

NASA Rover Finds Old Streambed on Martian Surface  - Sodaware
http://www.jpl.nasa.gov/news/news.php?release=2012-305

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jpxxx
A quick Mars timeline:

Mars was formed around the time Earth was, but it was blessed with only 11% of
Earth's mass and less than 40% of Earth's gravity field. Shortly after cooling
solid, its "Noachian Era" was similar to proto-earth: warm, a thick
atmosphere, plenty of liquid water on the surface, and probably a significant
magnetic field.

But this era was still during the era of the Late Heavy Bombardment, a time in
which the last dregs of the solar system were still settling out. Large
asteroids still pounded the planets with regularity.

Unlike Earth, Mars had trouble maintaining its liquid iron magnetic field.
Since it's much smaller, it cooled and thus congealed faster. And there's
growing evidence that asteroid impacts were able to drive enough heat beneath
the surface that interior convection was quelled, leading to a fragmented
magnetic field.

Without an adequate magnetic field to deflect solar wind, the atmosphere was
prone to shedding off pieces of itself into space. This was amplified by the
lower gravity which meant holding on to lightweight gasses was even harder.

Over time, Mars cooled to the point where the major forms of tectonics ceased.
The water locked up beneath the ground, rusted out pulverized basalt dust from
the asteroid impacts, and frizzled in the radiation-baked atmosphere, floating
off.

The seas and lakes dried, the rain stopped, and that... was that.

Three billion years later, we arrive on the scene and find out we have a
little sibling. Then we send robots. We hope to find life, or evidence that it
once lived. Characterizing how water worked in the Martian past is a part of
answering that question.

~~~
samspot
I really dislike when scientific theory is presented this way. You imply too
much when instead of using phrasings like "We have evidence that suggest X"
you say "X happened."

> The seas and lakes dried, the rain stopped, and that... was that.

We think there was water on mars, therefore it is true. Is it too much to put
a disclaimer somewhere that explains this is the current consensus but we have
more to learn? The truth is that this story is riddled with assumptions, and
readers need to know that.

~~~
jpxxx
I'm not a scientist, just a pithatician. I have no formal or informal
education in this matter and my understanding is strictly derived from
pleasure reading. But I think there's enough evidence to back up this general
narrative without throwing asterisks everywhere.

~~~
domdelimar
What do you mean by "pithatician"? Really, absolutely no results searching the
web or trying to translate it. O_o

~~~
001sky
I'm not a "pithatician", but methinks it has something to do with the word
"pith" and its Variant "pithy". A quick google of said terms yielded the
following points of note:

 _Pith is the central idea or essence of something. If you’re in danger, you
could exclaim, “I would greatly appreciate it if someone would provide
assistance.” Or, you could get right to the pith of your point by shouting,
“Help!”_

Following along this line of inquiry, one is led to consider the possibility
(however remote) of this being an example of near-humour. Possibly of the
genus: Pun, species: indirect. So, if one were to dress this up, it is perhaps
alluded to as a Punnus Indirrectus.

Or, maybe Not. =D

~~~
jpxxx
Ding ding ding! A stuffed animal for the man. :]

~~~
domdelimar
Thank you @001sky for explaining and @jpxxx for confirming. :)

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jpxxx
Not to burst anyone's bubble, but this is not the staggering news it's being
made out to be. It is good foundational geology, yes, but water has
essentially been confirmed for years now.

The story of Mars in short: flop planet, can't hydrosphere.

There is extremely strong evidence that in the very early years Mars was
capable of holding on to a great deal of water: Enough to cover the Southern
Hemisphere. The streambed seen here is from that time.

That downer is that this was over 3 billion years ago. Through a variety of
processes and for a number of reasons most of Mars' water was lost to space or
trapped underground.

The billion-dollar question that would be epic to answer: Did Mars develop Or
acquire life during the time it had liquid water on the surface and if so is
there any trace of it left, alive or dead?

~~~
bootload
_"... but water has essentially been confirmed for years now. ..."_

From the article, _"... This is the first time we're actually seeing water-
transported gravel on Mars. This is a transition from speculation about the
size of streambed material to direct observation of it ..."_

~~~
jpxxx
Yes, it is good foundational geology being reported upon.

What's cool about that is that it allows you to directly calculate how much
water flow was involved in moving this gravel (taking in to account the much
lower Martian gravity), you can use the pattern in which the gravel deposited
itself to determine what direction the flow was going, and more.

------
bootload
_"... NASA's Curiosity rover mission has found evidence a stream once ran
vigorously across the area on Mars where the rover is driving. There is
earlier evidence for the presence of water on Mars, but this evidence --
images of rocks containing ancient streambed gravels -- is the first of its
kind ..."_

Why isn't this front page, the implications are staggering.

~~~
tisme
Part of the reason may be that NASA has been crying wolf before. The 'arsenic
life' announcement wasn't that long in the past. So people may be a bit wary
until the images have been independently analysed.

~~~
bootload
_"... So people may be a bit wary until the images have been independently
analysed...."_

Good point. The theory of a flowing river should support all types of evidence
at large & small scale: alluvial fans,

 _"... The imagery shows an alluvial fan of material washed down from the rim,
streaked by many apparent channels, sitting uphill of the new finds. ..."_

to pebbles and rate of flow of liquids,

 _"... From the size of gravels it carried, we can interpret the water was
moving about 3 feet per second, with a depth somewhere between ankle and hip
deep... This is the first time we're actually seeing water-transported gravel
on Mars. This is a transition from speculation about the size of streambed
material to direct observation of it. ..."_

All directly observable evidence, each piece confirming the conclusion.

------
Zenst
Out of the set of pictures I find this one the most intriging
[http://www.nasa.gov/mission_pages/msl/multimedia/pia16189.ht...](http://www.nasa.gov/mission_pages/msl/multimedia/pia16189.html)

The cemented section on the mars side is in itself most interesting I find and
yet seem unable to state why. Wonderous stuff indeed.

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wamatt
_"From the size of gravels it carried, we can interpret the water was moving
about 3 feet per second, with a depth somewhere between ankle and hip deep,"
said Curiosity science co-investigator William Dietrich of the University of
California, Berkeley._

Out of interest, how do we know it was water, and not some other liquid?

~~~
jpxxx
A good piece of evidence is that the dust of Mars is significantly composed of
'goethite', essentially hydrated iron rust. There's an awful lot of dust, and
if you do the work backwards you can get a decent idea of how much water it
took to make it happen.

Furthermore, most liquids found at reasonable temperatures aren't all that
voluminous, and a number of the minerals scanned and inspected on Mars show
evidence of water contact.

Basically, there's not much else it could be. :) That said there's some really
cool theorizing on underground carbon dioxide flows that might explain some
washouts seen later in Mars's life.

<http://en.wikipedia.org/wiki/Goethite>

~~~
bootload
_"... A good piece of evidence is that the dust of Mars is significantly
composed of 'goethite' ..."_

you mean these? _"small spherical hematite balls, dubbed ‘blueberries,’"_ ~
[http://www.lifescientist.com.au/article/436306/iron_blueberr...](http://www.lifescientist.com.au/article/436306/iron_blueberries_may_sign_microbial_life_mars/)
Goethite: learn something new every day.

~~~
jpxxx
Almost! The blueberries are hematite, Fe2O3, an iron oxide. Goethite is
FeO(OH), an iron oxyhydroxide. Both strongly indicate water went in to making
them but the blueberries imply they were submerged in water whereas goethite
doesn't necessary require anything but water vapor.

------
DigitalSea
The real question is where did the water go and does it still exist somewhere
on Mars? Finding a little bit of ice or water is one thing, finding an old
streambed is another — but potentially finding an underwater ocean/ecosystem
filled to the brim with undiscovered organisms makes me excited not only from
a study of different organisms perspective but perhaps because the key to
curing diseases that plague Earth might be found on Mars not to mention
unlocking other discoveries like how to live longer and even more exciting
finding organisms that don't age and have been alive since Mars was created.

My mind is teeming with excitement of the possibilities, is anyone else as
excited as me?

~~~
waterlesscloud
I almost hope no traces of life are found.

If traces of life are found, however distant in the past, it seems quite
likely that any Mars colony or even exploration would be delayed by decades,
if not longer. Preservationists would be against any interaction whatsoever.

~~~
andrewflnr
When have preservationists ever had their way, though? Granted, life on Mars
would be a unique case, but I'm not sure you need to worry about them.

~~~
Almaviva
As someone who would take such a preservationist position, I think this is my
best argument: It is morally inconsistent to think that super-intelligent life
should leave us intact if we were found, and at the same time be willing to
interfere with vastly less advanced life, for our own gain.

~~~
kamaal
If we aren't going to mars to destroy life on mars. Why should we expect that
the super intelligent species will try to destroy us?

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teeja
No they didn't find a "streambed". They found a bunch of clasts, with pebbles
that wind couldn't move. Perhaps they were moved by something solid rather
than liquid. Perhaps that was some kind of ice.

It's tiresome hearing of the "piling evidence" for water on Mars. Find some
damn water. Prove it by melting it then boiling it on camera in a container
with a thermometer.

