
Suddenly, It Seems, Water Is Everywhere in Solar System - brkumar
http://www.nytimes.com/2015/03/13/science/space/suddenly-it-seems-water-is-everywhere-in-solar-system.html
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vortico
Everywhere except California apparantly.
[https://news.ycombinator.com/item?id=9198260](https://news.ycombinator.com/item?id=9198260)

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moreproductive
I came here to post this exact post. Bravo. And sad face (I live in LA)

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myblake
Heh also came to say the same thing. On reddit it would have obviously
happened asap but I thought maybe there's less snarky humor on HN. Guess we
couldn't resist this one though.

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Mahn
Does anyone else think NASA should reconsider their plans for a manned mission
to Mars? With Europe, Ceres, Enceladus, Ganymede and many more promising moons
out there it seems kind of a waste to spend time, effort and capital in Mars
now.

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Symmetry
Europa is a lot further away than Mars [1]. Every extra 4600 m/s of delta V in
the mission means another factor of e in the ratio of initial to payload mass.
At least until we develop better high efficiency rockets.

[1] [http://i.imgur.com/AAGJvD1.png](http://i.imgur.com/AAGJvD1.png)

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throwaway_yy2Di
In practice, the ΔV differences are actually way smaller than that chart
suggests. Those figures are for direct transfers (per the legend). But if you
allow indirect trajectories with gravity assists [0], that makes things
drastically cheaper. To intercept Jupiter, you can steal much of the needed ΔV
from flybys of the inner planets (at the tradeoff of _time_ , waiting to go
around the sun multiple times). And maneuvering within Jupiter's gravity well
can be practically free, by flybys of the Galilean moons. The map tells you
8,890 m/s to intercept Europa, which would be _horrifying_ , but none of that
actually needs to be propulsion.

[0]
[https://en.wikipedia.org/wiki/Gravity_assist](https://en.wikipedia.org/wiki/Gravity_assist)

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pwnna
Keep in mind, for a human mission, you want to minimize time, rather than
deltaV. Gravity assists will take a lot of time, as you spend a lot of time
waiting for the encounter.

Furthermore, that chart is likely computed via a direct Hohmann transfer,
which is one of the most efficient transfer maneuvers available. It also will
take a lot longer.

For practical human travel to destinations farther way, you need to perform
the so called "star wars maneuver", which is going essentially from A to B in
a more or less straight line, which will cost a LOT of delta V.

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buss
> Keep in mind, for a human mission, you want to minimize time, rather than
> deltaV. Gravity assists will take a lot of time, as you spend a lot of time
> waiting for the encounter.

True, but we could throw the big ship with all the supplies into a flight path
that gains a lot of momentum around the inner planets and intercept it with a
much smaller craft only loaded with enough fuel to get the astronauts to the
transit ship (and back, if necessary).

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PhoenixWright
Growing up this was a huge question that nobody knew the answer to. I don't
remember the first discovery of water but I do remember reading one after
another water finding. Back then water = life and if we found water it was
very likely we would find some form of life. I've already read articles
talking about microbial life but I think we will soon discover a variety of
living forms.

That being said I don't think our solar system contains a more advanced being
than humans. But what life, in some form, demonstrates is that it is possible,
in some place very far away, there are living beings as advanced or more than
we are. I would really love to be alive to meet them.

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bostonpete
> That being said I don't think our solar system contains a more advanced
> being than humans.

I can't imagine there would be any real debate over that point.

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gulpahum
Do those moons really have a flowing ocean under the icy surface or is it
water trapped in rocks?

Earth has a huge "ocean" deep in its mantle, but it's inside rocks.
[http://www.livescience.com/1312-huge-ocean-discovered-
earth....](http://www.livescience.com/1312-huge-ocean-discovered-earth.html)

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kchangnyt
Yes, these are flowing oceans. On Ganymede, it's an ocean between two layers
of ice. On Enceladus, it's water below an icy crust and on top of a rocky
core.

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bladedtoys
Has anyone thought much about an (admittedly near impossible) probe to burrow
and submarine around in the oceans of some of the juicier Galilean and
Saturnian moons?

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V-2
For what it's worth, there's quite a decent s-f movie "Europa Report" about a
manned mission to the Jupiter's moon.

It avoids most genre cliches, apart from the very ending maybe.

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xpinguin
_> It avoids most genre cliches, apart from the very ending maybe._

Yeah, by being fully made of those. [SPOILER ALERT]

* lack of crew psychological cross-matching

* some ludicrously exoggerated hydrazine drama

* chloroplast-equipped organisms in the environment which ambient light spectrum is _slightly_ inclined towards gamma radiation (not to mention the meat-packed space vessel itself, brightly shined up by very same light)

* _one_ central computer with sole purpose to be heroically repaired on the _outer_ shell of the vessel (you see, no EVA - no drama)

* (mentioned ending) transferring at least tens of gigabytes from Europe to Earth in a matter of seconds (via that special hero-driven central computer) despite being unable to establish uplink for past several months already due to the broken trasmitter (of course, unreserved)

\---

Well, I understand that this is just a movie, but look, why not to put it in
agreement with some common sense?

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V-2
Honestly, I can't see how these are "genre cliches"

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xpinguin
Disorganized team/crew of what first have seemed to appear as "professionals",
imho, is a curse of most sci-fi movies (I could hardly recall any movie with
more than one actor, where characters won't behave like a bunch of strangers
gathered together under some unfortunate circumstances).

Exoggerated drama (i.e. dramatic action out of nothing or due the course of
highly regulated procedures (eg. EVA)) is harder to evaluate: sometimes that
drama looks quite plausible. Nevertheless, action sci-fi without some sort of
team member sacrificion/unexpected death is hard to imagine, at least for me.
Hell, it is not even specific to sci-fi: just take a look into any action
movie out there - pretty high chances to become a witness of the dramatic
death.

Very frivolous treatment of the laws of physics in general. I am pointing out
that instantaneous information transmission specifically. Well, pretty much of
cliche either, isn't it?

Stupid reasons for "heroicity". Are you a script writer in a search for the
rationale to balance around the case of dramatic death of one or more
characters? Director struggling with producers demand for fancy attention-
binding activity you might be. What to do? Easy! Just place some important
peace of equipment in a morbid place and there you go - engineering have been
favored out by thrill.

Life. Remember that in "Babylon 5" most of aliens were anthropomorphic? Well,
90th there were, no fancy CG, and, besides, _convergention_ one may say,
right? Second decade of XXI century, Wikipedia is here and accessible in a
matter of keystrokes. Why not chemothrophs, why?! Although, phototrophs could
be plausible even in a shady world, _convergention_ one may say...

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bane
It's not too much of a surprise, both elements that go into water are
plentiful and not particularly heavy, and both want to bind to something.

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T-hawk
It's surprising (water is perceived to be scarce) because:

\- oxygen just as readily binds to everything else, to form metal oxides (the
well-known rust on Mars) or silicates (rock) or just CO2 (Venus)

\- hydrogen is so light it readily escapes into space from anything smaller
than Earth

\- H2O as solid ice is common anyway, but not as liquid water, which is more
relevant for potential habitability and life. The conditions for the liquid
phase of water are a remarkably narrow area on the phase diagram. That we have
found in few locations, and it's news when a new such place is discovered.

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crystaln
If there is both vapor and ice, there must always be at least some water. If
water is plentiful, space is cold, and planets are hot, liquid water should be
common, regardless of how narrow the temperature conditions for it are. All
temperatures from cold space to molten rock are well represented on planets.

~~~
rthomas6
That's not true at all. It depends on the pressure.

[http://d32ogoqmya1dw8.cloudfront.net/images/research_educati...](http://d32ogoqmya1dw8.cloudfront.net/images/research_education/equilibria/h2o_phase_diagram_-
_color.v2.jpg)

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crystaln
Excuse me. As long as the pressure is at least 0.006 atm. Is that what your
point is?

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rthomas6
Yes. The pressure of space is not sufficient for liquid water, regardless of
how hot or cold it is. This means that regardless of how much ice or vapor
exists on separate terrestrial bodies, we cannot assume that there is liquid
somewhere in between.

Now, if there was a single planet that had both ice and vapor water, and that
planet had an atmospheric pressure of greater than 0.006 atm, then I agree
that there must be some liquid water somewhere on that planet. But ice and
vapor on a single planet with a sufficient atmosphere is a much higher bar to
clear than two totally separate places that combined have both ice and water
vapor.

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crystaln
If you actually read what I wrote, you would have understood I was referring
to water on planets. Obviously there is not likely to be liquid water in the
vacuum of space. The "space is cold" "planets are hot" might have been a
pretty sure clue that I was referring to water between a planet's hot core and
cold vacuous space.

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AnimalMuppet
Suddenly, it seems water is everwhere...

... except California.

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tempodox
Fascinating!

However, I get the cringes every time an article about space exploration uses
those atavistic units like Royal Hangnails (length), Princely Bladders
(volume), Regal Farts (speed) and Fornicating Fever (temperature) for
measurement. Hasn't the metric system arrived yet on planet USA?

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jamesmontalvo3
While I'm an American engineer who prefers working in metric, since this is a
space-related article I have to point you to this: [https://s-media-cache-
ak0.pinimg.com/736x/69/ae/01/69ae0104b...](https://s-media-cache-
ak0.pinimg.com/736x/69/ae/01/69ae0104b424acd26a0f5c4a8588befa.jpg)

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Someone1234
And I have to point to this:
[https://en.wikipedia.org/wiki/Mars_Climate_Orbiter#Cause_of_...](https://en.wikipedia.org/wiki/Mars_Climate_Orbiter#Cause_of_failure)

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RankingMember
@mitchty, I don't see how the Beagle probe relates unless parallel but
different measurement systems caused that, and I'm not seeing anything to
indicate this (but let me know if I'm missing something, I'm curious).

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aguywithamum
"The primary cause of this discrepancy was that one piece of ground software
supplied by Lockheed Martin produced results in a United States customary unit
('American'), contrary to its Software Interface Specification (SIS), while a
second system, supplied by NASA, that used those results expected them to be
in metric units, in accord with the SIS."

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RankingMember
That's in reference to the Beagle 2?

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aguywithamum
Yeah, that's in reference to the failure of Beagle 2. It's on the page that
was linked by Someone1234
([https://en.wikipedia.org/wiki/Mars_Climate_Orbiter#Cause_of_...](https://en.wikipedia.org/wiki/Mars_Climate_Orbiter#Cause_of_failure)).

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TorKlingberg
The Beagle 2 and Mars Climate Orbiter are not the same thing. It is unknown
why Beagle 2 failed and there is no reason to believe it was due to any unit
mismatch. It may be that two of the solar panels failed to deploy.

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warkdarrior
It's well known that the metric solar panels failed to deploy. The imperial
solar panels opened successfully, but that did not generate enough electricity
to keep going.

