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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

#41

Post by dangrossman »

eddd wrote: post #33

I know that without water life would have never begun, but I still don't fully understand why it is necessary. It is still big discovery though, if life is that common I think we should be more careful during migration there, "Marsian" common cold could wipe out the entire human colony.

> 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, only volatile and highly concentrated substances would have a chance to react. It's also too easy to move around in a gas: potential gas-based "life" would just...fall apart.

So the solvent and carrier being a liquid is also likely a prerequisite for life. It also has to stay a liquid at a relatively wide range of temperatures, and be abundant enough so that all the rare coincidences that might lead to life have a chance of happening and perpetuating.

Water is the only molecule that fits the bill, and happens to be the second most common molecule in the universe.

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

#42

Post by nsxwolf »

ForHackernews wrote: post #37
nsxwolf wrote: post #18

Latest incarnation of the perennial headline... Best evidence yet of water on Mars! I've been enjoying these all my life. This and "Nuclear fusion created in a laboratory for the first time" headlines. My favorite best-evidence-yet-of-water-on-Mars was that time the Phoenix robot scooped up an ice cube and took a picture of it.

This finding is about contemporary, liquid, water.

Not a new discovery in itself, either.

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

#44

Post by mapt »

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 contaminated between sterilization and launch by briefly opening the box in a lower-spec clean room.

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

As we enter an era of inexpensive launch capacity, the sterilization step is actually so expensive it may exceed the cost of the launch vehicle. There is a case to be made for dropping these protections: They're a barrier in the way of a widespread robotic exploration mission, and a manned mission is going to be implicitly contaminative, since you can't run humans through an autoclave. The most conservative route to detecting life before sending humans is years and years of robotic launches to a variety of regions, with several sample returns. It's arguable, but I'm not sure we have the stomach to do that before the 2030's, there's no sign of the major expansion of NASA funding that would be required for the decade of exponentially escalating robotic precursors to a human mission, on the horizon. Given that we're apparently not going to protect Mars from life, that brings into question why we should bother pretending that's what we're doing today. There have already been substantial transfers on previous landers and impactors.

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

#45

Post by czinck »

lmkg wrote: post #31
gambiting wrote: post #15

Earlier quoted context omitted.

The article mentions how equipment that needs to be sterilized is baked to a very high temperature - but I wonder, can it not be sterilized with radiation, like we already do with food? All electronics on a rover are already radiation hardened, after all Curiosity has to work while having a chunk of plutonium strapped to its back. Is this not an option of some reason?

Shot in the dark: Killing organisms is not sufficient. The corpse of a bacterium is still a contaminant: It still has organic compounds that can be measured by our equipment, and potentially interact with organic compounds on Mars. For our purposes, the bacterial corpses must be fully incinerated.

I remember hearing something relatively recently about how they detected some complex molecules with one of the rovers (indicative of life creating them), but the leading theory was that they were leftover from when the rover was being built and weren't cleaned enough. So that's definitely a possibility, we aren't looking at a slide and seeing them move, we're just looking for some chemicals so dead bacteria trips the sensors just as well as live.

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

#46

Post by icoder »

tempVariable wrote: post #27
a3n wrote: post #26

If there is water of any sort on Mars, ice, liquid, salty, whatever, I think finding life on Mars is inevitable. Life is very, very persistent, and niches will be filled. Unfortunately it's also all but inevitable that we'll bring some with us, if we haven't already. Life is persistent, and ever-surprising.

Interesting. I read that in Jeff Goldblum's voice as well. Were there any missions that lifted off Mars and came back to Earth ?

I think your parent post was talking about that we may have taken earth-life to Mars (not vice versa)

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

#47

Post by kenbellows »

charleywolters wrote: post #36

I mean that's great news but didn't they announce this like 10 times before? Isn't there a meme about this, that NASA announced they found water on Mars like once a year?

My understanding is that current liquid water has yet to be found, and this is the best evidence of it we've ever had. Am I on the right track?

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

#48

Post by eddd »

dangrossman wrote: post #41
eddd wrote: post #33

I know that without water life would have never begun, but I still don't fully understand why it is necessary. It is still big discovery though, if life is that common I think we should be more careful during migration there, "Marsian" common cold could wipe out the entire human colony.

> 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?

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

#49

Post by danenania »

eddd wrote: post #33

I know that without water life would have never begun, but I still don't fully understand why it is necessary. It is still big discovery though, if life is that common I think we should be more careful during migration there, "Marsian" common cold could wipe out the entire human colony.

Water is necessary for all "life as we know it". There could be configurations we don't know about that allow life to form from radically different constituents. The universe is big enough to allow for the possibility, but it's so theoretical that we have no framework for understanding how these kinds of exotic lifeforms would work or how to look for evidence of their existence.

So while we shouldn't exclude the possibility, "life as we know it" is the most sensible place to start.

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

#50

Post by sanoli »

ChicagoBoy11 wrote: post #24
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…

And that someone seems to be this lady, with this most BAMF job responsibility ever: “These are ongoing conversations,” said Catharine A. Conley, NASA’s planetary protection officer, who coordinates the efforts to minimize the chances of life inadvertently crossing the solar system.

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)?
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