Mars Had Surface Water for Eons

LukePieStalker writes "Far from being a one-time event, it now appears that surface water flowed on Mars for eons. Nasa has announced that, after descending down further into the Endurance crater, the Opportunity rover has found a 'razorback'. It is believed that this was formed by 'fracture fill' from the minerals in percolating water. Since this feature extends through several geologic layers, it argues for a long period of wetness near the surface. This would seem to substantially increase the chance that life once existed on the red planet."

Comments

How long is an eon?

[strictnein]

Is there an official length of time for an eon? I know it just means "An indefinitely long period of time" but when it comes to life developing the amount of time available is quite important.

... Eon is a very long period of time. Geologists refer to a Phanerozoic Eon which is about 550 million years long
The Archaeon Eon lasted over 2.1 billion years.

or is it:

An eon is the period of time it takes for a universe to come into being and then disintegrate again.

Re:How long is an eon?

[iamdrscience]

From Merriam Webster

1 : an immeasurably or indefinitely long period of time : AGE
2 a usually eon : a very large division of geologic time usually longer than an era b : a unit of geologic time equal to one billion years

So it looks like it's officially 1,000,000,000 years, but also a term for a really huge block of time.

Re:How long is an eon?

[Rei]

The problem is that the rovers are not equipped to be able to tell how old these rocks are - nor is it likely that any rovers any time soon will be able to do this sort of work. Labs that do radioisotope separation don't easily fit all of the categories ("small", "lightweight", "robust", and "self sufficient"), needed to send things to other planets. A sample return is a much more likely course before we can start dating these rocks.

Now, we can tell *relative* dates fairly easily with these rovers, but absolute dates are going to be a problem just using the rovers. There are some cases where you don't need radioisotopic dating, but I doubt they'll prove very useful here.

Re:How long is an eon?

[JustDisGuy]

It's as long as Slashdotters will argue over how long an actual eon is, when the reporter that used the term just thought it sounded good...

Re:How long is an eon?

[Rei]

That would involve multiple lines of dendrochronology which conform with each other and with the conventional historical account to all be incorrect, but not only that, but all be incorrect by the same amount compared to different artifacts. Hardly a realistic proposition. It also would require a truly massive calibration factor. Lastly, it's only applicable to radiocarbon dating, which is hardly the only dating method used.

The only time when the calibration factors become large are concerning objects from the 1950s onwards; nuclear testing really screwed up atmospheric carbon ratios, and introduced a geographical component. However, it gave a new benefit: we can now better track rates of carbon movement on a global scale. Also, there are the cases when carbon dating is not supposed to be used (which Creationists often use, of course); for example, ocean-dwelling organisms (which ingest recycled conveyor carbon) and organisms that spent their lives within a few hundred feet of a volcanic vent (which get deep earth carbon in addition to atmospheric carbon). This is known as the "resevoir effect".

Re:How long is an eon?

[sdo1]

How long is an eon?

Ask Universe Man. He's got a watch with minute hand, millenium hand, and an eon hand.

-S

Re:How long is an eon?

[Ayaress]

It's also worth noting that radiocarbon dating would be useless on Mars for two reasons: 1. It only works for formerly living material (all Terrestrial keeps the objective isotope of carbon around in a very specific ratio), and we have no confirmed fossils from Mars, and it would be a very long shot to count on finding them on a future mission. They'd be farther ahead just dating the rocks through other methods. 2. It's a relatively short-term dating (Creationists abuse this fact too, by pointing out that carbon dating on dinosaurs puts them right up to our geologic yesterday. The fact is, dinosaurs have been dead so long that all the carbon 14 in their remais is long since decayed beyond detectability). I forget the exact range, but as I remember, even going back as far as the KT boundry, it's already useless. If there was/is life on Mars, odds are most if not all of it has been dead for a very long time, and would again fall into the realm of more long-term dating methods. It would be more likely to produce good data if the probe relied on a dating method that could give results over a good chunk of the age of the solar system. On the off chance that we find something new enough to be interesting, I'd call that justification for a follow-up.

Mars

[Luigi30]

So does this mean that we might be able to find traces of water and/or life if we keep digging, or that the water is all gone?

Re:Mars

[Rei]

We know there's still water there; unfortunately, it's in the form of ice.

As for fossils or traces of life... who knows? All we can say is that Spirit and Opportunity aren't going to be finding it unless it's macroscopic. They can only dig centimeters deep, and don't have the sort of magnification needed to see microscopic organisms.

Re:Mars

[cephyn]

Well there's multiple scenarios. First, there's the estimated amount of water that would cause the global areological features. Take that number, and subtract the estimated amount of water locked in ice at the poles -- we can estimate this through satellites. The North Pole is mostly water ice, South is mostly dry ice.

Now, that leaves a Heckofalot of water. (A Heckofalot is an official measurement, look it up. It's just short of a Hellofalot) Anyway, that water could be underground...perhaps in shallow aquifers, perhaps quite deep. It's hard to say, we just don't have the tools yet. Then there's the portion that would have been lost. Martian gravity is lower than Earth's, so it couldn't hold as thick an atmosphere as we do. So some water might have just evaporated off the entire planet. Also the Martian magnetic field is quite weak -- perhaps it was stronger before (there is some evidence for that) but when it weakened, it would have allowed solar wind and radiation to rip away the atmosphere and carry water vapor with it.

In short (ha) If we keep digging, we may find none, a little, some or a lot of water.

Re:Mars

[Rei]

They already did that on Viking. The results were inconclusive, but suggestive of abiotic processes. The tests were as follows:

GEX (Gas EXchange experiment): Looked at gas level changes in martian soil vs. a control which it sterilized first.

LR (Labeled Release experiment): Looked for uptake of a radioactive liquid by gas presence, again vs. a control which it sterilized first

PR (Pyrolytic Release experiment): Like the LR, but in reverse; cooked the samples afterwards to see if they uptook radioactively tagged CO2.

GCMR (Gas Chromatograph - Mass spectRometer experiment): Heated soil samples and did a spectral analysis of them.

First, GCMR's results: Found an unexpected amount of ice, but found surprisingly *little* organics, leading scientists to conclude that some process was *destroying* organics on Mars.

For the others, the following would have been expected from each if there was life:

GEX, sample: O2 or CO2 released
GEX, control: No release
LR, sample: Labelled gas emitted
LR, control: No release
PR, sample: Carbon detected
PR, control: None

If there was no life, both samples and controls were expected to be the same. The real results?

GEX, sample: O2 released
GEX, control: O2 released
LR, sample: Labelled gas emitted
LR, control: No release
PR, sample: Carbon detected
PR, control: Carbon detected

In short, it was confusing, but was believed to be related to abiotic processes.

Water common?

[lecithin]

If we can confirm that there is/was water on Mars, what does this say about the rest of the Universe? Is water all that common? If we then associate water with the chance of life, out of the billions of stars, we just ain't alone. Insert Overlord comments below.

Re:Water common?

[LeahofRivendell]

Is water all that common?

Not only is water uncommon, the liquid phase is uncommon. Also, the reason it's so important is because it is less dense in the solid phase than the liquid phase, which allows it to freeze on top instead of on bottom, which in turn allows organisms to sustain life even when the body of water begins to freeze.

Re:Water common?

[AKAImBatman]

Water should be pretty common near stars as Hydrogen is the fuel which runs them. When combined with oxygen pulled near the star by gravitation, you find yourself with water. The difficulty is in finding it in liquid form. Planets and planetoids near a star will have their water blown or boiled away. This water will then travel toward the outer system. If no large body exists in the star's "temperate zone", then the water will continue on. If it hits a body outside of the "temperate zone", it will remain as ice.

At least, that's how I understand it.

Re:Water common?

[Ra5pu7in]

I had that same sort of thought. Confirmation that flowing water existed on Mars, even if none remains today, coupled with the number of asteroids / comets that have ice does tend to imply water is reasonably common in our universe. Two planets within a certain size range and within a certain distance of their star both having had water seems a better argument for the existence of water on other planets around other stars. (No Overlord comment - it would just confuse the puny humans I am controlling.)

Re:Water common?

[pclminion]

Is water all that common?

Probably yes. Hydrogen and oxygen are among the most abundant elements in the universe.

The unusual thing about Earth is that the environment is at the triple point of water. Water is able to exist as a gas, liquid, and solid all together in the same environment. This is only possible in a narrow range of temperatures and pressures. So water is probably very common. Liquid water, OTOH, is not.

As for why water is important for life, see one of my older comments.

Re:Water common?

[Artifakt]

To expand on Leah's comment - There are other liquids that are very simple atomically so they exist a lot around the universe. Two of these are Methane and Ammonia, both liquid under some circumstances. Because they are not polar molecules, the range they stay liquid is much narrower than for H2O. Their ice form is denser than the liquid, so lakes or oaceans of them will freeze from the bottom up, and there won't be an insulating layer to keep them from freezing over completely. So not only life as we know it, but some of the alternatives that we guess just might be possible are affected. Ammonia based life would only be possible in environments with a colder AND much narrower temperature range than Earth's. Freezing winters would be a critical problem instead of something life might be able to adapt around.

Re:Water common?

[Rei]

"Not only is water uncommon, the liquid phase is uncommon"

That should have read:

"Water is not uncommon; only the liquid phase is."

Our solar system is jam packed full of ice. Heck, Uranus and Neptune are best described as "Ice Giants" instead of "Gas Giants", due to their expected ice cores. Ice dominates the moons in the saturnian system, the kupier belt and oort clouds are composed mostly of ice, etc, etc. In fact, it is even theorized that Earth got its water from comets.

Re:Water common?

[Rei]

Erm, minor correction: Uranus and Neptune have ice mantles, not cores. Their cores are expected to be rock. Their atmospheres are relatively thin compared to the true "Gas Giants".

Re:Water common?

[Rei]

This requires a couple of assumptions:

1. Life can't exist in high-pressure environments.

Higher pressure environments have much wider ranges for the liquid phase of ammonia and methane.

2. Life cannot develop on planets with freeze/thaw cycles.

I see no reason why this should be the case. In fact, with methane and ammonia, you don't have to worry about cells being ruptured by freezing, so long as they don't have stiff cell walls.

Further, a "cell" is not the first life; you first have molecules that tend to catalyze the production of "similar", if not exact, molecules. The processess regionally take off. Groups of molecules that more accurately catalyze the production of their member molecules form "hypercycles" - regions which, while not distinct from each other, catalyze their own development. As these hypercycles begin to become distinct and compete with each other, they end up being walled off into "Ur-cells/Protocells" (depending on your terminology).

At least, that's one theory I've seen presented, which seems reasonable.

3. It is not hotter near the bottom.

There is no particular reason to expect this. In fact, in many environments in the universe where we expect there to be liquid, this is exactly what we expect; geothermal heating, tidal heating, precipitative convection heating, etc.

4. There are no dissolved molecules that can act as "antifreeze"

Pure solutions of methane or ammonia are unlikely.

5. Life requires a liquid solvent to develop.

While this is probably true, we don't know this for sure yet.

Re:Water common?

[markmier]

Ummmm... ammonia is quite polar. NH3 dipole moment is 1.5 D. Water is 1.8 D. (methane is indeed nonpolar).

At 1 atm pressure, ammonia melts at -108F, and boils at -28F (from GPSA handbook). So it has an 80F range of liquidity, whereas water has 212F. However, like you said, ammonia solid is more dense than the liquid. Water is one of only a very few materials (gallium is another, I can't remember any others but I bet there are some) that are more dense as a liquid.

By comparison, methane melts at -296F and boils at -259F.

Just your friendly neighborhood chemical engineer! :)

Re:Water common?

[Pharmboy]

Why water? Many Sci Fi authors have predicted life cycles based on other substances, in various and other temperature gradients.

I think the main point here is that we know that life can grow where there is water, and we have some pretty good ideas what to look for. For instance, we are looking for proof of water on Mars, and then we know to look where the water USED to be in order to find where life MAY have been.

When it comes to life that isn't carbon based and/or came from water, we simply don't know what to look for. We could be looking right at it and not see it because we have no point of reference, no experience, no tell tale signs that say "life was/is here". That doesn't mean life doesn't exist without water (or without being carbon based). It just means we would be unlikely to understand what we found with the limited tools on a probe unless the think came up and started waving "hi" to us.

Considering that water is relatively common in the areas of the solar system that we would THINK there could be life (venus thru mars + moons of outer planets), the smartest investment we can make is to look for the kind of life we know can exist, where we think it can exist. This means where liquid water is or was.

Re:Water common?

[Xilman]

NH3 Polar, well, yes, as you point out, but if you don't mind me qualifying it a bit, I'd say NH3 isn't usefully polar, in that it doesn't have the equivalent of Van der Walls forces between liquid molecules at a strength sufficient to much help stretch the range of liquidity (a tiny bit, but not much).

By a hell of a lot, actually. Compare its liquid range with methane, which has essentially the same molecular weight (CH4 = 16, NH3=17, H2O=18).

NH3 is also usefully polar in that it allows a good many salts, acids and bases to disolve in it, again like H2O. Methane doesn't.

The 2 Hydrogens in a water molecule don't line up on the opposite sides with the oxygen atom in the middle, but form a rather pronounced bend.

Correct.

By contrast the three hydrogens in Ammonia don't leave the Nitrogen sticking out by itself. They may not maintain perfect 120 degree angles in a flat plane around the N's "equator" under all conditions, but they are pretty close to it.

Incorrect. The NH3 molecule is substantially pyramidal. The H-N-H angle is close to 107 degreesIt's the flipping between the pyramidal configurations that's the basis for the ammonia maser. (Actually, it isn't, really, but unless you want a digression into molecular quantum mechanics that explanation is good enough and will have to do.)

Now as regards life forms, what applies to a relatively pure liquid is more than usually not something we can extrapolate too much to a mixture, so I wouldn't read too much into it. Our one example of liquid oceans is not exactly pure H2O, after all, and showing that there are some reasons life is less likely in close to pure Methane or Ammonia doesn't limit a lot of other possibilities.

Good! It is extremely unlikely that an ocean would be pure ammonia, any more than our oceans are pure water. It's rather likely, I suggest, that a predominantly ammonia ocean would contain a large amount of disolved water, which would raise the liquid range and make the chemistry both different and probably more interesting from a biochemical point of view.

Paul

Why is it surprising?

[Neil Blender]

If Mars had water, why would it not have it for a long time?

Re:Why is it surprising?

[xenophrak]

I think the common dogma is that a catastrophic event happened some billion years ago where Mars lost its magnetic field. The loss caused the upper atmosphere to be evaporated from solar radiation that was then allowed to pass into the lower levels.

One might surmise that since the Earth has a molten fluid core and routinely undergoes magnetic reversal that Mars once had the same type of core, but it may have cooled and solidified, rendering the field inoperable.

Whatever it's worth, I think that the ammonia presence is far more interesting than the traces of water.

Re:Why is it surprising?

[Cecil]

A significant amount of ammonia in the atmosphere that has not been broken down by solar radiation would signify that it is being generated on the planet currently. The only two methods we know of that would produce enough ammonia to be detected are active vulcanism, specifically an active volcano somewhere, which we have never seen, or microbial life. I suspect the original poster is more excited about the latter possibility.

On 20th July too.

[Skiron]

Shame them didn't actually find water today of all days - 20:17:43 20 July 69

Chances of Life

[Dominatus]

I don't quite see the obession with finding life on Mars.

In terms of science, we know it's possible, it's not an issue of "can" it happen it's an issue of "where" did it happen again. We also know that if there was life it's doubtful it went beyond the microscopic range as not only is there no evidence of that, but life existed on this planet for eons w/o going past the microscopic range. It's arguable that the natural result of life is not always complexity and size.

It seems to me the only reason people are obessed with finding life on Mars, or anywhere else for that matter, is to fill some urge that if they do, to less scientific minded (read: religious) people will be proven wrong.

Re:Chances of Life

[QEDog]

I don't quite see the obession with finding life on Mars.Because by finding life somewhere else we can learn a lot about life on earth.

What is life? Really? You will find many people with slightly different definitions just on life on Earth.

What about other planets? What if life in mars, the DNA strand twists the other way? Or what if there is no DNA. If the DNA is the same, then, maybe life in Mars and Earth have a common origin. If not, what common things do we see? What is the minimum requirement for life? And these are just a few questions I can speculate on. I think we can lear about ourselves, and the fundamentals of life on Earth by finding life somewhere else.

And that is all without any religious (or anti-religious) agenda.

Re:Chances of Life

[lukewarmfusion]

I know scientists that believe such a discovery would discredit religious beliefs... but many religious folks I know have absolutely no problem with life on other planets (or some a source other than that described in the Creation story).

One friend of mine, a pastor at a non-denomination church, argues that the Creation story is not a literal history; science can never remove God completely, no matter the discoveries.

Really, the obsession with life on Mars (or other places) has a lot of sources. As we learn more about the Universe, human beings don't want to be alone in it. We want to try and answer questions that may not have answers here on Earth, including the origins of life and the nature of evolution. Wouldn't you like to be there to witness the natural beginning or end of life on an entire planet?

Re:Chances of Life

[namidim]

First, since when does the presence of life on other planets contradict the existence of a god? The earth isn't flat and the sun doesn't orbit us either, yet somehow world religions go on. Second, how is it so hard to see the innate value and magnitude if we were to discover life on mars? Finally, why is the discovery of life only interesting if it involves little green men. Microbial life on mars would be a watershed event in it's own right. I can't even begin to list all the medical, philisophical, biological, etc implications that would immediately result.

Re:Chances of Life

[DynaSoar]

"I don't quite see the obession with finding life on Mars."

I do. But then I'm a scientist. I want to know stuff. I want to know as much as possible, and have other people in other fields find out as much as possible, because you never know what good things that can improve the quality of life can come of it. And actually, that last part is justification so that society will continue funding my research. Mostly, I just want to know stuff. It's why I became a scientist.

Also: because that's what humans do. They explore. They want to know their environment. I could probably come up with a decent hypothesis regarding cognitive dissonance driving humans' desire to decrease the number of unknowns in their environment in order to maximize their comfort level and probability of survival. But then that's the other thing I do as a scientist. Come up with hypotheses. Fact is, for whatever reason, or maybe no reason other than evolutionarily determined hard wiring in the brain, it's what people do.

Anyone not interested is free to focus their attention elsewhere. And dollars to donuts they themselves will have something like this that drives them that other people may not understand.

I'm sure you're right, that some people would use such a discovery as proof for and/or against some religious viewpoint. Hell, they did it with rock and roll music, and pretty much anything you can think of that they can use as leverage against each other in their power games. Good for them. Everyone needs a hobby, it gives them purpose in life, and it keeps them out of my hair.

Re:Chances of Life

[Kphrak]

I've never understood the thinking that if life was found on another planet, all religious people's (they mean "Judeo-Christian and maybe Islamic", not "religious") heads would explode, and God Himself would vanish in a puff of logic. What's to stop God from creating life on another planet?

The idea that Earth was the center of the universe originated with some Greek philosophers (Aristotle and Ptolemy were among these), and the idea was actually quite controversial even then. The only reason why it became canonical (plenty of Christian scientists, including Johannes Kepler, argued against it) was that it was one of the few things left from the ruin of the ancient world by the time monastic scribes got hold of it, and the ancients were so impressive that it was hard to imagine anyone one-upping them at the time. Such a theory is never mentioned explicitly in the Bible, and it's pretty doubtful that any religious person would care about its collapse. Unless there are still Christians who believe that the orbit of any planet can be described by a perfect circle...

Still waiting for fossilized remains.

[LeahofRivendell]

To me, that's the only concrete proof of life on Mars. Life is complex--there's more to it than water.

Eon = Division

[Valiss]

The longest division of geologic time, containing two or more eras. For example, an era where Mars had water and an era afterwards, where there was no water.

Another possibility

[techno-vampire]

If water is dripping into a gap caused by a fault, it might not take that long for dissolved minerals to fill the hole. Considering how big stalactites and stalagmites can get in a few thousand years with just a slow drip, how long would this take with periodic flooding followed by a long dry spell?

Can't increase chances retroactively

[ColonelPanic]

This would seem to substantially increase the chance that life once existed on the red planet.

No. Life did or did not exist on Mars, but either way, its chances are over.

What these results might increase, if true, is the chance of our discovering evidence that life has existed on Mars.

Re:Can't increase chances retroactively

[fiannaFailMan]

Okay then. It "increases the chances that it is true that life once existed on Mars." Happy now?

Re:Can't increase chances retroactively

[ViolentGreen]

Is it seriously necessary to pick apart posts and respond on technicalities? I don't think there is really much doubt about how the comment was meant. The meaning came across fine.

This remindes me of those exercises that I did in grade school where I had to write specific instructions on how to make a peanut butter and jelly sandwich. The teacher would then make a mockery of the instructions by making a mess with the ingrediants.

Few people here are lawyers so few statements are going to be hole free. Most statements here and elsewhere in the world require a little common sense to interpret correctly.

Being excessively anal accomplishes nothing.

Not mass, magnetosphere

[kippy]

Both Mars and Venus are bone dry because they have little to no magnetosphere. This allows water vapor to be broken into H and O by UV radiation and since the H is light, it can acheive escape velocity much faster when hit by unhindered solar wind.

My guesses about water and life on Mars.

[MtViewGuy]

Personally, I think that once Mariner 9 showed what is very likely former riverbeds on Mars, it's obvious that in the distant past, Mars had water and very likely some form of lower-level lifeforms.

In my opinion, here's what happened on Mars:

1. In the distant past when there was flowing water on the plant, life did evolve, with the likely chance that we had fairly advanced plants lifeforms and lower level animal lifeforms.

2. Alas, when the atmosphere thinned, the surface water evaporated, essentially killing all lifeforms except for (at best) forms of bacteria and possibly algae that could survive in today's extremely severe Mars climate, living off the water trapped under the surface of the planet.

3. I think when the Mars Science Laboratory lander/rover reachers Mars in 2009, it will find that life does exist on the planet today in the form of bacteria or something related to it.

Mars may tilt sideways for more extreme climate

[peter303]

Earth has a large moon which stabilizes the tilt angle of its rotation axis. The Earth bulges at at equator from its rotation and the pull of the moon. The moon pulling on this bulge keeps the earth's axis steepening much more than it is now- a 23-degree tilt. The tilt angle creates the seasons. If it tilted more, there'd be warmer summers and colder winters.

Mars lacks a significant moon. Therefore people speculate that it could tilt all the way over on its side sometimes and have extreme seasons. Maybe even extreme enough to melt the carbon and water ices at the poles and permafrost.

Dynosaur skeletons and oil

[HermanZA]

That is all they need to find, to cause a new space race.

Existance of Life

[Harpua22]

"This would seem to substantially increase the chance that life once existed on the red planet" I think a more accurate statement would be that this increases the chances that we might find evidence of carbon based life forms having existed at some point on mars. It is theoretically possible for life to exist without water by using another liquid solvent as a substitute. One often proposed substitute is ammonia (see article http://www.daviddarling.info/encyclopedia/A/ammoni alife.html/ ). People seem to think narrowly about the possibilities of life, and often constrain their thought process to life that is, at a very basic level, similar to life on earth. Granted, since carbon is fairly prevalent throughout the universe there is certainly a good chance of it forming life in areas other than earth, but we should keep in mind that it is not (at least theoretically) the only option.

Slashdot Categories and Mars...

[rulethirty]

Aren't there enough articles about Mars to warrant its own category within Slashdot?

Life IN Mars

[Randym]

This would seem to substantially increase the chance that life once existed on the red planet.

Every planet probably has microscopic, non-oxygen-using life INSIDE it. (In fact, it may even be NON-microscopic.) Just because we don't find it lying about the surface does not mean that it did not exist.

When we talk about 'life on earth' it's assumed that we are talking about life on the *surface* of Earth. But that surface is *7 miles thick* [depth of ocean] and the radius of Earth is *4000* miles. And we know non-oxygen-using extremophiles and Archaea exist *here*. Why not there?