

Scientists find evidence of salt water flowing on Mars - petercooper
http://blog.chron.com/sciguy/2011/08/scientists-find-evidence-of-salt-water-flowing-on-mars/

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lotharbot
It's known that Mars has both ice and water vapor, and that further,
summertime temperatures are warm enough to sustain liquid water.

It's the atmosphere that makes this a bit surprising. Martian atmospheric
pressure is less than 1% that of earth in the deepest valleys, and about .006
atm on average. If you look at a phase diagram for water [0], you can see that
at .006 atm and below, water goes directly from solid to gas ("sublimation").
Even slightly above that pressure, there's only a tiny temperature range in
which liquid water will exist.

I would guess that's why they've theorized very salty water. Its lower
freezing point is going to allow for liquid water in a bigger temperature
range at typical Martian atmospheric pressures.

[0] <http://www.cims.nyu.edu/~gladish/teaching/eao/week2.html> \- top of the
page

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bfe
IIRC, Mars's global atmospheric pressure is about 25% higher in the southern
summer than in the southern winter, due to differential sublimation and
condensation of carbon dioxide, from the southern ice cap as well as from the
soil at lower latitudes, and southern hemisphere summer temperatures can range
all the way above zero celsius -- so there's quite a range of weather
conditions to which any briny water would be subjected, especially in the
southern hemisphere.

Edit to add, the Martian southern hemisphere seasons are more extreme because
the effects of its significant eccentricity and its axial tilt are additive
there, while they counteract each other to moderate the seasons in the north.

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bfe
Three cheers for the science journalism in this link. The reporter clearly
conveys the facts of the announced findings, includes images of candidate
flowing water on Mars with captions as they appear in the original paper in
the journal Science, and does a Q&A with a third party scientist who gives
knowledgable further analysis. Anyway, this is really exciting.

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pxlpshr
chron.com is Houston's major newspaper. We're cheering for more NASA funding.
:)

I love this comment:

 _The Bible didn’t say anything about god creating life on Mars._

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hugh3
Whose internet law is it that says that any sufficiently advanced idiot is
indistinguishable from a troll? Or is it that any sufficiently advanced troll
is indistinguishable from an idiot?

~~~
prawn
Poe's? <http://en.wikipedia.org/wiki/Poe%27s_law>

Comes to mind all too often when browsing comments on the net.

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doctoboggan
I think it is the general population's consensus that there is no life on
mars. With the minuscule amount of area we have explored, I think there is
ample opportunity to still discover life. Considering most landing sites have
been selected for their ease of touchdown and not possibility of life, I'd day
we still have a fair chance of finding it. This is especially true in light of
these new findings.

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MatthewPhillips
Personally I couldn't care less about finding microbial life. I want to find
animal-sized life or heavy vegetation. That Mars might house single-celled
life does nothing for my excitement.

~~~
owenmarshall
Seriously? Remember, we all started as microbes.

Finding _any_ life outside our planet would be a huge discovery; even if it's
billions of years away from growing legs, we could learn so much about life in
its early stages, which could answer some big questions about our own
evolution.

~~~
anigbrowl
True, but I'd rather send a fleet of robots over there and bottle 1000
different soil samples for later study, and then get on with terraforming the
place, perhaps by crashing a comet into it. 'But what if we contaminate this
otherwise pristine natural environment' seems to get trotted out in every
discussion of Martian exploration and is (IMHO) slowing us down.

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cryptoz
The International Space Station is the most expensive object humanity has ever
built. You think that the reason we are slow at terraforming Mars is because
we're debating about life there?! No. The reason we're slow is because it
would take millennia and incomprehensible amounts of money.

I say we land there with humans, spend a few decades checking the place out,
then begin with the terraforming.

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anigbrowl
You misunderstand me. The non-contamination argument is offered reflexively to
any proposal for work on Mars - from sending more landers to manned
exploration. It's an obstruction to funding and research, rather than to
terraforming directly - just as news like this is an encouragement.

I do not think terraforming need be terribly expensive, incidentally. We
already map a great number of asteroids and comets out of awareness that if a
sufficiently large one were to hit the Earth its impact would be devastating.
Our best understanding at present of how to deal with the possibility of such
an impact is to give the item a slight nudge that will alter its trajectory
during a non-terminal interaction with Earth's gravitational field. We have
already matched speeds with and made very close observations of asteroids, and
our observational abilities are constantly improving. So to begin the work of
terraforming Mars, I would begin looking for asteroids with large quantities
of ice (or ammonia or other appropriate compounds) that are likely to
intersect closely with Mars' orbit, and give them an encouraging nudge.

It annoys me that since the two rovers we've sent so far have worked so well,
our response is to spend years developing a New and Better Rover at great
expense, rather than launching launching a large number of rovers that use the
existing design which is already known to work, and which can be done without
any additional research whatsoever.

~~~
pyre
I was under the impression that Mars once had an atmosphere, but its lack of a
strong magnetic field means that the solar winds sweep that all away. If true,
that means that terraforming would have to involve 'jump-starting' Mars'
magnetic field, which would probably involve a great deal more difficulty.

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serichsen
It may be an indication for salt water, but there are other explanations. For
example, also sand can have something similar to fluid dynamics. You need to
take the low gravity and thin atmosphere into account and do real calculations
or simulations to gain further insights.

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petercooper
There is likely to be a lot more info shortly as there's currently a live
press conference going on (encouragingly, the BBC has interrupted its normal
news coverage to cover the entire thing).

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kevindication
FTA: "But the evidence is, so far, weak."

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th0ma5
official nasa link post <http://news.ycombinator.com/item?id=2847114>

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mukyu
<http://www.sciencemag.org/content/333/6043/740> the paper

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MatthewPhillips
Why are we wasting time looking for microorganisms on Mars when Europa might
have _fish_?

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BasDirks
Because Mars is rather close to Earth. It's going to be very exciting to see
what Europa offers us.

~~~
Sukotto

      ALL THESE WORLDS ARE YOURS EXCEPT EUROPA. ATTEMPT NO LANDING THERE.

~~~
anigbrowl
Why do people feel the need to quote this whenever Europa is mentioned?
congratulations, you have good taste in science-fiction, and now it would be
nice to move on to the science part and dispense with the fiction bit. Enough
with the space hippy act already.

~~~
stcredzero
_congratulations, you have good taste in science-fiction_

More like, congratulations, you can be conditioned like Pavlov's dog.

