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Signs of Liquid Water Found on Surface of Mars, Study Says

nytimes.com

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Re: Signs of Liquid Water Found on Surface of Mars, Study Says

#71

Post by lawpoop »

crusso wrote: post #12

R.S.L.s are treated as special regions that NASA’s current robotic explorers are barred from because the rovers were not thoroughly sterilized We're not going to sterilize our research equipment going to Mars and we're not going to search likely sites where we could find life because we don't want to contaminate them. And yet, looking for signs of life native to Mars (or even water which might support life) is the to…

I'm supposing rather that they don't want to "discover" martian microbes or organic molecules that are actually stow-away Earthlings.

Re: Signs of Liquid Water Found on Surface of Mars, Study Says

#72

Post by pfortuny »

coldtea wrote: post #21

Maybe arsenic-based life too? This special announcement for merely "signs of" (instead of corfirmation) speaks of PR and the need to secure next years budget...

This is exactly what I was thinking... There was such a hullaballo about arsenic-based life just some years ago and then it happened not to be that after all.

Mmmmhh... Since when does NASA need a press conference?

Re: Signs of Liquid Water Found on Surface of Mars, Study Says

#73

Post by Symmetry »

mapt wrote: post #44
crusso wrote: post #12

R.S.L.s are treated as special regions that NASA’s current robotic explorers are barred from because the rovers were not thoroughly sterilized We're not going to sterilize our research equipment going to Mars and we're not going to search likely sites where we could find life because we don't want to contaminate them. And yet, looking for signs of life native to Mars (or even water which might support life) is the to…

All equipment designed for landing on Mars in the modern era is extensively sterilized. The concern is that given what we've learned about microorganisms in space, this may not be enough; "Extensively sterilized" is never "Perfectly sterilized", at least, not without building it out of solid metal and annealing it in space. There was also a last-minute variance granted to the drill bit on Curiosity, which was contami…

There have certainly been metioroids starting on Mars that made it to Earth without being sterilized[1]. Now, Earth does have a deeper gravity well which might make a difference but Earth microbes have had geological epochs to make the trip to Mars wheres you'd only expect a meteoroid to remain recognizable on Earth's surface for that long in comparison.

So I figure that if contamination of Mars by Earth life was a problem it would have happened by the Paleozoic.

[1]https://en.wikipedia.org/wiki/Allan_Hills_84001

Re: Signs of Liquid Water Found on Surface of Mars, Study Says

#74

Post by Symmetry »

mapt wrote: post #62
sanoli wrote: post #50

Earlier quoted context omitted.

Isn't this nearly impossible in the long (although here I mean really, really long) term? Think of trying to minimize the chances of some flu strain in one continent from getting to the other. I mean, once humans start going here and there, what do you do, do you keep everything in containment (exhaled gases, excrements, every form of waste)?

The only way you could keep human biota 100% contained is if the humans never interacted with anything outside the welded-shut steel sphere they inhabited - in which case, why bother bringing them to Mars?

Well, shorter times delays on teleop are a useful thing. Humans can do that just as well from orbit but if you've gone all that way then the gravity on Mars might be enough of a health benefit to make it worth while landing.

Re: Signs of Liquid Water Found on Surface of Mars, Study Says

#75

Post by oso2k »

crusso wrote: post #12

R.S.L.s are treated as special regions that NASA’s current robotic explorers are barred from because the rovers were not thoroughly sterilized We're not going to sterilize our research equipment going to Mars and we're not going to search likely sites where we could find life because we don't want to contaminate them. And yet, looking for signs of life native to Mars (or even water which might support life) is the to…

I'll first refer you to my previous post about Clean Room Operations at JPL [0].

All equipment leaving Earth is sterilized. The thoroughness of sterilization varies from project to project, instrument to instrument, and the agreed to HW & Planetary Protection Plans. It helps ensure that equipment is not giving false readings. Serious money is also laid out for HW & Planetary Protection (there's a whole division of probably 150 people at JPL) and sophisticated equipment used to test for contamination.

However, if there was deviation from the original Planetary Protection Plan [1], it was likely to execute some other test, timing/scheduling conflict, or some other "administrative" reason.

And with respect to finding water on Mars, why would you send your robot to a polar cap or even a "lake" with visible/detectable water? If you're attempting to prove that water and water flow processes exist & are active on Mars, it's probably better to test a fringe area, hence, the 3.3m requirement.

[0] https://news.ycombinator.com/item?id=6809134

[1] http://www.space.com/13783-nasa-msl-curiosity-mars-rover-pla...

Re: Signs of Liquid Water Found on Surface of Mars, Study Says

#76

Post by akiselev »

dangrossman wrote: post #68
comboy wrote: post #53

Earlier quoted context omitted.

"Water is the only molecule that fits the bill, and happens to be the second most common molecule in the universe." [citation needed]

What an annoying meme. What part did you find so surprising that you want additional references, but couldn't find a better way to ask for them? As to the first part, there are uncountable examples of water-based life, and zero examples of non-water-based life. That doesn't rule out its existence, but basic chemistry makes it unlikely, and it won't look anything like life as we know it. No other liquid has the proper…

He's likely asking for a citation that shows that water is the second most common molecule in the universe, which is a quite a claim to make based on our understanding of astrophysics and astrochemistry.

The most common molecule is diatomic hydrogen and the second most common is helium. That'll likely be true for hundreds of billions of years, if not trillions, due to the way stars burn their atomic fuel. Even if you don't include atomic helium as a molecule, the second most prevalent would likely be the most reactive combination of hydrogen and nitrogen/carbon.

Re: Signs of Liquid Water Found on Surface of Mars, Study Says

#77

Post by logfromblammo »

eddd wrote: post #48
dangrossman wrote: post #41

Earlier quoted context omitted.

> I know that without water life would have never begun, but I still don't fully understand why it is necessary. "Life" is a bunch of chemical processes. A necessary prerequisite is therefore a solvent in which those chemical processes can occur, and which can move substances around, whether it's within a cell, an organism, or an environment. Of all the potential solvents, solids can't move stuff around, and in gases…

I am not good at chemistry, but liquid methane–ethane wouldn't fit the profile?

I'd order the candidates for the basis of lifelike chemistry complexes as follows: H2O, NH3, SO2, HCOOH, CH4.

A lot of the common molecules aren't good solvents or react too readily with other common elements or molecules, like oxygen or halogens. And molecules that are good solvents just aren't common enough to dissolve much of anything.

Methane would probably only work in an oxygen-deficient environment, and ethane wouldn't form enough by coincidence to be a meaningful solvent in comparison to methane or other simple organics.

And it just so happens that H2O is very common and a great solvent, so any other potential solvent would probably have a little water in it anyway. And if it's there, a lifelike chemistry complex would probably make use of it in some way.

Re: Signs of Liquid Water Found on Surface of Mars, Study Says

#78

Post by Retra »

brianstorms wrote: post #63

Dumb question probably, but here goes: Given the latest NASA news about water on Mars, as in, “flowing water on today’s Mars,” I am still trying to figure out how that would work. If water boils at 79ºF when the atmospheric pressure is lowered to 0.5psi, what would it boil at given Mars’ atmospheric pressure of 0.087psi? How could Mars, which barely has an atmosphere, support liquid water? Why would not the water bas…

You can also have temporary streams that flow while they're evaporating. It just means you won't have long-term pooling anywhere.

Re: Signs of Liquid Water Found on Surface of Mars, Study Says

#79

Post by beambot »

They won't explore the water-flowing sites to: "minimize the chances of life inadvertently crossing the solar system."

So let's just spread life intentionally. It seems like that is one of our goals anyway -- not necessarily for governments (ie. NASA), but certainly for private space flight.

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