
Previous Evidence of Water on Mars Now Identified as Grainflows - lnguyen
https://www.usgs.gov/news/previous-evidence-water-mars-now-identified-grainflows
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kamac
> This new research finds that these RSL features are flows of granular
> material and thus, align with the long-standing hypothesis that the surface
> of Mars lacks flowing water. Small amounts of water could still be involved
> in their initiation in some fashion, as hydrated minerals have been detected
> at some RSL locations. The authors conclude that liquid on present-day Mars
> may be limited to traces of dissolved moisture from the atmosphere and thin
> films of water.

So, this article says there's no water on the surface of Mars, rather than
underneath it.

Though it looks like this suggests that water beneath the surface is unlikely
to be there as well?

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drxzcl
Liquid water anyway. We know there is a lot of water ice locked into glaciers
on mountain slopes etc.

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hanoz
What was it that made them think it was water rather than grain flows in the
first place, on this dry grainy planet?

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byebyetech
Did they simply went with the visual look of it? Probably did some simulations
on a computer and compared and decided its water. I would be shocked by such
low quality of Science behind it if that was the case. Extra ordinary claims
require extra ordinary evidence.

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lawlessone
Problem is if they actually suspect it's water they aren't allowed to bring
their rovers or probes anywhere near as they don't want to risk contaminating
it with Earth microorganisms.

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zachrose
And yet Elon Musk is going to build a colony?

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lawlessone
I don't believe he is bound by this, or maybe wouldn't care if he was.
[https://planetaryprotection.nasa.gov/about](https://planetaryprotection.nasa.gov/about)

[https://planetaryprotection.nasa.gov/intpolicy/](https://planetaryprotection.nasa.gov/intpolicy/)

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jbreckmckye
What would it mean for us if Mars were without water or life?

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sillysaurus3
We'll bring both.

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donatj
How do you propose we relocate any significant volume of water?

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mabbo
Science fiction has proposed a number of possible-if-difficult ways.

Comets, to start, are mostly water. If you're patient, you can redirect some
very sightly while they're in the far end of the system and have them impact
Mars. Takes a while though. Also, big boom when they arrive.

Really though, there's plenty of carbon <edit>oxygen, in the form of carbon
dioxide</edit> on Mars- you just need hydrogen. Jupiter is mostly that. With a
very large fleet of ships, you might be able to bring some to Mars. Solar
sails might help keep costs low, and ideally they're fully autonomous. Heck,
if that works, you'd probably want to start doing the same trick and pouring
hydrogen into Venus while taking away CO2.

I'm sure there's other ways too. Plus, we know there is some water on Mars
already. If we can use it carefully, reuse exhaustively, it could sustain a
large population.

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ams6110
You need oxygen, not carbon, to make water.

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mabbo
Ah, teaches me for trying to write before my morning caffeine.

Oxygen. Oxygen is what Mars already has, in the form of CO2, carbon dioxide.

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baldfat
Is it like the Sailing Stones we have observed in the desert but with grains
of sand?

[https://en.wikipedia.org/wiki/Sailing_stones](https://en.wikipedia.org/wiki/Sailing_stones)

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japhyr
Those rocks move because they're carried by thin ice sheets every once in a
while:

> rocks move when large ice sheets a few millimeters thick floating in an
> ephemeral winter pond start to break up during sunny days. These thin
> floating ice panels, frozen during cold winter nights, are driven by wind
> and shove rocks at up to 5 m/min.

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nieve
It's interesting that the release doesn't address the seasonality of the
effect unless it falls under the possible initiation handwave. Is there some
other temperature dependent effect on such flows?

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misja111
Actually the seasonality is addressed:

"The preference for warm seasons and the detection of hydrated salts are
consistent with some role for water in their initiation. However, liquid water
volumes may be small or zero, .."

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lerie82
I think it's funny they say it's a new theory that mars didnt have water.

