Major JPL Mars Announcement Tomorrow

[dshan]

I see a major announcement is due from JPL tomorrow re Opportunity. Rumour is they're going to announce evidence for water on the surface of Mars either in the past or perhaps even the present as a result of the hematite and examination of the rock outcrop Opportunity has been poking around since roll-off.

What do you think they're going to say?

Water aeons ago?

Water recently?

Both?

No evidence of water?

Life has been discovered

Mars is more boring than expected?

[antoniseb]

From your menu, I'd go with water Aeons ago.
Maybe they'll say that the 'blueberries' are some hydrate type of rock.

[Faulkner]

I reckon they've found Martians.

[VanderL]

They will probably have found evidence of (past) water, but the water has disappeared, and they are struggling to understand where the water went and what the process was that "evaporated" all the water.
Cheers.

Oh, and they finally found the golfclub.

[VanderL]

No, wait! The layered "bedrock" that Opportunity found turns out to be a fossil bed.
There was life on Mars!

Cheers.

[Dave Mitsky]

I wonder if your flippancy is warranted, VanderL.

http://www.space.com/scienceastronomy/oppo...asa_040301.html

Dave Mitsky

[kumabear]

One would think that if it were "just" water, they would announce at von Karman auditorium. The decision to make the announcement at Webb auditorium at headquarters seems a little odd.
After all, the defining goal of the mission, according to NASA, is to answer the question "Was there life on Mars?" Following the water is just a method to attempt to answer that question.

[VanderL]

Well, no life yet, but definitely water. And the question remains, when was there water and where did it go.

Cheers.

[Spacemad]

Originally posted by dshan@Mar 2 2004, 12:19 AM
Mars is more boring than expected?

:P From your "menu" of options I would expect your last "offer" to be the most likely! :P

[Tom2Mars]

Well, I'm new here and it looks like hardly anyone is going with both, so I'll bet against the house on the off chance I might win big. I'll say both. That's why the soil is so sticky. Some kind of ...frozen silicate clay sticky thingee reaction...is holding the particles together. And, most of the water is probably tied up in permafrost or leaked into bedrock cracks left behind from impacts.

Yeah, I'm going with water, past and present.

Unless they announce that we are descended from Archaea from Mars, and then that's the answer I'm going with.

[Faulkner]

How boring, we all knew Mars once had oceans!? :P

To quote VanderL: "the question remains, when was there water and where did it go." How recently (?) was Mars a watery world like Earth?

Dave Mitsky's link earlier shows this picture, with a "fossil"-like object:



Could water cause that "spiral-pasta" shape??

[alfchemist]

I just wonder, the very low atmospheric pressure on mars would permit water to stay in one place and form a body of water. If there really was water, maybe the atmospheric pressure at the time when there was water was much higher or not necessarily? water boils and evaporates because the vapor pressure equals that of the atmosphere. If atmospheric pressure is reduced dramatically, water doesn't have to be boiled to evaporate

[damienpaul]

alfchemist is spot on, and has been mentioned in posts all over the place. Remove the air pressure you remove the water.

But yes, could it be considered 'proof' that Mars had a thicker atmosphere?

[VanderL]

Not just a thicker atmosphere, but Mars must also have had time to accumulate water masses. And I don't mean a few million years, but much longer. So it seems fair to assume that Mars' history resembled Earth's to a certain point. When did they diverge, was it recent and catastrophic (or not so recent but still catastrophic) or was it slow and inevitable. How can we interpret all the accumulated data into a real history, or will we never be able to piece it together.
All this water must have been forming rivers and lakes and oceans. But we have seen that rivers can hardly be found (just the result of a trickle of molten ice here and there), lakes and oceans (if lower areas can be called that) do not resemble anything we know. Of course without any tides, oceans would be quite different anyhow. When we look at the relief charts we can see that Mars can be divided into 2 distinctly different hemispheres; the Southern hemisphere has elevated grounds and is heavily cratered and the Northern hemisphere is not as strongly cratered and is hundreds of feet lower, like some kind of gigantic basin. Could these features have anything to do with what happened to all the water?

Cheers.

[alfchemist]

guess we have to sort out details before we could see the big picture that was. If what was being said in press releases are true that there's brine and water freezes as it's squeezed out of the mixture then these water slowly evaporates like in freeze-drying where water is frozen and at reduced pressure, water sublimes. We can therefore see that there's a process going on as far as water is concerned and maybe, just maybe, this has been happening for a very loooooooooooong time! :-) assuming of course that the premise is true.

[antoniseb]

we have to sort out details before we could see the big picture that was

True! There are some things that seem worth checking out. For example, it would be useful to get a date for the creation of the Hellas Basin, and likewise the volcanoes that are on the opposite side of the planet from it.

I can imagine a scenario in which a somewhat watery Mars with a thicker atmosphere gets heated up, dehydrated, and lighter elements of the atmosphere get boiled away by a very large impact event [Hellas], which also produces large magma pockets and crust-splitting on the opposite side of the planet where the seismic waves collide, resulting in the rift we see as well as the strangely isolated and huge volcanoes.

If the Hellas Basin and Volcanoes were created about the same time as each other, this would be evidence supporting this idea. If they aren't contemporary with each other some other big picture is required.

[alfchemist]

ups! one might say that it's brine or superbrine so water doesn't freeze at all.Well, there's always equilibrium between the gas and liquid phase. With the low atmospheric pressure, evaporation will be favored, ie, towards the gas phase. But if this has been happening for a long time, I seriously doubt that there would still be water left!

[alfchemist]

hey, antoniseb! good afternoon! :-)
I think we're getting somewhere! There must be some cataclismic event that happened which resulted in the loss of martian atmosphere that permitted bodies of water to form. This event also must have resulted in the features that we see on Mars today. Good point, antoniseb!

[antoniseb]

Good point

Thanks. I thought that all the talk was pointing toward Hellas-Creation-Event being the cataclism, but that the planetologists were simply not saying it openly because they didn't have hard proof.

Looking ahead to the future proposed missions, I don't think we'll have hard proof on this until 2012 at the earliest. I also suspect that getting data on the date of the cataclism seems lower priority than simply figuring out what water and hydrocarbons are still present.

[alfchemist]

sure is low priority! Primary purpose of this exploration is to establish if there was/is life on Mars but the underlying agenda is how to exploit the planet for practical,immediate purposes. Science will take a back seat after they have established that Mars could be habitable. But don't let this stopped you on carrying the torch, to satisfy curiousity, and to gain knowledge beneficial for the future of our planet. Carry on Antoniseb! You are not alone! :-)

[antoniseb]

One more bit of the Hellas-Creation event. This could also be the formation date for Deimos and Phobos. I imagine that an event creating a crater that size would kick enough material up that Mars would have had some thin rings for a while that should have collapsed into these little moons.

I expect a probe getting good dates for these moons would be less expensive than the cost of dating the volcanoes and Hellas basin.

[VanderL]

I expect a probe getting good dates for these moons would be less expensive than the cost of dating the volcanoes and Hellas basin.

How exactly would you date a moon (no, not asking her out)? The date you would like to find is the moment of disruption, where can you find that information?

Cheers.

[antoniseb]

Originally posted by VanderL@Mar 6 2004, 01:15 PM
How exactly would you date a moon (no, not asking her out)? The date you would like to find is the moment of disruption, where can you find that information?

The usual way is to look at the ratio of long lived radioactive isotopes and their daughter products in crystals. This assumes that the crystals were formed as the materials froze out after the blast.

[VanderL]

Would the ratio of radio-isotopes in those crystals differ from the ones outside those crystals? Why would they be different, the material is the same, or does the heating (breaking) also change the composition?

Cheers.

[antoniseb]

Originally posted by VanderL@Mar 6 2004, 03:27 PM
Would the ratio of radio-isotopes in those crystals differ from the ones outside those crystals?

When the crystals form, certain molecules crystalize. Lets say it's some Potasium sulfate or something. A certain amount of the Potassium will be K-40 [about a hundredth of a percent] at the time of crystalization, but will decay into Argon with a half-life of a billion years or so..

You can count on the crystal originally having no Argon, and the ratio of the Potasium-40 to Argon in the crystal will tell you how much Potassium 40 was there originally, and you can see how much is there now. This tells you with reasonable precision how long ago the rock crystalized. The Argon should remain trapped in the crystal as long as it doesn't get re-heated.

If there are no crystals, you can still get a sense of the age from dirt, but it won't be nearly as precise or confident.

This can be done with several well-known isotopes of various elements, so as to give a unified view.

[VanderL]

Thanks Antoniseb, that sort of measurement seems relatively straightforward, are there any plans to perform these tests on Mars or it's moons?

Cheers.

[antoniseb]

Originally posted by VanderL@Mar 7 2004, 12:07 AM
are there any plans to perform these tests on Mars or it's moons?

I've read that the consensus right now is that it would be easier to collect samples and send them home for analysis than to include the kind of instrumentation required for this work to Mars.

I am hopeful that the test equipment can be miniturized enough to send it up there in a decade or so.

[VanderL]

Are there any other ways to verify this theory? And if so are Spirit or Opportunity or the orbiting camera's eqipped to find the clues?

Cheers.

[antoniseb]

Originally posted by VanderL@Mar 7 2004, 08:15 PM
Are there any other ways to verify this theory? And if so are Spirit or Opportunity or the orbiting camera's eqipped to find the clues?

Short answer: I don't think so

It's hard to say there are no other ways except this:
It is clear that the volcanoes became inactive after the end of the last major bombardment period, as they are fairly crater free. If the Hellas Basin is not similarly free of cratering, this theory is right out the window.

The current pair of rovers aren't close enough to either the volcanoes or the basin to tell us much about that, however, if the cataclism caused the evaporation of the surface water, then what Opportunity is looking at now [magnesium sulfate crystals and other salts] could also be dated to roughly the same period.

The catch is that there is no equipment on either rover that can do isotope ratios of anything except maybe iron [the mossbauer tool has a shot there], but Iron doesn't have any isotopes with the billion-year half-lives for this kind of work, and even if it did, odds are the instrument wouldn't be sensative enough to pick up the minute quantities or the daughter products.

[VanderL]

If the Hellas Basin is not similarly free of cratering, this theory is right out the window.

The surface of Mars is indeed unevenly cratered but I'm not sure about the Hellas Basin. That can be answered with pictures from orbit, and should be available somewhere (anyone know where to find it?).
Using cratering as a dating tool could of course be more complex when periods of bombardments were subsequently wiped "clean" by other processes.
I'm having trouble imagining how a water drenched Mars can turn into this barren desert world with most of the features looking "fresh" and hardly eroded. Somehow it seems the cratering must have happened after Mars lost all of it's surface water.
Cheers.