Flowing Water On Mars' Surface May Just Be Rolling Sand Instead (theverge.com) 81
Two years ago, NASA made a big splash when it announced the discovery of flowing water on the surface of Mars. Unfortunately, according to new research from the U.S. Geological Survey, the surface features that NASA thought were made up of liquid water may actually be flowing grains of sand instead. The Verge reports: The features in question are dark streaks that show up periodically on Martian hills, known as recurring slope lineae, or RSLs. When one of NASA's spacecraft, the Mars Reconnaissance Orbiter, studied these lines more closely, it found that the RSLs were made up of hydrated salts -- meaning they were mixed with water molecules. At the time, NASA thought that was significant evidence that flowing liquid water caused these bizarre streaks. But researchers at the USGS say these features look identical to certain types of slopes found on sand dunes here on Earth. Those slopes are caused by dry grains of sand flowing downhill, without the help of any water. It's possible the same thing is happening on Mars, too. Since liquid water is key for life here on Earth, many thought these strange lines of flowing water may help support life on the Martian surface. But now these RSLs may not be the best place to look for life anymore.
Sand? (Score:3)
Well that does it, I'm out.
Re:That's science (Score:5, Funny)
We've been going Antarctica for over a century now, and we have yet to set up a remotely self-sufficient Colony there. And it has things that Mars lacks, like Water, an Atmosphere, a warmer Climate, and Polar Bears... well... Penguins actually. What does Mars have? Lots of Sand, and no Magnetic Field to divert slightly greasy Solar Atoms.
Which brings up the fact that Penguins are largely self-sufficient and happy there. They may not fly much, and their diet is limited, and on top of that, they have Penguin Breath. But we can learn a lot from them. They go for months without eating, they are warm enough, and they seem to quite enjoy Penguin Sex... even with all that Halitosis. Sociologically, Emperor Penguin Daddies babysit while the Girls have a Season Out. This is not as hedonistic as it would appear, since Emperor Penguins mate for life. They have fine Family Values.
I do wish that the Space Nutters would stop reading crappy Science Fiction and dream of nailing Podkayne on Mars. Antarctica is perfect for them. In fact, it could be a Libertarian Paradise. Antarctica has no Taxes, no Police, and not even a Currency. They could have their own Monetary System, based on the Frostbitcoin.
And it's White. Very, very White.
Re: (Score:2)
a warmer Climate
Actually not, on Mars around the equator it is up to +20C.
Re: (Score:2)
Which brings up the fact that Penguins are largely self-sufficient and happy there. They may not fly much, and their diet is limited, and on top of that, they have Penguin Breath. But we can learn a lot from them. They go for months without eating, they are warm enough, and they seem to quite enjoy Penguin Sex... even with all that Halitosis.
It's only Halitosis if they consider pukey fish breath to be 'bad'. But they're raised from infancy to believe that it is the source of all life...
Re: (Score:1)
No, not really. In terms of availability of water, this also makes little difference, because it's clear that Mars has vast quantities of water ice on the surface; whether that occasionally melts on its own or not it really not important.
But we space nutters don't really consider Mars a good target for colonization anyway: there is little economic benefit, and it's a deep gravity well.
Re: (Score:2)
The ice on the surface is mainly CO2.
AFAIK they only found water ice in a few under ground deposites.
Re: (Score:1)
I have no idea what you're trying to get at. There are vast water ice deposits on the surface of Mars covered by about 1-10m of Martian dust and sand. For the purpose of Martian colonists getting at them, means "on the surface" (as opposed to deep underground).
Re: (Score:2)
AFAIK they only found water ice in a few under ground deposites
Mars Odyssey, which is in orbit around Mars, has instruments onboard that have detected large quantities of Hydrogen in the upper few meters of most of the Martian surface. They basically work by measuring the radiation emitted after cosmic rays strike the surface, and based on that data and the pattern of these events, you can determine the element that was hit.
Anyhow, given the unstable nature of Hydrogen, and what we already know about the chemistry and mineralogy of Mars, the most likely explanation is
Re: (Score:2)
Sounds cool.
I searched a bit around, it seems they found quite a lot of possible water deposits.
Re: (Score:2)
>But we space nutters don't really consider Mars a good target for colonization anyway: there is little economic benefit, and it's a deep gravity well.
Speak for yourself. Since we have no way (yet) to adapt the human body to zero-g or radiation exposure significantly above what we get on Earth... Mars gives us gravity (but less than Earth's, which is handy so long as it's sufficient for human physiology) and a place to burrow for protection from radiation.
It gives us a place we can plausibly survive wit
Re: (Score:1)
Colonies only "thrive" if they produce a surplus, and that's unlikely for a Martian colony given current technology.
It seems to me that the most likely scenario for space colonization involves moving asteroids into lunar orbit via ITN, mining them (and making tons of money), an
Re: (Score:1)
It actually was water. Because the science is settled. Stop being a hydro-denier!
Rolling Sands... (Score:2)
... that explains why Mick Jagger looks like he does. He and his mates must have grown up on Mars!
Flowing liquid water was never that plausible (Score:5, Insightful)
Given the atmospheric pressure, and the temperature, it was highly unlikely that they had any flowing liquid water anyway.
Re:Flowing liquid water was never that plausible (Score:5, Interesting)
Liquid brines are not only plausible under Martian conditions, they have been reproduced experimentally [nih.gov].
Given the presence of large amounts of calcium perchlorate (eutectic point -74C), there are almost certainly liquid reservoirs of brine somewhere on Mars, the only question is how big they are and where/when they are exposed to the surface.
Re: (Score:2)
The whole discussion has always seemed more academic to me than anything else. Deliquescent perchlorate brine concentrates aren't somewhere you'd look for life, they're something you'd use to sterilize a surface. Even normal levels in Martian regolith are probably enough to slowly burn your skin from handling it, in a manner akin to lye. [nasa.gov]
Re: (Score:1)
That's missing the point. The calcium perchlorate deposits suggest that large bodies of water previously existed. Pointing out that life is unlikely to form in highly-concentrated caustic salt solution is odd because nobody proposed that in the first place.
Re: (Score:3)
That's not true; Mars's perchlorates are believed to be due to the same process that forms perchlorates in places like the Atacama, just on a much larger scale: UV-driven gas-phase oxidation of volatile chlorine species (such as HCl) and/or chlorine-bearing aerosols in cold, exceedingly dry environments.
The fact that Mars was once wet has nothing to do with its present perchlorate inventory.
Re:Flowing liquid water was never that plausible (Score:4, Insightful)
Re: (Score:1)
You're making the mistake of equating what's published with some measure of scientific truth. The scientific literature is a place for debate, not truth. You can't have a debate if you insist that everything everybody says is known to be t
Re: (Score:2)
You're making the mistake of equating what's published with some measure of scientific truth.
No, I clearly said "or possibly that's just the one the media stuck to". I never said anything to equate what is published with scientific truth. And I never ' insist(ed) that everything everybody says is known to be true".
You can't have a debate putting words in the mouths of others.
Re: (Score:1)
I'm not putting words in your mouth, I'm trying to explain to you where you misunderstand how science operates. Scientists are biased, in terms of what they work on, in terms of what they believe to be true, and in terms of what they publish; you don't need to look for "evidence" of that, it's part of the process. That's why the scientific literature is full of papers that provide incorrect explanations and incorrect results; the literature is pr
Re: (Score:2)
I'm not putting words in your mouth, I'm trying to explain to you where you misunderstand how science operates. Scientists are biased, in terms of what they work on, in terms of what they believe to be true, and in terms of what they publish; you don't need to look for "evidence" of that, it's part of the process. That's why the scientific literature is full of papers that provide incorrect explanations and incorrect results; the literature is probably biased towards such papers.
I don't misunderstand how science operates. I never claimed bias plays no role in science, that is your twist. I merely pointed out a specific bias. It is YOU who put words in my mouth and took that as some misunderstanding or commentary on bias in science in general.
Biases in science are not always helpful. Pointing out biases can be very helpful. Sorry I pointed a potential one out. Why do YOU misunderstand how that can be helpful?
Re: (Score:1)
And I keep telling you: your reasoning was wrong and you misidentified the bias. You said "I think its possible the scientific community was biased toward a water flow explanation" as an explanation for why a paper was published postulating water flow when new interpretations contradict that. In actual fact, the scientific community is, if anything, biased against, not towards, a water flow explanation.
That is, your reason
Re: (Score:2)
And I keep telling you: your reasoning was wrong and you misidentified the bias. You said "I think its possible the scientific community was biased toward a water flow explanation" as an explanation for why a paper was published postulating water flow when new interpretations contradict that.
Your seeming desire to tell me I don't understand science is clouded by your lack of reading comprehension. I did NOT say the bias was an explanation for why 'a' paper was published. Rather, the bias "could" explain the propensity to look at water first and focus on water based explanations.
Then, I followed with; "but this story is evidence that they are doing just that.", working hard to prove other explanations. In other words, the bias, if it exists, did not in the end prevent them from considering ot
Re: (Score:1)
Well, I think both your original statement and your level of understanding of science are pretty clear. We'll just have to live with having a low opinion of each other.
Re: (Score:1)
Actually, the presence of perchlorates is good news for the possibility of life on Mars [space.com].
Re: (Score:2)
The "safe drinking level" for perchlorate in water on Earth for a 70kg human is 32 parts per billion. The average level of perchlorates in Martian regolith is half a percent, and the hypothetical perchlorate brines were "perchlorate salts containing only the minimum amount of water to make them flow". Even bacteria do not survive in such perchlorate concentrations (only the hardiest of species can handle the half a percent found in average regolith, let alone concentrated brines). Heck, Martian regolith
Re: (Score:1)
Perchlorate is so toxic to humans because of specific protein interactions (mostly, that it blocks an iodide pump in the thyroid). Giving this example in a discussion of perchlorate effects on bacteria is downright stupid.
Terrestrial bacteria have not had any need to adapt to perchlorate brines,
Re: (Score:2)
Why, sure there is! [youtube.com] The American Petroleum Institute said so themselves in a 1956 documentary - the Martians just need to kick out their communist-ish government and they'll find it!
Re:Flowing liquid water was never that plausible (Score:4, Informative)
This Ars Technica article [arstechnica.com] was much more informative than the cited sources.
Brines evaporating should have left detectable level of salt deposits which we are not seeing.
That said, if it is sand, we should also be seeing a build-up of these darker sands at the bottom of the slopes which we are not seeing either.
Clearly we are missing something that a visit would resolve.
Re: (Score:2)
That said, if it is sand, we should also be seeing a build-up of these darker sands at the bottom of the slopes which we are not seeing either.
A possibility, though, is that the sand is weathering once exposed to the Martian atmosphere. I don't know what the chemical process would be. All it would take is a change to the composition of the material directly on the surface, and it would look different from above.
Re: (Score:2)
I didn't want to quote too much from the Ars article (which along with the comments is as usual more insightful that comments here on /.) but:
But even the authors admit there are some problems with this idea [of solid sandy traces & not water]. To begin with, when a slope destabilizes and some of the material flows downhill, the largest particles should flow the farthest. This should leave the slope in a more stable state and less likely to have RSL appear the Martian year following; instead, they seem to reappear in the same places.
Then there are color issues. Darkening could be ascribed to the uncovering of material that hasn't been lightened by its exposure to harsh Martian conditions. But many of the RSL show a complicated pattern of darker and lighter features. In addition, there's no obvious mechanism to lighten the RSL back up again in less than a single Martian year. The review suggests a coating of dust might help, but there would have to be additional factors involved.
Finally, like the salt left behind by evaporated brines, the downward flow should leave piles of material at the base of the slope and near any features like boulders that protrude from it. But there's no sign of that in most of the images. So, based on these issues, the idea that these are granular flows has nearly as many problems as the watery explanation.
So where does that leave us? The paper argues that we're right back where we started: we don't expect liquid water on the surface of Mars, and the RSL simply aren't conclusive evidence of it. "Flowing liquid water in the current Martian climate has always been an extraordinary claim," the authors write. "The observations and interpretations presented here suggest that RSL are no longer extraordinary evidence." As long as we're not sure what they are, they can't be used as evidence of anything else.
Re: (Score:3)
Re: (Score:1)
> It is a fact that Venus is the more earth-like planet inside the solar system
By mass and gravity. The surface and atmospheric conditions on Mars are closer to Earth than those of Venus, by a longshot. Mars, for instance, has remnants of a magnetic field, Venus doesn't. Mars has an average temperature of -60c, Venus is 462c. Mars has a surface pressure of 600mbar. Venus has a surface pressure of 93bar. The Martian atmosphere is mostly CO2, as is that of Venus... but Venus also has sulfuric acid. A
Re: (Score:3)
If you ask me which rock is more like Earth, for anything other than mass and density I'll choose Mars.
Other than mass, density (which is also related to the composition of the planet) and distance from sun, that is everything. Saying that Mars is more like Earth than Venus is like saying that a chimpanzee is more similar to George Clooney than an amputee, because both the chimpanzee and George Clooney have two legs and two arms. In fact, like a chimpanzee could never be a human being (like George Clooney), Mars could never be a life supporting (that is Earth-like) planet because it is too small (hence no at
Re: (Score:2)
>Off a bit on the Math there...
Some people have a human nemesis, I have decimal places.
Beating A Dead Horse (Score:2)
Re: (Score:2, Interesting)
They’ve been sending probe after lander after probe for decades now trying to prove there is or once was life on Mars. The battle between Science and Religion played out across the planets. Like the believers would ever be dissuaded by any scientific facts.
There is an international agreement on not contaminating Mars until we know that there isn't life there.
If you are sure that there isn't life on Mars then it is still of interest to prove it so that future missions there doesn't have to worry about it.
(Unfortunately saying that there isn't life on Mars is a bit like saying that there isn't a God. There is always another rock you haven't looked under so he might be there. You can only prove that something exist, not that it doesn't.)
Re: (Score:3)
Right. So rather than the Big Bang coming from basic rules of physics that "just are", it's instead supposed to come from an infinitely more complicated being that "just is"?
Why hello Occam!
Re: (Score:3)
Right. Totally the same thing. So if I was walking in the woods and three rocks just happened to be in a row, "They just happened to be that way" makes totally as much sense as "There's an invisible troll living in the woods who arranged these rocks at night."
(If you want my personal viewpoint: it's a combination of "all basic sets of rules exist in different universes" combined with the weak anthropic principle [wikipedia.org])
Infinite instances is exactly what Ockam rejected (Score:2)
So candidate theories would be:
1) The rocks are lined up because someone / something lined them up.
2) There are actually infinite number of those rocks in an infinite number of arrangements, in an infinite number of forests ...
You mentioned Occam's Razor above. Sometimes people confuse Occam's and the KISS principle. If you're really thinking about which is simpler, it seems to me that #1 is the much simpler explanation. Infinitely so, in fact. If one misunderstands Occam's Razor to mean the simpler expl
Re: (Score:3)
So we want to get into the history of Occam's razor rather than it's actual definition as used in modern English? Because Ockam never actually posited "Occam's Razor", and even the quote you cite appears to have only pertained to the subject of miracles and God's power. Rather, Ockam was frequently known to have used Occam's Razor as a debating technique, rejecting complex ideas in favour of simpler ones.
Furthermore, you need to be clear on what is meant when discussing plurality. Are you honestly sugges
I'm sure you don't want to lie to yourself (Score:2)
> So we want to get into the history of Occam's razor rather than it's actual definition as used in modern English? ... Rather, Ockam was frequently known to have used Occam's Razor as a debating technique, rejecting complex ideas in favour of simpler ones.
I'm sure you can see that is exactly what I addressed FIRST, saying "if you're really thinking about which is simpler ..." I know you can see what I wrote. I'd assume you're not purposely lying to me, and to yourself, about what I wrote, so I supp
Re: (Score:2)
Wow, surely even you have to see how dishonest your cherry picking of that paper was - grabbing from the "Positive Correlation" section, while omitting the "Negative / No Correlation" section in its entirity, and completely lying about what the summary says. It does not say that it's "moderately effective"; it says that studies have been inconsistent, few attempts to reproduce results, and that even where positive, the researchers have admitted that their results may well be psychological.
Re: (Score:2)
If curious what exactly makes this person so calm, loving, and wise, you could only do two things - ask them, then if they say they do certain things, you could try it out for yourself. In my case, I saw a group of people who obviously had *something* special going on in their lives. I asked them about it and they said some kind of power, or set of principles, which they couldn't explain, was at work when they did certain things, such as praying for guidance to do tell right things.
It's not a surprise that the placebo effect works, or that stress is the #1 killer in America. There are benefits to religion. They are simply outweighed by the drawbacks. Not just to you, but to everyone else, too. A lot of people draw comfort from being part of the Catholic church, but they're also actively funding and supporting child molestation and the protection of child rapists. And let's not forget, you know, get thee to a nunnery.
Re: (Score:3)
Doesn't mean its your God though. Or even a human God. Or even something you'd recognise as a God. In fact if we accept your proof at all then it pretty much disproves the existence of YOUR God.
Re: (Score:3)
Re: (Score:2)
You do realize the existence or non- of life elsewhere has no bearing on religion? The Catholics already have set up a protocol if any is found.
The battle I was talking about will certainly get hotter if life is discovered independent of the earth. It would certainly advance the cause of evolution and science in general with people open to new facts, at least.
this isn't news (Score:4, Interesting)
People already knew that sand/dust can cause similar features. They believed (and still believe) that this is indicative of flowing water because of seasonality, temperatures, and association with hydrated minerals. We won't know for certain until we observe flowing water more directly, of course.
And some evidence is just wind-sculpted (Score:2)
Re: (Score:3)
> I wonder why these similarities and possibilities have never been considered in the drive to prove that water existed or exists on Mars.
I'm just going to throw this out there - when you're talking about dynamic activity on another planet... the people doing this research have not only considered those things, but done their best to model them to an infinite number of decimal places.
They're looking for life, and the best way we know of to find it is to look for liquid water. So they look for possible (
Re: (Score:2)