New study says recurring dark streaks on Mars are from flowing sand, not water


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The uncertainty of science: A new study has concluded that the recurring dark streaks on Martian slopes are caused not from flowing seeps of water but from small sand avalanches.

Continuing examination of these still-perplexing seasonal dark streaks with a powerful camera on NASA’s Mars Reconnaissance Orbiter (MRO) shows they exist only on slopes steep enough for dry grains to descend the way they do on faces of active dunes.

The findings published today in Nature Geoscience argue against the presence of enough liquid water for microbial life to thrive at these sites. However, exactly how these numerous flows begin and gradually grow has not yet been explained. Authors of the report propose possibilities that include involvement of small amounts of water, indicated by detection of hydrated salts observed at some of the flow sites.

The results do not exclude the possibility that water plays a part, but do suggest it plays a much smaller part, or none at all.

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7 comments

  • wayne

    Red Planet Mars (1952)
    https://youtu.be/91cIlQQaQEQ
    (4:25)

  • Max

    I have a hypothesis, OK… a wild guess.

    If the earth pass through an interstellar gas cloud, like the one between us and the center of our own galaxy, the elements in that cloud would freeze to the planets and moons as it diminishes the sunlight creating an ice age for all of the gravitational bodies in our solar system.
    On the earth, the hydrogen gases are converted into water collapsing the atmosphere covering the earth in water (ice). The evidence is considerable.

    On Mars, this gas cloud would collect to the cold surface, thickening the atmosphere, creating great storms that would blow sand over the top of ice deposits which would remain frozen for millions of years until wind moved the dunes again. Exposing, melting, evaporating allowing the sand, which has been stable, to become unstable all along the edge and collapse.
    In areas that have undercut the ice, the carbon dioxide chunks will tumble sliding down the slope leaving different tracks.

  • wayne

    Max-
    I’d hold the formation of the Sun (and solar system) as a major contributing series-of-events, to our early atmosphere & formation of liquid water. (but, I’m way fuzzy on the formation of our atmosphere, and our water.)
    I do know oxygen is very reactive and was not always present in our early atmosphere and basically toxic to a wide swath of biotic stuff.

    Anyway… interesting stuff Max, always enjoy your speculations!

    Q: What is the “natural slope” of Martian “sand,” in the gravity of Mars?
    We have a lot of ‘beach sand,” and glacial-till in Michigan, and I know how that behaves in general, but I am fuzzy on how “sand” behaves on Mars.

    –Aren’t these the same events associated with carbon dioxide sublimation & movement?

  • LocalFluff

    Max,
    My username Local Fluff is an astronomical term. The local fluff is star stuff puffed out by the newly formed, and thus actively “puffing” (and supernoving), star cluster in the nearby Scorpius-Centaurus Association 400 ly away.

    This fluff puff that is passing by the Sun right now, is doing so in the much larger and less dense Local Bubble, which is a part of the local Chimney. Large stars explode young and small stars are also shedding gas when they are young. When conditions are such in an galactic arm that cold gas form many stars in a “burst”, such emptied bubbles are formed from the pressure, and even turn into chimneys or fountains that throw gas and dust out of the galactic plain from where it falls back again somewhere else on the disk. These environments are transient, the Sun has most likely passed through many bubbles and denser regions. It makes an orbit around the Milky Way every 250 million years, the dinosaurs lived 50 000 ly from here.

    The idea that the Solar System passing through dust clouds causes the ice ages seems to have been popular in the 1930-40s. But there seems to be no substantial dust clouds in our orbit around the Milky Way. Although we are inside of an ejected star stuff fluff puff now, even that is less dense than the average galactic interstellar medium. If we would’ve been inside of a star bursting region, like the Scorpius-Centaurus Association, then we would’ve seen firework from star jets and supernova. Luckily, they are quite short lived and quit local.
    http://www.solstation.com/x-objects/chimney.htm

  • Calvin G Dodge

    This doesn’t surprise me. Given that water evaporates almost instantly in that near-vacuum, I found it very unlikely that such a frequent occurrence was sustainable over millions of years.

  • LocalFluff

    Calvin G Dodge
    But water IS liquid on Mars’ surface! NASA’s near polar Phoenix lander imaged water drops. Salty brine water as it is understood. At the lowest altitude during the best season, even pure liquid water may just barely float on Mars surface.

    With just a little extra pressure, by being under a little dust layer, brine could quite plausibly generate such stripes on the surface. There are underground glaciers on mars, maybe ancient polar caps that have been covered by dust since Mars’ rotational axis tipped over to create new poles. The volatiles (CO2 and H2O) at the poles of Mars are seasonal quite active. Mars has strong seasons because of its eccentric orbit.

    So it was not a very far fetched idea, AFAIK. But exotic worlds are transformed by exotic processes.
    https://www.space.com/6394-phoenix-mars-lander-liquid-water-scientists.html

  • Max

    Calvin:
    My thoughts exactly, most of mars atmospheric pressure is right at the point where solid water turns to a vapor. (I know this from reading how to dry freeze food.) The only place on Mars that has enough air pressure to have liquid water is the deepest (4.4 miles) impact basin “Hellas Planitia”.
    The pictures make it look like it’s full of cement fine dust. There could be a frozen lake underneath, or perhaps a long lost civilization some sci-fi books speculate… It is a death trap for a rover, that’s why I encourage a low altitude balloon drop. A drill platform to be lowered to the surface to test stability, take samples or do soundings and test if it is as dangerous as it looks. On command, the balloon will refill with helium and move to a new test site.

    Wayne said:
    “I am fuzzy on the formation of our atmosphere and water”
    How it formed depends on what book you read, or what school you attended. There are some points in which they all agree. That our atmosphere was once carbon dioxide with small amounts of nitrogen. Much like our current Venus.
    Life happened. Life ate the CO2 to form its body, released the oxygen as feces which was/is poison. Evolved a shell made of calcium to protect itself from the elements, acids (H4O2) that terraforming was creating in an oxygen rich atmosphere as the carbon dioxide begin to disappear. Picture the early earth as a mostly smooth ball covered in calcium carbonate with water beginning to cover much of the surface.
    Then came the giant impact that set the world on fire. Current theory is a Mars sized object colliding with the earth. (The moon, in my opinion, exactly fits the equation for this impact. It’s missing the crust exposing the mantle on it’s near side. The hotter than super nova temperatures created on impact would explain the heavy metals and short-lived radioactive materials on the surface of our world. The isotopes of the moon rocks are exactly the same as our continents which are floating on top of a layer of calcium carbonate which not only causes Continental drift… The heat and pressure is converting the ancient atmosphere of limestone to oil and gas fueling short lived volcanoes to recycle the carbon dioxide back into the atmosphere. This is why oil is called fossil fuel).
    There is far too much nitrogen than the standard model allows for. (the decomposition of radioactive isotopes) there is also too much water then any model can account for. You have heard of comets of ice colliding, bringing water to earth. Perhaps. There is more evidence for methane and ammonia that is common throughout our solar system which would oxidize with our atmosphere making water here… It is the only place we have seen that has free oxygen a plenty. (Silicon dioxide makes up nearly half of our crust, oceans by mass is mostly oxygen, our atmosphere has 18% oxygen.)
    Solar wind is mostly hydrogen and helium. When heavier gases from under the sun’s surface are thrown at us in a chronal mass ejection, our magnetic field captures millions/billions of tons of the ionized gas where it is oxidized in a spectacular display of northern lights. (The chemical make up of the heavier gases is in the color of the storm) hydrogen rich gases are converted into water and carbon dioxide, rising ocean levels and adding nitrogen to the thickness of our atmosphere while removing oxygen.

    Local Fluff:
    You have provided useful information and proof that our little solar system is not safe, way out here in the spiral arm of the galaxy.
    Your article indicates that most of the local fluff is loose cold sodium like ions that do not hold much of an electrical static charge unlike the fresh hot gases that come from a supernova which are super charged with an electrical field that holds them together with the strongest force in the universe… Magnetism.
    The chimney effect will funnel gases in the path of least resistance or hold them together to form new stars like what appears to be happening in the Pleiades Star cluster.
    If such an event happen to us, Earth would experience a drastic climate change as has been evidence from what we know of the distant past.
    A thick, water laden atmosphere would have a uniform temperature. Hi atmospheric pressure would force excess carbon dioxide to mostly exist as a liquid.
    A gas cloud from deep space would be attracted to all the celestial bodies (like Mars) coating them with ice. Adding mass and volume to the gas giants. I can only speculate if the solar wind would push it away or if great quantities of mass would snuff out the chromosphere pouring into our Sun creating violent reactions.
    If the gas conducts electricity, giant electrical arcs from the sun would be extended far out into space equalizing the potential charge with every body it touches.

    On earth, the thick atmosphere would collapse as the gases convert into water filling the oceans 400 feet higher, releasing earths heat in the process resulting in a series of ice ages. Stars, for the first time, would be visible and the nights would be freezing cold… The days would be scorching hot creating large atmospheric storms. Only the heartiest of species would survive.

    As you probably noticed, I take what is possible and connect it with actual facts that is provable. Like a jig saw puzzle, I try to put the pieces where they fit best best. There is a lot of pieces missing from this puzzle.

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