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Confirmed: Water Once Flowed On Mars

Soulskill posted about a year ago | from the john-carter-spilled-his-beverage dept.

Mars 113

An anonymous reader writes "A new study based on observations last September by the Curiosity rover on Mars has confirmed that pebble-containing slabs of rock found on the Martian surface were part of an ancient streambed. The work provides some of the most definitive evidence yet that water once flowed on Mars. '[The pebbles'] smooth appearance is identical to gravels found in rivers on Earth. Rock fragments that bounce along the bottom of a stream of water will have their edges knocked off, and when these pebbles finally come to rest they will often align in a characteristic overlapping fashion. ...It is confirmation that water has played its part in sculpting not only this huge equatorial bowl but by implication many of the other landforms seen on the planet.' According to NASA, 'The stream carried the gravels at least a few miles, or kilometers, the researchers estimated. The atmosphere of modern Mars is too thin to make a sustained stream flow of water possible, though the planet holds large quantities of water ice. Several types of evidence have indicated that ancient Mars had diverse environments with liquid water. However, none but these rocks found by Curiosity could provide the type of stream flow information published this week. Curiosity's images of conglomerate rocks indicate that atmospheric conditions at Gale Crater once enabled the flow of liquid water on the Martian surface.'"

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What happened to it? (2)

gmclapp (2834681) | about a year ago | (#43874013)

I realize I could easily look it up. But, what is the leading theory as to why the planet can no longer sustain liquid water. I know that in it's current condition with low gravity and lack of atmosphere it cannot sustain liquid water... But was Mars once larger?

Re:What happened to it? (4, Informative)

averdung (2848073) | about a year ago | (#43874053)

I realize I could easily look it up. But, what is the leading theory as to why the planet can no longer sustain liquid water. I know that in it's current condition with low gravity and lack of atmosphere it cannot sustain liquid water... But was Mars once larger?

Runaway atmosphere loss is a leading candidate due to a lack of a magnetic field (and those missing gigatons of rock)...

Re:What happened to it? (2)

flayzernax (1060680) | about a year ago | (#43874243)

Atmospheric Ionization from solar wind.

Re:What happened to it? (-1)

noh8rz10 (2716597) | about a year ago | (#43874339)

i think if Mars held water before, then it can/will hold it again. it's likely underground or in the ice caps, for example. who knows? maybe mars is a dyson sphere with project genesis inside? the problem is we'll never be able to disprove this.

Re:What happened to it? (-1)

Anonymous Coward | about a year ago | (#43874573)

I think you are flaming. And possibly butt hurt. Is this a troll account?

But if you have any substantial evidence or reason to believe it might be a Dyson sphere with project genesis inside. Then feel free to share. Or make some shit up. At least come up with some creative theories or hypotheses.

Re:What happened to it? (0)

noh8rz10 (2716597) | about a year ago | (#43875145)

that's why I say who knows? it can't be disproven, so it shouldn't be discounted.

Re:What happened to it? (0, Insightful)

Anonymous Coward | about a year ago | (#43875233)

That is how religions get formed.

Re:What happened to it? (0)

Anonymous Coward | about a year ago | (#43875815)

It can be disproven. Mars is not hollow, or else it would not have the orbit that it does.

Re:What happened to it? (1)

rahultyagi (924414) | about a year ago | (#43876359)

Mars's orbit isn't a function of its mass. It only depends on Sun's mass. you could, however, make the same point using Phobos/Diemos's orbit.

Re:What happened to it? (1)

dgatwood (11270) | about a year ago | (#43878091)

IANAAP, but AFAIK, it could still be the same mass and hollow if the composition below the surface were dramatically different than the surface composition. The average density of Mars is estimated to be 3.93 grams per cc. Osmium has a density of 22.59 grams per cc. So more than four-fifths of Mars could be hollow even just using the elements we know about today.

Re:What happened to it? (0)

Anonymous Coward | about a year ago | (#43876801)

Obviously there is a black hole contained inside the dyson sphere, giving mars sufficient mass.

Re:What happened to it? (2)

fishbonz (246374) | about a year ago | (#43874685)

...maybe mars is a dyson sphere with project genesis inside? the problem is we'll never be able to disprove this.

My plan is working perfectly!

Re:What happened to it? (2)

SecurityTheatre (2427858) | about a year ago | (#43874929)

Never?

I think a small seismograph would disprove it pretty effectively...

Re:What happened to it? (0)

Anonymous Coward | about a year ago | (#43875019)

If you really want to be slick. You can tick off preexisting liquid water on mars as more evidence for the likely hood of life. Making life much less extraordinary. Further validating other data we have about potential life on mars.

Re:What happened to it? (1)

g0bshiTe (596213) | about a year ago | (#43875057)

I'll file that right in with "Hollow Earth, and Moonbases".

Beware the Moonanites.

Re:What happened to it? (0)

Anonymous Coward | about a year ago | (#43875395)

There is more to it than the lack of a magnetic field. Venus does not have a magnetic field either, it's less than half the distance of Mars to the Sun thus see 4 times the intensity of solar wind. Yet it has a very robust and dense atmosphere.

Re:What happened to it? (1)

Anonymous Coward | about a year ago | (#43876591)

The magnetic field has less to do with keeping the atmosphere in and more to do with the rate at which the atmosphere is stripped away by solar radiation.

A recent article comparing the radiation levels shows that atmosphere is lost 10 times faster on Mars than Earth. So if anything Mars is showing us what Earth will be like in the future given no greenhouse effect.

The atmosphere of Venus has a run-away greenhouse effect, and is likely why it has an atmosphere and Mars pretty much doesn't. Likewise the composition of the atmosphere's are different. Venus is basically an acid bath in CO2. Earth and Mars has O2 CO2 N2 components. We won't know til 2016 what Venus's atmosphere/magnetosphere is like. Another possibility is that Venus might have Volcanic activity that is driving the greenhouse effect (and that is based on how earth volcanoes are active, a byproduct of tectonic activity) Mars might not have any active volcanoes or may not even have any tectonic activity at all.

What is a safe assumption, is that not all greenhouse gas is bad. Even though we may try to reduce our production of CO2, that is purely to prevent three scenarios:
1. Reduction of breathable air (O2) - with animals and humans not adapting fast enough (or overpopulation/combustion driving down the O2 available)
2. Increase in Sea levels/water vapor due to warming that impacts human settlements. (At the rate we're going the Eastern US will be under water by 2300, if the water doesn't vaporize first)
3. Prevent acidification of the atmosphere and water

Unchecked, eventually the oceans will become so acidic that only jellyfish will be able to live in it. The atmosphere will increase in CO2 to the point where the oceans will boil off, and then we will end up like Mars.

Like if you look at the big picture, Mars has little to no magnetic field. The magnetic field on Earth is due to the dynamo action with the iron core. So either Mar's has a smaller iron core, or it's action is so much slower that the field has dissipated.

Re:What happened to it? (1)

MiniMike (234881) | about a year ago | (#43875523)

Question about the atmosphere knocked off of Mars- some of it would probably not achieve escape velocity, and eventually fall back to Mars. But some would be moving fast enough to escape. Are there any theories as to where this mass went? Might sizable portions have wound up on Earth or Jupiter? The asteroid belt? Or is most of it still orbiting independently? Unless it achieves solar escape velocity (34.1 km/s at Mars) it seems like it would eventually fall towards the sun unless it hits a planet/moon/another solar wind/anything else. It has to go somewhere- has anyone looked into where?

Re:What happened to it? (1)

amaurea (2900163) | about a year ago | (#43877109)

The lack of a magnetic field might indeed be the explanation, but right now the case for it is not very strong. At least with the current solar activity, the observed atmospheric mass loss rates from Earth, Venus and Mars are comparable, even though only Earth has a significant magnetic field. There is a good article about these issues here [space.com]

Re:What happened to it? (5, Funny)

schneidafunk (795759) | about a year ago | (#43874059)

here [imdb.com] is your answer.

Re:What happened to it? (1)

Anonymous Coward | about a year ago | (#43874631)

here [imdb.com] is your answer.

mod parent up :)

Re:What happened to it? (1)

x_t0ken_407 (2716535) | about a year ago | (#43874321)

I recall this being due to an ancient impact that blasted away most the atmosphere, etc. I was watching some show (perhaps The Universe) that explained that there in fact lies a huge impact crater on most of the face of Mars that coincides with this theory. Just a quick Google gave me this [space.com] link -- though I got my information from the aforementioned tv show and not the link.

Re:What happened to it? (2, Informative)

Anonymous Coward | about a year ago | (#43874897)

I disagree. The prevailing theory is that solar wind tore at the atmosphere gradually due to the lack of a magnetosphere.

This itself accounts for all of the loss. In fact, it is a bit hard to explain how Mars did actually maintain an atmosphere for as long as it appears to have. Perhaps it has a weak magnetosphere in the past...

There is an impact crater that's pretty massive, but Earth has several of those too...

Re: What happened to it? (1)

Redmancometh (2676319) | about a year ago | (#43875911)

One of those "impact craters" is our core creating that megasexy magnetosphere.

Re:What happened to it? (1)

Em Adespoton (792954) | about a year ago | (#43877189)

Seems to me that those two factors combined could be the cause... impact plus solar winds. Result: no magnetosphere, not enough mass to sustain atmosphere, and solar winds slowly doing the rest.

With more mass and different geologic pre-impact conditions, it likely had enough of everything to maintain an atmosphere.

The bigger question is why our ancestors abandoned the planet and then nuked it and stole the atmosphere, but left the water.... :D

Re:What happened to it? (1)

hairyfeet (841228) | about a year ago | (#43876279)

This is why Neil deGrasse Tyson want us to do a closer study of Mars, because there is a good chance that the origin of life here can be found there. As he pointed out they had a "primordial soup" much earlier than we did, several kinds of bacteria can survive in space in a dormant state, and finally a lot of the debris from those large impacts ended up hitting us.

Re:What happened to it? (4, Funny)

basicasic (1185047) | about a year ago | (#43874429)

The original liquid was of course heavy water which (as every schoolboy knows) breaks down over time to become ordinary light water. This then floated off into space.

Re:What happened to it? (0)

SecurityTheatre (2427858) | about a year ago | (#43874905)

What? lol...

Re:What happened to it? (1)

cyfer2000 (548592) | about a year ago | (#43875787)

If there is no magnetic field protecting the atmosphere, radiation can break down the water molecules into hydrogen and oxygen. The hydrogen will then escape. As you might know water molecules have strong greenhouse effect, or they keep Mars warm. After loosing some of the water in atmosphere, Mars could not keep the temperature above freezing point, then the water left would be frozen.

Water in particular? (5, Insightful)

Anonymous Coward | about a year ago | (#43874103)

Perhaps I'm missing something, but the evidence cited in the article only seems to show that liquid of some kind once flowed on Mars. What further evidence do we have to think that it was water in particular?

Re:Water in particular? (3, Funny)

quonsar (61695) | about a year ago | (#43874225)

More likely to have been vodka according to my research.

Re:Water in particular? (0)

Anonymous Coward | about a year ago | (#43874721)

If it was close to Olympus Mons, I would suspect that it should be alcoholic.

Everybody knows that the Pastafarian Church Heaven has a Beer Volcano. Curiosity should be looking round for the stripper factory....

Re:Water in particular? (0)

Anonymous Coward | about a year ago | (#43875369)

If it was close to Olympus Mons, I would suspect that it should be alcoholic.

Everybody knows that the Pastafarian Church Heaven has a Beer Volcano. Curiosity should be looking round for the stripper factory....

Probably next door at Mons Venus [monsvenus.com]

Re:Water in particular? (1)

RS449 (2859563) | about a year ago | (#43874291)

It was Slurm...

Re:Water in particular? (4, Informative)

Antipater (2053064) | about a year ago | (#43874305)

Extremely hot or cold liquids would have done more to the pebbles than just knock their edges off - we can figure pretty well that they weren't melted or supercooled. The simplest conclusion for "liquid that flows in streams at the temperature range in question" would be either "water" or "the blood of thine enemies".

So it actually just proves (0)

Anonymous Coward | about a year ago | (#43875873)

So it actually just proves that the Red and Green men and women of Barsoom once warred here in great number as documented by John Carter.

Re:Water in particular? (2)

Anonymous Coward | about a year ago | (#43874587)

the reason for mars lack of atmosphere (or at least too thin atmosphere) is due to the end of tectonism and vulcanism in the planet.

earth loses gases all the time, but those get replenished by the gas that leaks from vulcans and tectonic plate borders.

theres a balance between gas lost to space and gas gained from lava

mars is a small planet, so its tectonism and vulcanism faded a long time ago, so it started to lose more gas than it got from lava, and the pressure dropped.

Lower atmospheric pressure means that water boils at lower temperatures, so a lot of water got evaporated, leaving the planet adesert.

Re:Water in particular? (1)

interkin3tic (1469267) | about a year ago | (#43874595)

I'd venture a guess that given the atmosphere, temperatures, and composition of Mars, liquid water flowing is the most logical culprit. Not cold enough for liquid nitrogen or helium, not enough mercury to cause it. Maybe ammonia is unlikely for some reason? And if it were beer, fine wine, whiskey, or gasoline, we'd already be halfway to Mars by now.

Re:Water in particular? (-1)

Anonymous Coward | about a year ago | (#43874719)

or liquid at all..and not high winds... tumbling the 'pebbles'.. or perhaps they were actually formed that way?
there is no evidence.. it's all speculation to make scientist community giz with glee

Re:Water in particular? (3, Insightful)

steelfood (895457) | about a year ago | (#43875719)

What other liquid did you have in mind? Water is about the simplest, most abundant, and most versatile liquid out there. Most other naturally-occurring liquids are not liquids in the Martian temperature range, or too complex for there to be a significant amount of (and this applies to the entire universe in general as well, though there may be localized anomolies).

Unless you're positing that it was something organic like oil, or artificial like formaldehyde, there's no other likely candidate liquid that's abundant, operates at those temperatures, and with that viscosity. Don't forget that CO2, the only other abundant substance on Mars, subliminates under 5 atm, and we know the Martian atmospheric pressure is lighter than ours.

Re:Water in particular? (0)

Anonymous Coward | about a year ago | (#43876077)

Yes, it could be organics.

The atmosphere of Titan is largely composed of nitrogen; minor components lead to the formation of methane and ethane clouds and nitrogen-rich organic smog. The climate—including wind and rain—creates surface features similar to those of Earth, such as dunes, rivers, lakes and seas (probably of liquid methane and ethane), and deltas, and is dominated by seasonal weather patterns as on Earth.

https://en.wikipedia.org/wiki/Titan_%28moon%29

Re:Water in particular? (1)

yusing (216625) | about a year ago | (#43877469)

We don't have further evidence at present. There are multiple ways in which pebbles might be rounded.

Much of what people think has been done by water on Mars surface could be done over eons by sand and fines suspended in winds. The winds may have been much stronger in the past. Over eons, the spacial orientation of rocks can change, again for many reasons, which gives prevailing winds access to multiple faces.

In the long term, rounded pebbles along with several other phenomena *all in the same location* may raise the probability that liquid H2O was involved too high to reasonably dispute. We're not at that point yet.

Re:Water in particular? (0)

Anonymous Coward | about a year ago | (#43878713)

Liquid CO2 isn't plausible (needs too much pressure to achieve), and other potential liquids aren't really candidates because they aren't known in any form on Mars, whereas water is plentiful in the ground as ice (detected by a variety of methods, plus the visible ice caps). It's a fair question to ask, but water is the most likely answer by far, especially when a host of other structures have been observed that are consistent with water being abundant at about the time these rocks were deposited (e.g., the drilling that MSL has been doing into bedrock further along its traverse, which revealed a significant amount of clays and hydrated calcium sulphate (probably gypsum)). They've also seen cross bedding [wikipedia.org] at other sites that is consistent with deposition under water. Although crossbeds also form in aeolian conditions (wind-blown), the aeolian ones are geometrically distinct from subaequeous crossbeds, and the ones they've seen seem to be the latter type.

Just to play devil's advocate (0)

Anonymous Coward | about a year ago | (#43874117)

I thought that the fact that Mars once contained liquid water was something that scientists have "known" for decades. What is the threshold for "definitive proof" or "final confirmation"?

Re:Just to play devil's advocate (1)

Tablizer (95088) | about a year ago | (#43874329)

It's like Benghazi: always new news that's neither news nor new :-)

Re:Just to play devil's advocate (1)

Kahlandad (1999936) | about a year ago | (#43874633)

There is no "final confirmation" in science... assumptions can not made as long as evidence for or against a hypothesis can be gathered. While there certainly is a large 'pool' of data (sorry, couldn't resist) that water once flowed on Mars, we're still a ways off from knowing that with absolute certainty. That's the main difference between science and religion.

Re:Just to play devil's advocate (3, Funny)

rwise2112 (648849) | about a year ago | (#43875383)

There is no "final confirmation" in science

I can confirm. This is true.

Sorry, couldn't resist!

Re:Just to play devil's advocate (0)

Anonymous Coward | about a year ago | (#43876141)

But you just used logic. Which trumps all =)

Re:Just to play devil's advocate (0)

Anonymous Coward | about a year ago | (#43876577)

That's the main difference between science and religion.

To be fair, it's also the difference between science and mathematics.

Re: Just to play devil's advocate (0)

Anonymous Coward | about a year ago | (#43876817)

To be truly fair, both math and science are based on axioms and postulates--a fancy way of saying you've formally assumed something. Even if axioms are considered to be "obvious", in the final assessment, both are forms of assumption. In fact, if you do some reading on number theory, you'll find that your choice of axioms/postulates has a significant effect on what you can "prove". Of course, all sufficiently complex formal axiomatic systems (think rules of production) ultimately contain statements that are true within the system, but unprovable, and such a system cannot demonstrate its own consistency internally.

Thanks for this post to Russell, Whitehead, Frege, and GÃdel.

Re:Just to play devil's advocate (2)

Sperbels (1008585) | about a year ago | (#43874923)

Additionally, Voyager has just entered interstellar space.

Re:Just to play devil's advocate (0)

Anonymous Coward | about a year ago | (#43875881)

What is the threshold for "definitive proof" or "final confirmation"?

In science? There really isn't one.

Geology (5, Informative)

Anonymous Coward | about a year ago | (#43874137)

The thick crustal material and low magnetic field have led to the loss of the atmosphere and lack of currently flowing water. Low magnetic field led to large impingement by solar wind and stripping of atmosphere. Low average density of planet let atmosphere escape. The thick crust has kept the mantle deep and there is no regeneration of gases and liquids from the interior. Low atmosphere, more radiational cooling and first water goes to ice and then CO2 goes to ice and reduces the atmosphere again. The Earth could have gone the same route, had an impact not spawned the moon and thined the planet of the lighter, thicker crustal material. Lots of imparted spin from the impact and a denser planet gets deep iron core spin to generate a protective magentic field. That field both protects the atmosphere and the biologicals from getting zapped. Would be fun to send lots of water and gas bearing comets to impact and terraform Mars, but it would all still leak out. So --- we are seeing prehistoric water, frozen in time,and relected by the rounded pebbles left behind in ancient Martian canals.

Re:Geology (1)

gl4ss (559668) | about a year ago | (#43874449)

The thick crustal material and low magnetic field have led to the loss of the atmosphere and lack of currently flowing water. Low magnetic field led to large impingement by solar wind and stripping of atmosphere. Low average density of planet let atmosphere escape. The thick crust has kept the mantle deep and there is no regeneration of gases and liquids from the interior. Low atmosphere, more radiational cooling and first water goes to ice and then CO2 goes to ice and reduces the atmosphere again. The Earth could have gone the same route, had an impact not spawned the moon and thined the planet of the lighter, thicker crustal material. Lots of imparted spin from the impact and a denser planet gets deep iron core spin to generate a protective magentic field. That field both protects the atmosphere and the biologicals from getting zapped. Would be fun to send lots of water and gas bearing comets to impact and terraform Mars, but it would all still leak out. So --- we are seeing prehistoric water, frozen in time,and relected by the rounded pebbles left behind in ancient Martian canals.

well it's obvious what we need to do. build a red slave shield around mars. then the ur-quans will all be "like wtf we were here already??" and just go on their merry way while we hold two nice planets.

Re:Geology (1)

VortexCortex (1117377) | about a year ago | (#43875583)

Would be fun to send lots of water and gas bearing comets to impact and terraform Mars, but it would all still leak out.

You need to think bigger... Re-read that part about thinning the Earth's crust and spinning up a mag-shield. Now, that's terraforming.

Re:Geology (1)

DNS-and-BIND (461968) | about a year ago | (#43876075)

No, there are no canals on Mars, you anti-scientific moron. Canals are artificial, they are made by MARTIANS!@#@!# Go back to your religion and constitution-worshipping wingnuts. Canals! On Mars! Modded +5 Informative! Ugh makes me want to puke when I see this sort of garbage in public.

Re:Geology (1)

Dcnjoe60 (682885) | about a year ago | (#43878179)

The thick crustal material and low magnetic field have led to the loss of the atmosphere and lack of currently flowing water. Low magnetic field led to large impingement by solar wind and stripping of atmosphere. Low average density of planet let atmosphere escape. The thick crust has kept the mantle deep and there is no regeneration of gases and liquids from the interior. Low atmosphere, more radiational cooling and first water goes to ice and then CO2 goes to ice and reduces the atmosphere again. The Earth could have gone the same route, had an impact not spawned the moon and thined the planet of the lighter, thicker crustal material. Lots of imparted spin from the impact and a denser planet gets deep iron core spin to generate a protective magentic field. That field both protects the atmosphere and the biologicals from getting zapped. Would be fun to send lots of water and gas bearing comets to impact and terraform Mars, but it would all still leak out. So --- we are seeing prehistoric water, frozen in time,and relected by the rounded pebbles left behind in ancient Martian canals.

Wouldn't the question be, given those conditions, not be where did the water go, but how did it ever form in the first place?

How does this confirm it was water? (1, Insightful)

Lucas123 (935744) | about a year ago | (#43874153)

It could have been any liquid with similar viscosity.

Re:How does this confirm it was water? (1)

Tablizer (95088) | about a year ago | (#43874227)

It could have been any liquid with similar viscosity.

Martian blood?

Re:How does this confirm it was water? (5, Informative)

Anonymous Coward | about a year ago | (#43874367)

There are few other candidate liquids. We know Mars has water ice. We've detected liquid methane elsewhere in the solar system, but Mars is too warm to support liquid methane. Liquid CO2 is unlikely because at Mars' current temperatures, you would need more than one Earth atmosphere of pressure to form a liquid, and a thicker atmosphere will usually mean a warmer planet.

Re:How does this confirm it was water? (1)

SecurityTheatre (2427858) | about a year ago | (#43874983)

Liquid CO2 is unlikely because at Mars' current temperatures, you would need more than one Earth atmosphere of pressure

And at ANY temperature....

Just sayin...

Re:How does this confirm it was water? (2)

SecurityTheatre (2427858) | about a year ago | (#43874965)

.... such as....

Similar viscosity, which remains liquid at the approximate temperature of Mars now and in recent past, that can dissolve a number of the minerals seen in sediment... AND can exist in large quantities.

Water... and.... uhm.... dihydrogen monoxide...

Re:How does this confirm it was water? (1)

VortexCortex (1117377) | about a year ago | (#43875591)

Except, we already found water, and chemical reactions that indicate the presence of water. Now we also have evidence the water gathered and flowed.

How do they know it was water? (-1)

Anonymous Coward | about a year ago | (#43874157)

How do they know it's not some other form of liquid?

Water under the bridge (1)

Tablizer (95088) | about a year ago | (#43874197)

The image caption reads: "The team only has pictures from the rover's main cameras. Attempts will be made to get close-up, high-resolution imagery of Gale's conglomerates in the weeks ahead using the Mahli "hand lens"."

The rover is long gone from that area. I hope they got some close-ups. Unless they want to make a "U" and do some major back-tracking, I hope this is just a case of mixing an old article with new content, being the top says, "updated".

Need it have been water? (1)

gstoddart (321705) | about a year ago | (#43874203)

Does this tell us water flowed, or merely a liquid?

It says a stream bed, but could this have been liquid CO2 or something else at some point?

I'm sure the chemistry tells them a lot, and I trust the NASA guys to know much more than I do, just curious if this specifically confirms 'water'.

Re:Need it have been water? (2)

gewalker (57809) | about a year ago | (#43874465)

You don't get liquid CO2 without quite a bit of pressure, a minimum of 75 psi / 517 kPa (5.1 atmospheres) at the triple point for CO2. Not near enough CO2 for those kind of pressures on Mars.

Re:Need it have been water? (1)

Kozz (7764) | about a year ago | (#43876123)

You don't get liquid CO2 without quite a bit of pressure, a minimum of 75 psi / 517 kPa (5.1 atmospheres) at the triple point for CO2. Not near enough CO2 for those kind of pressures on Mars.

I admit I'm not much for chemistry or physics. I find them interesting, but they're not my strong suit. What about methane, ethane, etc? For example, the lakes of methane on Titan? I wonder if they could produce similar results? Would conditions on Mars in the past have prohibited this as well?

Re:Need it have been water? (3, Interesting)

eggstasy (458692) | about a year ago | (#43874669)

There is no such thing as liquid CO2. Only artificially high pressures can prevent it from sublimating, and as I'm sure you realize, a planet that can't even retain its atmosphere is unlikely to have somehow maintained an atmospheric pressure 5 times that of the Earth in the past.
Water is an extremely common and simple substance that you can find all over the universe.
So according to Occam's razor... what else could it possibly have been?

Re:Need it have been water? (1)

SecurityTheatre (2427858) | about a year ago | (#43875049)

There are really no other candidates that occur in any volume in the solar system.

Sure, there are a few elements that are also liquid at comparable temperature and pressure. Kerosene and ethanol, for example. But something that would spontaneously form a long-lasting river on a planetary surface... mostly just water.

Besides, the few times the rovers have attempted to dig into the soil on Mars, they found water ice just under the surface. Pretty good indicator that the area once had substantial amounts of H2O.

Grammar: failing on Slashdot (1)

AmiMoJo (196126) | about a year ago | (#43874215)

What is wrong with "Water confirmed to have once flowed on Mars"? Knowing Slashdot it would probably have read "flown" though.

Re:Grammar: failing on Slashdot (0)

gstoddart (321705) | about a year ago | (#43874285)

Knowing Slashdot it would probably have read "flown" though.

Nope, flowed is a past tense of flow, flown is a past tense of fly.

Which is why I long ago gave up correcting non-native speakers of English, and have discovered that sometimes garbled English is actually far more expressive and accurate than 'proper' English.

Some of the best puns I've heard are grammatically incorrect, but completely on-point in context.

Re:Grammar: failing on Slashdot (0)

Anonymous Coward | about a year ago | (#43874475)

Knowing Slashdot it would probably have read "flown" though.

Nope, flowed is a past tense of flow, flown is a past tense of fly.

That was the joke, yes.

Re:Grammar: failing on Slashdot (0)

Anonymous Coward | about a year ago | (#43874565)

That was not a joke, no.

Re:Grammar: failing on Slashdot (2)

gstoddart (321705) | about a year ago | (#43874567)

That was the joke, yes.

Ah, but this is Slashdot, where the pedants get to be pedantic over the pedantry of other persons.

Re: Grammar: failing on Slashdot (0)

Anonymous Coward | about a year ago | (#43876943)

If the pedants don't, who will? Think of the childen!

Re: Grammar: failing on Slashdot (2)

gstoddart (321705) | about a year ago | (#43877033)

If the pedants don't, who will? Think of the childen!

No, that's a different word that starts with p-e-d.

Re:Grammar: failing on Slashdot (2, Informative)

Anonymous Coward | about a year ago | (#43874789)

Knowing Slashdot it would probably have read "flown" though.

Nope, flowed is a past tense of flow, flown is a past tense of fly.

Which is why I long ago gave up correcting non-native speakers of English, and have discovered that sometimes garbled English is actually far more expressive and accurate than 'proper' English.

Some of the best puns I've heard are grammatically incorrect, but completely on-point in context.

Flew is the past tense of fly, flown is the past participle.

Re:Grammar: failing on Slashdot (2)

gstoddart (321705) | about a year ago | (#43875363)

Flew is the past tense of fly, flown is the past participle.

Dude, you can't be that good of a grammar nazi and do it anonymously. ;-)

Re:Grammar: failing on Slashdot (1)

stackOVFL (1791898) | about a year ago | (#43874821)

Not sure about that. If it was read as "flown" I'd think we be reading more analogies tiring to relate something to swallow airspeed velocities.

Re:Grammar: failing on Slashdot (1)

ColdWetDog (752185) | about a year ago | (#43875967)

African or European?

Still flowing! (0)

Anonymous Coward | about a year ago | (#43874253)

Just not so WET, these days.

Sun cycles (3, Interesting)

Anonymous Coward | about a year ago | (#43874265)

And it will again. I'm convinced that the sun has hot and cold cycles. As it warms up, the water on Earth will be vaporized and the ice on Mars will melt. Then it cools and reverses that. Nature's test then is can we develop far enough quickly enough to get to the other planet before it's too late. Of course, this is just idle conjecture. :)

Re:Sun cycles (0)

Anonymous Coward | about a year ago | (#43875487)

The best technology to develop quickly would be the ability to live in a zero G environment with a solar radiation powering everything. Mining planetary and other rocky bodies in the solar system for raw materials.

The limiting factor is water, air, radiation, and soil. Once those are solved than the energy efficiency of living in space should be better than at the bottom of a gravity well. This makes the moon a nice target, even though its not the Lagrangian, its relatively low gravity. Once you are able to set up a self sustaining system. You can slowly add to it over time.

Of course this would require a shift from a consumer culture to a conservationist one. From baby boomers to planned and careful breeding.

http://xkcd.com/681/ [xkcd.com]

Re: Sun cycles (0)

Anonymous Coward | about a year ago | (#43876983)

The primary difficulty with living in zero-G has nothing to do with oxygen, water, food, or energy in general (those other things listed being forms of energy or precursors thereof) but the simple fact that humans evolved with gravity. Our bodies physically decompose without that external stimulus.

Solve that one, and the rest will look trivial. Centripetal force? Good luck building your Raman spaceship...

Re:Sun cycles (0)

Anonymous Coward | about a year ago | (#43876509)

... No. That's not how it works. The lack of liquid water isn't due to temperature so much as atmospheric conditions. Even if it was warm enough for all the ice to melt, it would just evaporate without any water cycle forming.

Re:Sun cycles (0)

Anonymous Coward | about a year ago | (#43876655)

You shouldn't believe everything you think.

Re:Sun cycles (1)

Stan92057 (737634) | about a year ago | (#43878199)

It had to be much hotter their for water to flow. Fresh water freeze's at 32 degrees. How much hotter would it have to be on earth in order for the sun to warm mars to at least 33 degrees.Saltwater fully saturated with salt -21 degrees unless of-course Mars could have been a lot closer to earth at one time. I dont see how it would workout otherwise.

Re:Sun cycles (0)

Anonymous Coward | about a year ago | (#43878733)

Long-term, sure. As solar luminosity increases in the next few hundred millions years it's expected the oceans will indeed vaporize and that will be the end of them (runaway greenhouse analogous to Venus). But solar cycles that viscious would be pretty obvious in the Earth's history if they had occurred previously. There are no such signs.

Delta between Mars and Earth pebbles (0)

Anonymous Coward | about a year ago | (#43874287)

What effect does life have on pebble erosion in a riverbed, or is it completely irrelevant? Are the pebbles on Mars devoid of those types of erosion characteristics?

In other words... (1)

postmortem (906676) | about a year ago | (#43874311)

Martian Republican party once ruled on Mars ;)

Re:In other words... (0)

Anonymous Coward | about a year ago | (#43874779)

Aye, they scoffed at the notion of global atmosphere loss whilst selling water rights to the Earthlings. Anything to jazz their quarterly statements.

In other news.... (1)

flandre (1278778) | about a year ago | (#43874725)

Grass is green and water is wet.

Really it took a rock? (1)

g0bshiTe (596213) | about a year ago | (#43875023)

I gathered there was flowing water there from this photo. http://www.astronomynotes.com/solarsys/pics/eberswalde_deltasm.jpg [astronomynotes.com]

Re:Really it took a rock? (0)

Anonymous Coward | about a year ago | (#43878321)

Sorry to be an AC, but I'm feeling anal enough to mention this:

The news value of this article isn't in the "Water once flowed on Mars" section of the headline, the news value stems from the "Confirmed" part.
We've all gathered that water flowed on Mars, but TFA is stating that it's finally been proven beyond a reasonable doubt.

Red planet (2)

Impy the Impiuos Imp (442658) | about a year ago | (#43875265)

> Confirmed: Water Once Flowed On Mars

I knew it! I knew those longboats with sails sailing across the dry sand were the product of someone's fevered imagination!

Good... Still no life... (1)

evilviper (135110) | about a year ago | (#43875643)

I'm glad to see strong evidence of water on Mars, after so much conjecture and build-up. It will make it that much more humbling when they DON'T find any evidence of life on Mars.

Are you sure? (0)

Anonymous Coward | about a year ago | (#43876765)

I really don't know (which is why I'm asking) but is there a significant enough difference between rock smoothed by water and rock smoothed by something else, like sand, to "know" that water caused this?

NASA celebrates the 100th confirmation of water on (1)

Autonomous Crowhard (205058) | about a year ago | (#43878729)

AP - Today at NASA there was a celebration. For the 100th time it has been able to confirm that there was water on Mars. Vint Norgecrack, Director of Mars Water Confirmations, said, "This time we really know it. Again. Honestly, truly, really, for real, pinky swear and all that."

NASA use this news to appeal to Congress to fund the Mars Planetary Water Finder. The MPF is a $22 billion project meant to send smaller probes to all currently existing landing sites and confirm that the confirmations of confirmations of water on Mars can in fact be confirmed.

Imperial vs Metric ... the fight continues! (1)

drcheap (1897540) | about a year ago | (#43878865)

"The stream carried the gravels at least a few miles, or kilometers, the researchers estimated..."

You'd think by now they would have chosen a damn system of measurement and stuck with it!!!







(link for those who just heard a woosh [wikipedia.org] )
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