subscriber Badge on Thursday November 23 2017, @11:43PM (#600876) Journal

    This is science? FFS, researchers allow their own limited imaginations to color their view, and thus, their findings? This guy saw something that sorta resembles something he's seen on earth, and jumped to a conclusion. "That's water erorsion!" Except - there is little to no water to cause erosion.

    Give him credit. He's backing off from that assertion. Hey, people, there may be no water on Mars. That erosion we saw could be caused by sand in the wind.

    • (Score: 0) by Anonymous Coward on Friday November 24 2017, @01:26AM

      by Anonymous Coward on Friday November 24 2017, @01:26AM (#600891)

      First, this:

      That erosion we saw could be caused by sand in the wind.

      And then this:

      researchers allow their own limited imaginations to color their view, and thus, their findings? This guy saw something that sorta resembles something he's seen on earth, and jumped to a conclusion.

      Yeah, right, Runaway! Do you call this science?

    • (Score: 2) by FatPhil on Friday November 24 2017, @03:45PM

      by FatPhil (863) <pc-soylentNO@SPAMasdf.fi> on Friday November 24 2017, @03:45PM (#601060) Homepage
      I do remember being a bit of a skeptimist[*] on hearing the initial announcement. Particularly suspicious was that we only noticed the before and the after, but never the thing that was apparently responsible for the change in state. We noticed the tooth, we noticed the coin in the morning, therefore there must be a tooth fairy.

      Personally, I think the Mars rovers have been two of the best spacey things NASA's done in recent years, and I'm happy to pay lip-service supporting sending more r2d2s up there to sniff around the relevant areas, there's plenty to discover even if it's not water. (Alas, I can't pay anything but lip-service, not being a US tax payer. Maybe ESA, India, or China can pick up the baton?)

      [* shut up, I love the word]
      --
      Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
  • (Score: 0) by Anonymous Coward on Friday November 24 2017, @01:34AM (5 children)

    by Anonymous Coward on Friday November 24 2017, @01:34AM (#600893)

    It's inconceivable to me that there aren't places where there's liquid water today within Mars. If there was ever life on Mars—that originated somewhere—why wouldn't there still be life today in these underground pockets?

    WTF does that even mean? Conman jackass.

    • (Score: 2) by qzm on Friday November 24 2017, @02:52AM

      by qzm (3260) on Friday November 24 2017, @02:52AM (#600904)

      Its called 'scientific inquiry', its also called 'I want to keep getting funding'.
      Its also hardly newsworthy, and reporting it is rather... tacky?

    • (Score: 0) by Anonymous Coward on Friday November 24 2017, @03:38AM

      by Anonymous Coward on Friday November 24 2017, @03:38AM (#600914)

      Take a chill pill.

    • (Score: 1) by khallow on Friday November 24 2017, @06:54AM (2 children)

      by khallow (3766) Subscriber Badge on Friday November 24 2017, @06:54AM (#600973) Journal
      In other words, he is of the opinion that if there was life on Mars in the past, then it probably still is due to underground water. On Earth, if our atmosphere got wrecked to the point where no life could exist right on the surface, bacterial life could still exist underground (some which extends miles underneath) since it's not dependent on atmosphere to live.
      • (Score: 0) by Anonymous Coward on Friday November 24 2017, @04:59PM (1 child)

        by Anonymous Coward on Friday November 24 2017, @04:59PM (#601075)

        The first sentence states waterless Mars is inconceivable to him. Just after an article came out suggesting the erosion pattern doesn't mean water presence. Nor is there good evidence there was/is lifeform on Mars. These notions don't mash with each other.

        • (Score: 1) by khallow on Friday November 24 2017, @05:18PM

          by khallow (3766) Subscriber Badge on Friday November 24 2017, @05:18PM (#601079) Journal

          The first sentence states waterless Mars is inconceivable to him.

          We already know there's considerable water ice [wikipedia.org] on Mars. And the interior would be warmer. We have evidence of volcanism and we know the interior of Mars would still be warm due to heat of formation (from slamming all that mass together 4 billion years ago) and radioactive decay of things like uranium and thorium in the interior. So liquid water under the surface isn't a stretch, we just haven't seen it yet.

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