NASA Images Suggest Water Still Flows on Mars Options

[Guest_AlexBlackwell_*]

It isn't. You can access most content older than 12 months (including Malin & Edgetts paper) for free, but you have to register as a user first. Details at:

Yes, I believe that's true, tty.

Interestingly, though, the PDF version of this particular paper wasn't available for several days last week on the Science website, though the full text HTML version was. I haven't checked since then to see if the problem was fixed.

Here is another site (scroll down to the bottom of the page) that has the PDF version of the Malin and Edgett paper, as well as a rare PDF version of the accompanying Perspectives piece by Ken Tanaka.

[nprev]

The pessimistic outlook for LOM re: this discovery would be that the same areas on Mars may not be getting anywhere near enough repeat soakings to entail a habitat. There are areas on Earth where various lifeforms lie dormant until flash rains come, but that surely requires some favorable ratio, however slight of wet-to-dry.

Re dormancy: If hypothetical Martian bugs can survive extended freeze-drying, then they should have been distributed globally by the wind long ago. Maybe we just need to land an ultra-sterile nutrient solution with an automated microscope pretty much anywhere, toss in some soil, and see what grows...

Even negative results would be most informative. If sporulated bacteria aren't all over the place waiting for water (or dilute H2SO4?) to wake up, then that would set some significant constraints on Mars' biological history--if there ever has been any.

[ElkGroveDan]

Maybe we just need to land an ultra-sterile nutrient solution with an automated microscope pretty much anywhere, toss in some soil, and see what grows...

Would those nutrients consist of nitrates or sulfates? or perhaps silicates? That was one of the things that made me scratch my head over the Viking experiment. How do we know our "nutrients" weren't a sterilizing agent? (I know, I know, you have to start somewhere.)

[nprev]

If the $$$s were there, why not have several different mixes & maybe just a distilled water-only vial as a control? Come to that, if the postulated critters were REALLY efficient, maybe the water is all they'd need; they'd eat whatever they usually do in the soil itself.

Now, light exposure is a whole other problem. Might want to do full dark, low-UV visible, and high-UV conditions (saving the high-UV for last).

[Guest_AlexBlackwell_*]

I'm not sure this has been mentioned elsewhere in UMSF, and if it has, I apologize for the repeat; however, the June 2006 issue of Elements: An International Magazine of Mineralogy, Geochemistry, and Petrology is a special issue entitled "Water on Mars."

(Download entire issue - 11.3 Mb PDF)

This post has been edited by AlexBlackwell: Dec 11 2006, 11:46 PM

[Guest_AlexBlackwell_*]

For those who are interested, David Catling of the University of Washington has an article, "Atmospheric Evolution of Mars" (2.1 Mb PDF preprint), which is in press with Encyclopedia of Paleoclimatology and Ancient Environments.

[JRehling]

Re dormancy: If hypothetical Martian bugs can survive extended freeze-drying, then they should have been distributed globally by the wind long ago.

I would have to think it would depend on the numbers. If habitability comes down to a few hectares per minute per year, I think even Good Ol' Durable Life would have a problem spreading enough bugs from one outburst site, spread planetwide, to have a prayer of any of them dropping into another eventual outburst site.

Another problem is that bacteria tend to take time to divide, whereas we haven't seen yet that anyplace would actually be wet for more than minutes. (Or at all, to be a stickler.)

This reminds me of a problem for possible bugs in the clouds of giant planets. There may always be a zone that is wet with comfortable temperatures, but any given bug would get swept down to sterilizing heat in typical situations. In the martian case, the bacteria thriving at one outburst site would have to be so numerous that a tiny fraction of them would land in friendly environments. It's sort of like the math of a nuclear chain-reaction... in reverse.

And of course, airborne dust isn't a great place to hide from UV radiation.

It seems more likely that something would sustain itself locally than to live and travel in the global dustbowl.

[JRehling]

Instead of waiting for a site to become active and then dropping a probe/lander, I was thinking of the opposite. "Seed" gully sites with penetrators or Netlander-type packages, and then cue orbital assets when something (e.g., seismic activity, water vapor, etc.) is detected.

It's amusing that both possibilities make some sense.

It will depend, of course, on the frequency and predictability of the outbursts. If there are a million possible gully locations but only 1000 of them will gush per century and we can't predict which ones will go next, then the 1/1000 stab in the dark with landers-in-waiting would not be remotely cost-effective. It's easier to imagine that cheap surveying could be done from orbit.

On the other hand, if the events turn out to be somewhat or highly predictable as to location and time then anything goes.

It has to be a priority to start to characterize the events' patterns of occurrence.

A problem would be if every gully site only gushed *n* times, exhausting a finite reservoir of ice. If so, then the places where gullies have already shown themselves could be the places where there are least likely to be new ones.

[Guest_AlexBlackwell_*]

It's amusing that both possibilities make some sense.

Actually, a combination of the two ideas might make the most sense. Assuming multiple probes/landers/penetrators could be carried, land a few at carefully selected, predetermined sites, and then hold one or two in orbit to exploit any "fresh" sites.

[Guest_AlexBlackwell_*]

Special Coverage: Liquid Water and New Craters Discovered on the Surface of Mars
Planetary Radio
December 11, 2006

[CosmicRocker]

It isn't. You can access most content older than 12 months (including Malin & Edgetts paper) for free, but you have to register as a user first. Details at:

http://www.sciencemag.org/about/access.dtl
tty

Thanks. I forgot to check that out. There were several papers being discussed, and I didn't make it clear which one I was talking about. I was trying to get the latest paper titled "Present-Day Impact Cratering Rate and Contemporary Gully Activity on Mars." Thanks to a philanthropic donor, I now have that.

The search for life on Mars is a tricky problem. We are only very recently learning what Mars is really like. It seems quite possible that any microbes launched onto the surface environment might be toasted, but life is a resilient and robust thing. Life has managed to evolve quite a number of mechanisms to deal with challenging environments on Earth. Who yet knows what it is capable of elsewhere.

Assuming it can not survive on the surface of Mars, we might need to capture it as it is expelled from a more benign, subsurface environment. Drilling down to a wet reservoir seems to be a hit-or-miss proposition unless we can accurately identify and rove to the correct locations. Yes, there are more frigid places near the outer planets where liquid water may exist, but Mars is where we need to do more exploration.

[Guest_AlexBlackwell_*]

FYI, I made a change to a post earlier in this thread.

[climber]

I was "shoked" by M.Malin's assesment of the high probability of having a crater formed in your viscinity if you stay 20 years at the same spot. So, now, I wonder of the probabilty that a meteroid hit a "gully" zone and/or hit close enough that the effect will be to activate some gullies. Has this been already addressed or the probabilities are too remote to be considered?

[Guest_AlexBlackwell_*]

It's rare that I reference another board but I recommend reading Jon Clarke's posts on this topic on the Space.com Message Boards (Space Science & Astronomy Forum), starting with this post. Some might note Jon occasionally posts here, too. "borman" also has some interesting posts in that thread.

Of course, I'd also recommend that you completely disregard some of the others

[Guest_AlexBlackwell_*]

I was "shoked" by M.Malin's assesment of the high probability of having a crater formed in your viscinity if you stay 20 years at the same spot. So, now, I wonder of the probabilty that a meteroid hit a "gully" zone and/or hit close enough that the effect will be to activate some gullies. Has this been already addressed or the probabilities are too remote to be considered?

I haven't read or heard anyone make a connection, direct or indirect, with impact events and gully activity, though some sort of seismic activity triggering the outbursts is very plausible.