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

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

[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.

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?

[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?

[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]

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?

[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

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: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.

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.

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.

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...

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?