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Water Not a Good Enough Guide To Find Alien Life
An anonymous reader noted an article in Cosmos that questions the conventional wisdom of the "follow the water" strategy of seeking extraterrestrial life, saying "There's an awful lot of places where water could exist — either on the surface of the Earth, or deep within it — yet life is largely concentrated in a small sliver of this."
To find aliens, follow the latinum!
It seems to me that "follow the water" is better than seeking randomly -- if you find no water, then there can't be any life (as we know it) anyway.
Sure, if you find water, it's not a guarantee that there *is* life -- but it seems like a good way to weed out "definitely no" prospects.
Esli epei etot cumprenan, shris soa Sfaha.
So my layman's knowledge of how we gather information on the composition of a planet involves with analyzing the spectrum of light reflected by the surface of that planet from its nearby star. While molecules in the atmosphere also reflect the light and influence it, what's below the surface is based on that assumption. From there we can use other methods to determine its size and how far it is from the star it orbits to check pressure and temperatures.
... so why is this even being brought up? The article even ends with the researchers agreeing that presence of water is still our best approximation and that there should be no change in strategy.
We cannot measure the water beneath the surface (to my knowledge) so the example of the earth's composition of water is moot. If you were to take the surface of earth covered by water and then that amount of water that contains life, I think the percentage would be much higher. The microbes and small organisms that our oceans are teaming with alone would be a scientific goldmine on another planet. Of course the deep trenches of the Atlantic and Pacific will throw off your rates but we can't measure them anyway on another planet or even water in the mantle
If water isn't good enough, what is better?
My work here is dung.
You know, the earth has bacteria and fungi floating around high in the atmosphere and deep undersea -- probably even under the deep ocean, though we haven't looked there yet.
Tiny sliver... HA!
-l
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Everywhere on Earth we find water, we find life.
He's an idiot. Nothing to see here, move along.
select * from universe where water>0 and ___
fine, add to the where, but everything we know suggests that the "water>0" ought to be in there.
You're right. I should have said "follow the quatloos".
If life is just an evolved entity composed of randomly assembled machines, as some biologists claim, then it begs the question of wether or not there might be 'life' out there that is not water based, but based on say, sand -- or silicon.
ever bother to read them? I haven't had an article accepted in over 10 years and I suspect it's because I read the link I am referring to and write an appropriate headline.
It simple states that water can exists in environments that is hostile to life as we know it.
No shit, Sherlock.
I do take issue with the idea that only 12% of the water on earth has life. AFAIK, a cup of water from any natural source in or in the ground has some sort of life in it.
The Kruger Dunning explains most post on
I always thought of "water litmus test" as a criterion of where NOT to find life (no water, no life), rather than where to FIND it.
It's just one of many requisites of life as we know it and since there has been many instances of observations of any of them, finding water seems rather exciting.
I do not believe in karma. "Funny"=-6. Do good and forbid evil. Yours, Oft-Offtopic Flamebaiting Troll.
And Everywhere on Earth we find life, we find water ... ahem
I don't caim having read every single one, but I think this is the dumbest news item in Slashdot in months.
Maybe intelligence is just concentrated in a small sliver of it!
"questions the conventional wisdom".... I think you mean: contradicts popular opinion of biologists and journal articles.
Slashdot has become the anti-science. Today's headlines are more like Digg's.
It's not clear what Lineweaver is trying to say, here. Even when I took graduate astrobiology nearly 10 years ago, we were taught that you needed three things for life: raw elements (CHON, in particular), water, and an energy source. From the article, it sounds like he thinks he's had this revelatory notion just now.
Of the three ingredients, water does seem to be the hardest to find in sufficient abundance for a good likelihood of life arising anywhere. There are certain the raw materials and often energy sources available in many places, but water seems to be the missing factor in most of the solar system. So it's not a sufficient condition, it does seem like the smart thing to look for first.
(Also, his 12% figure confuses me. Is he including the entire mantle, for example? Because there isn't a lot of water there, as I recall, so you wouldn't expect to find a lot of life there. That alone would pretty easily throw the calculation in favor of his result. However, we have found life in deep rocks under the Earth, which is still pretty amazing and suggests that it's danged hardy.)
Yeah, I think we need to re-examine that philosophy.
Everywhere we seem to look now we are finding water, even in its molecular form in deep space dust clouds.
I must say I am highly sceptical too of the methodologies employed by the people looking for it. I mean, these are the same people who used the same methods, which haven't changed much for the past 50 years declaring water is impossible to exist on the moon for example or on mercury.
It would seem the assumptions are still very simplistic and it just goes to show how deficient the science is and its methods because when better instruments become available, assumptions have to change to usually a large degree.
Normally I usually judge a fields maturity and rigour by how well the thinking processes can predict what better instruments in the future reveal and the worse fields in my opinion are physics (sub atomic) and planetary astronomy.
Physics has just had huge correction in the past 5 years, and it will probably get another large correction in the next 10 years again.
-Hack
Got Geometrodynamics? Awe, too hard to figure out? Too bad.
... or methane
If libertarians are so opposed to effective government, why don't they all move to Somalia?
But due to a shitload of oil in that water, we can't reliably say that if there's water, there's life. Lots of dead things, though.
And some oil-eating microbes. Hey look, we found life!
You see? You see? Your stupid minds! Stupid! Stupid!
Thats very possibly true (thus the appended "as we know it".) Unfortunately saying "Here are all the reasons you might be wrong" is a lot easier than determining new approaches and going out and looking, and you've got to start somewhere.
So until new evidence points us in another direction, "follow the water" is the best direction we have.
WRONG ! What I love about these so-called scientists is their assumption that life elsewhere in the
universe must be based on Earth-like metabolisms.
Yours In Akademgorodok,
Kilgore Trout
It's life Jim, but not as we know it!
the preceding post was not spell checked... suck it.
So water is a necessary, but not sufficient condition for life (as far as we know). This really isn't new knowledge. We still want to look for water. We just have to pair that with other necessary conditions to increase our odds. Of course, we probably only have a small subset of necessary conditions for life here on Earth, so we don't entirely know what to be looking for.
"Open the pod by doors, Hal" > "I'm afraid I can't do that, Dave" sudo "Open the pod bay doors, Hal" > alright
We come in peace, shoot to kill.
Quidquid latine dictum sit, altum sonatur.
"since there has NOT been many instances "
I hope people got it.
I do not believe in karma. "Funny"=-6. Do good and forbid evil. Yours, Oft-Offtopic Flamebaiting Troll.
have estimated the volume of the Earth where liquid water can exist, and calculated that life inhabits as little as 12% of it.
And what about the volume of Earth where liquid water can not exist, what percentage of that is inhabited by life?
Well I'm not a scientist. But I know all things begin and end in eternity.
I'll trade all the quatloos for Shahna... She can be my drill thrall any time.
I will never understand the "there can't be life there because most of the life from our planet couldn't survive there" argument. I think it's perfectly reasonable that life could evolve elsewhere without water. In fact, quite likely. Life will adapt to the conditions from which it emerges, not seek to replicate life on earth.
12% of the water on this planet supports life. This does not imply that only 12% of the planets that have water will have life as he claims. You'd have to assume that all other planets are completely uniform, with none of the variation in environment that our planet has, and apply a single potential water bearing environment to each planet for that to be the case. I don't think we've found a single uniform planet yet, applying that to every planet is ridiculous.
Only 12% of my car can support a working engine, if you put it in the trunk or seat, it won't work, only the engine bay. This does not imply that only 12% of cars have engines.
This sentence no verb.
Well I am not saying it is impossible. But water has a lot of really unique chemical properties that makes randomly evolving life more likely. Being that it devolves a lot of chemicals, as well as it is sticky could come in handy in making life processes, Oh lets get rid of those pieces and glue these together while their bonds are week they stick together for a while then split. While silicon my have a lot of life giving properties for it to occur naturally/randomly you would need some medium to try to create random combination. Otherwise Sand/Silicon will be quite happy in sand like state.
If something is so important that you feel the need to post it on the internet... It probably isn't that important.
This article assumes that life is exactly as it is here. Even here though, it survives near the boiling point of water, in ice, near the mantle, and even a bit in the air. Water certainly helps, and isn't too bad to follow, but any planet in an appropriate place makes at least a bit of sense to check. Even the clouds of Venus, which although they contain sulfuric acid, also contain water and carbon dioxide, are dense and have a lot of electricity, and are nearly as dense as water in places. Seems to me not too terrible a place for microbial life to develop, or maybe to be inserted by us, and watch what happens.
Where is the mod rating for "scary"? Also,
Ah, but you see, based on our sample size of ONE planet, we've determined the conditions for life on all planets.
FTFA: "After compiling observations of life in extreme environments, the researchers found that liquid water in only a limited range of temperatures and pressures can support life." What bothers me the writers don't seem to understand this supposed range is contantly changing as scientists discover new enviorments teeming with life. Also, life isn't just IN the water, it's all around it and all around us.
Comparing silicon to water is wrong - silicon based life could exist, but we are not water based life, we are carbon based. Water is a solvent which we use, so where we'd need to look is where there are other liquid solvents and enough energy to allow the required reactions to happen. As already said, liquid methane might do the trick as a water substitute, but silicon wouldn't.
You wrote:
"Do you have a means of searching for these non-earth-like metabolism life forms?"
Yes. The means is called SETI.
I hope this helps you in your search for alien life.
Sincerely,
K. T.
News flash! Finding water is necessary but not sufficient to finding life (as we know it.)
All I have to say is: duh!
Yeah, because in all of the universe, life will only exist as we know it.
That is the epic logic failure of the whole thing.
And it’s incredibly arrogant.
Another milestone on the road of
- “The white male is the only one that really can think.”
- “The earth is obviously the center of the universe.”
- “Whites are the supreme human race.”
- “Men are superior to women.”
- “Humans are the only ones with emotions.”
- “Humans are the only ones who can actually think and reason.”
- “Humans are not animals but ‘special’.”
- “All life is water-based and requires oxygen” <-- here.
Despite we having life (bacteria) on our very own planet, that does require neither.
Any sufficiently advanced intelligence is indistinguishable from stupidity.
As anaerobic sulphur-eating bacteria exist on earth, i'm surprised that the presence of sulphur isn't given as much stature as the presence of water.
Nobody is saying there can't be life without water.
They're saying that since we have no idea of what it would look like, or how to look for it, there is simply no point in trying to look for it.
Tell me, how would you undertake to look for the conditions of life that we don't even have any clue as to how it works chemically? At which point, you could look at any environment and say "well, we can't rule out life there" -- which basically serves no purpose. That doesn't narrow your search in any meaningful way.
We have no ability to posit a theory, test it, or look for it when water isn't involved. At least by sticking with water within a range similar to that of Earth, we can intelligently say "well, we have life that lives in 150C, that place could as well".
There really isn't any way we can look in places that are outside what we can understand. From a science perspective, that's just simply a dead-end at present.
Lost at C:>. Found at C.
If life is just an evolved entity composed of randomly assembled machines, as some biologists claim, then it begs the question of wether or not there might be 'life' out there that is not water based, but based on say, sand -- or silicon.
That is not what "begs the question" means.
http://begthequestion.info/
If Slashdot were chemistry it would look like this:Cadaverine
Anyone wanna take an open mind for a minute? Someone else brought up a good argument- water and building blocks for life are *everywhere*. Recent discoveries point to complex and potentially life-forming DNA-like molecules happening naturally on asteroids throughout the universe, which could easily seed life all over, and asteroid impacts seed life all the time anyway (er, maybe). So the question becomes- shouldn't we be looking wherever there's life on Earth? And there's life on Earth... pretty much everywhere. Under heavy pressure, under light pressure, in water and in methane and deep beneath the crust feeding on minerals. We actually have good reason to believe there's life out there in our own solar system, even if it's just microbes feeding on ice caps. Water is still our best indicator, sure, but it would suck incredibly much for us to miss out on a wealth of planets covered in swarms of life (even non-sentient life) just because we didn't use indicators we already know about.
---Vote None of the Above---
I remember a few years ago many were saying that slashdot jumped the shark, to the point where saying it jumped the shark had jumped the shark.
this story submission is sharks jumping sharks jumping sharks {...} sharks all the way down
Actually, liquid methane, and methane ice, are looking like possible life supporting alternatives. maybe.
wake up and hold your nose
They went from "follow the water" to "follow the water and the right temperature and pressure".
My guess is that once we are able to properly explore other planets and moons it will be rare that we find one that doesn't have life of some source. Abundant life? Perhaps not. But my guess is that mars, Jupiter and just about every other planet will have at least some life deep in the bedrock or floating around in the atmosphere where its hard to find. Moons like our own might be dead, due to the complete lack of geologic activity and atmosphere. I think what scientists are looking for now is abundant life, like what we have here on earth. And in that, I think we'll need reactive materials in liqid and gas form like the oxygen and water earth has.
> Sand/Silicon will be quite happy in sand like state.
at normal earth temperatures and pressures
It seems to me like the thing to do is to look for anomalies and patterns... and especially anomalous patterns.
But looking in places that look familiar is a pretty obvious start.
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
Looking up some of the author's actual publications on this issue shows some very interesting details that greatly modify this picture. See: http://www.mso.anu.edu.au/~charley/papers/Jones&LineweaverProceedingsv7color.pdf.
Most remarkably he calculates that 99% of the Earth's ACTUAL liquid water contains life!!
This 12% business is the volume of the Earth where liquid water can physically exist due to its pressure-temperature phase diagram - whether or not there is actually much (or any water) there.
There are yet more limitations on this claim: it is based on the presumption that there is no life below 5 km in the Earth's crust. This is a region very slightly explored, so it can hardly be said that this claim is based on extensive direct observation. The assumption is really that the temperatures below this depth are too high life to exist (the assumed limit is 150 C). But organisms known to survive this temperature dormantly (tardigrades) are actually complex organisms (not simple extremophiles), and it was only recently that organisms were discovered that actually thrive above 121 C (the temperature of an autoclave), so the assumption that this is really the upper limit seems weak.
And the claims get even weaker. Why have we only recently discovered thermophiles above 121 C? Because there are very few accessible locations where liquid water can exist above this temp in which to observe it! Concentrated salts can raise boiling points only so far, beyond which only considerable pressure will keep it liquid. Probably the only environments we can access currently to investigate the >150 C regime are the black smoker vents on the sea floor, where emerging water hits 400 C (before rapidly cooling due to mixing).
And by this same token, the high pressure high temperature liquid water regime will be impossible for astronomers to directly observe anyway (its buried under kilometers of rock, or deep, dense atmospheres, don't ya know).
So if it is an environment where we can actually hope to OBSERVE liquid water (rather than simply postulate its existence) then yes indeed, it is almost certain to be one where life-as-we-know-it can exist.
Starships were meant to fly, Hands up and touch the sky - Nicky Minaj
Well, it wasn't long ago that we were finding the first exoplanets. Now, we've found a whole lot of them.
However, damned near everything is anomalous since some of these planets are pretty extreme in terms of temperature, proximity to sun, what have you.
I think we're going to need to catalog lots more planets before we start seeing patterns that might point us to lifeforms we can't fathom yet.
Lost at C:>. Found at C.
the technology has got to be improved if were are to have any success... [IMG]http://imgur.com/1q6Fq.jpg[/IMG]
Exactly, we should probably be looking for any form of liquid solvent, not just water. Of course, a completely arid and barren planet probably wouldn't have the necessary conditions for life to begin (primordial soup and all), so let's not focus there.
Write your representatives! Repeal the 2nd Law of Thermodynamics!
It could have gaseous life.
Why do we need solvents? Because solids react slowly. Gases have no such restrictions, and arguably are even more "free" than liquids to react. Gaseous life would have no dependency on "liquid solvents".
Bingo Dictionary - Pragmatist, n. A myopic idealist.
Nobody cares
Ultimately, the fact that we are looking for a small part (water-based) of the larger search-space (all life) relies on a certain anthrocentric bias.
We want to be the only ones... because otherwise, we wouldn't be special anymore (especially important to the religious crowd)
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It's unlikely enough to assemble genetic material (DNA/RNA on Earth) in a protective sheath (lipid bilayer here) in a liquid, how much more unlikely in a gas? It also means that unlike a small pool which could collect the necessary elements to create compounds in necessary quantities, these components disperse quickly in a gas. That same effect that would make life react quickly (chemically) once present would also reduce their likelyhood of appearing at all.
It's also possible extra-terrestrial intelligence could be in the form of beings made from pure energy and living in the center of stars, but it doesn't seem like the place we should start to look for them...
Write your representatives! Repeal the 2nd Law of Thermodynamics!
I just want to reiterate what the parent said, as I'm becoming frustrated with all of the "why do we assume it can't exist if it is not like us" posts.
No one is claiming life cannot exist without water, we are only stating that life as we know it cannot. Since we have no idea what the hell we would be looking for otherwise, and since we have limited (and in the search for ET life, extremely limited) we have to determine some heuristic for our search. Since water is A) easily detected with telescopes, and B) a requirement for life as we are aware, it is so far our best means of refining our search. There may be some amazing form of X based or X requiring life out there, but since we do not know X, it is not at all helpful to acknowledge its possible existence. If, on the other hand, we happen upon X based/requiring life, we can then include X in our parameters.
Please stop assuming that this is some circa 1900AD Newtonian Physics style oversight.
http://www.princeton.edu/main/news/archive/S16/13/72E53/index.xml?section=newsreleases
I saw a claim somewhere (I think it was Stephen Jay Gould) that the majority of biomass was subterranean. I can't find a substantiating link, though.
It's unlikely enough to assemble genetic material (DNA/RNA on Earth) in a protective sheath (lipid bilayer here) in a liquid, how much more unlikely in a gas?
Why is "a protective sheath" necessary (except for your lack of imagination) ?
It also means that unlike a small pool which could collect the necessary elements to create compounds in necessary quantities, these components disperse quickly in a gas.
The better for spreading the life to a large volume of an ecosystem, so that sparseness of "nutrition" / consumable energy, is not a problem.
It's also possible extra-terrestrial intelligence could be in the form of beings made from pure energy and living in the center of stars, but it doesn't seem like the place we should start to look for them...
So? Why is this relevant?
Anyway, if it lives in the center of stars, and since humans can't go / send probes to such places yet, of course. Finding life is not important enough to spend many orders of magnitude more money than we are already spending, so no need to accelerate efforts to send humans/probes to center of stars either. But so what?
Bingo Dictionary - Pragmatist, n. A myopic idealist.
Ah, but you see, based on our sample size of ONE planet, we've determined the conditions for life on all planets.
No, but we have a very good idea of what kind of conditions life-as-we-know-it requires, so we can concentrate our limited resources to search in places where it's most likely to occur.
We have a galaxy with hundreds of billions of stars, likely trillions of planets and tens, if not hundreds of trillions of moons, not to even mention all the asteroids, comets and Kuiper belt debris. What are the tell-tale signs that you would use to narrow down the search for, say, silicon-based life? Or are you just going to check all the objects one by one in alphabetical order?
If life is just an evolved entity composed of randomly assembled machines, as some biologists claim, then it begs the question of wether or not there might be 'life' out there that is not water based, but based on say, sand -- or silicon.
Sure, you say that now, but if there were a probe that could be sent ANYWHERE in the universe in a blink of an eye, I bet you'd still send it to a planet orbiting a sun-like star at an Earth-like distance that has water on the surface and oxygen in the atmosphere, wouldn't you?
You little fascist.
Your signature contains a syntax error in most languages, but I imagine that DoWhatIWant() returns with a functioning closing parenthesis when you want one.
In looking our global ecosystem it seems to me that it is extremely fragile. There are myriad of unique characteristics of our planet that come together to support life.
Earth is just the right size to allow for a decent atmosphere.
It is just the right distance from the sun which allows for water in liquid form.
The iron core creates a magnetic field that protects us from solar radiation.
Also consider that we have just recently been able to find exoplanets, and most of what we have found are large jupiter-like planets. It is no wonder that we have not found another life-supporting planet. (yet)
One thing I would like to note is that all the great concentrations of life on this planet occur in places that are chaotic. Places where there is a fabulous mix of nutrients.
Look at the undersea steam vents, coral reefs, rain forests, and marshes. All of these are places where there is a lot of 'mixing' going on. Natures' blender, if you wish. And on a global scale, the earth itself is a great mixer. Water washes down the mountains and evaporates into the air. The moon drives tides. Currents of water and air circulate around the planet. Volcanoes and plate rifts leak minerals into the oceans and air. Fresh and saltwater mix.
Now consider the deserts of our planet. Lots of sun, but no water. And the underwater 'dead zones' devoid of sunlight, oxygen, or nutrients. These are all places where there is very little moving and mixing.
Yet some places we would never think that life could exist, it does. And it does so because of the mixing. Water is a great facilitator to that mixing, but perhaps not a requirement.
Life flourishes in chaotic environments. It is stagnation that is the bane of life. If we want to find life in the variety that matches earth, we need to find planets that are varied and wild like ours.
oldhack: "Security is a waste of money until shit hits the fan. 5 minutes later, it becomes waste of money again. "
Why is "a protective sheath" necessary (except for your lack of imagination) ?
There are a few reasons. First you need to understand why it is there - to control what can an cannot get in or out of the cell (for lack of a better word - without the membrane it wouldn't be a cell). If there is no membrane, all you have is chemicals which happen to be close together - there is nothing to hold them together so there is no reliable way to control reactions, so there is no life. Life is essentially just a set of self-controlling reactions which can self replicate.
The better for spreading the life to a large volume of an ecosystem, so that sparseness of "nutrition" / consumable energy, is not a problem.
That only works if the life can form in the first place.
It's also possible extra-terrestrial intelligence could be in the form of beings made from pure energy and living in the center of stars, but it doesn't seem like the place we should start to look for them...
So? Why is this relevant?
Because we are talking about where we should be looking for life. While it may well be possible for "life" to exist in any place imaginable, where we look is determined by what we define as life. The only life that we know exists is carbon based and relies on water. From that we can say firmly that life can possibly exist based on a different carbon-like molecule (silicon) and/or using a different solvent. That is as far as our knowledge of chemistry allows us to extrapolate.
Also, if you think that non-solid life is possible, please provide an explanation on how it would work and why it should be considered life. That's not to say it cannot exist but until your hypothesis has some basis in fact all it is is imagination. If that is all it is, what is the point in seeking it out.
Water is pretty special stuff. It's polar solvent. It has a fairly broad range of temperatures where it exists in a liquid state. It's solid state is less dense than it's liquid state. It can be both an acid and a base under reasonable conditions. It's hard to come up with another substance that would facilitate the complex chemical reactions necessary for any life.
Because we are talking about where we should be looking for life. While it may well be possible for "life" to exist in any place imaginable, where we look is determined by what we define as life. The only life that we know exists is carbon based and relies on water. From that we can say firmly that life can possibly exist based on a different carbon-like molecule (silicon) and/or using a different solvent. That is as far as our knowledge of chemistry allows us to extrapolate.
This is much better said than my posts. We're just talking about probability of finding life, so we should look at locations that seem the most likely to be favorable (liquid solvent, atmosphere, relatively old star, etc) first. I think it's a waste of time either way, but from a purely intellectual standpoint, it's the only way that makes sense.
Write your representatives! Repeal the 2nd Law of Thermodynamics!
I doubt there's very many Biologists throwing around the word 'randomly' like that, since the standard model for evolution is that Mutation is generally random, but selection IS NOT. How complex silicon compounds may get has a lot of bearing on whether selection pressure can matter. (This assumes we are much less likely to find life as it has just begun, before there has been much if any time for selection pressure to affect it - as that's an awfully small window in time compared to the duration of a biome).
Who is John Cabal?
Methane, and Ammonia, are problematic:
Pluses:
1. They are very common, like H2O, around the observed universe.
2. The could work with a Carbon based complex chemistry, at some temperature range.
3. They have solvent properties, also like H2O - you can get many other elements suspended in solutions.
Minuses:
1. They are non-polar, so the ices they form are heavier than the liquid, and sink to the bottom. Hence, Lakes of them freeze from the bottom up and seldom keep any liquid portions during typical models of winter. (see below)
2. They have a narrower range of liquidity, and so even minor climate shifts result in freezing or boiling. Essentially, a planet with methane or ammonia oceans is just about bound to have very harsh winters and summers, unless it has almost no orbital eccentricity or axial tilt.
Who is John Cabal?
First you need to understand why it is there - to control what can an cannot get in or out of the cell (for lack of a better word - without the membrane it wouldn't be a cell).
I understand why it is needed here on earth. But you are refusing to imagine life in the least unlike as we know on earth.
The better for spreading the life to a large volume of an ecosystem, so that sparseness of "nutrition" / consumable energy, is not a problem.
That only works if the life can form in the first place.
This is only a problem if the life cannot form in the first place {end of poor joke}.
Also, if you think that non-solid life is possible, please provide an explanation on how it would work and why it should be considered life
The various constituents, lets say molecules, (if it is in plasma form, there are implausibilities in this scenario that I am about to describe) should stay together. This is because traditionally, "structure" has been considered an important criterion for life. And one good way of having a structure is to start with some adhesion, however loose. Now I think a very vague "structure" should qualify as being sufficient for "life" because the very requirement for having a "structure" was seemingly done to adjust for "life as we know it".
Now, if the "organism" is bathed in a radiation which has a mild ionizing influence upon it such that electrons are knocked off from different constituents and keep getting stuck to other constituents of the same "organism". This would exert a vague electrostatic attraction and we get the cohesion. Occasionally, due to randomness effects, aided by a bit of "wind"/"predator"/shortage of salubrious ionizing radiation, this organism would split, causing "death" / the equivalent of reproduction by something analogous to "cell division".
Surrounding atmosphere is not affected by the radiation because of its chemical composition, but some part of the surrounding atmosphere is "food" / "nutrition", which the organism by some effort, can assimilate into itself. Some molecules always keep getting dropped from the organism due to randomness effects, serving as kind of "humus" / "top soil", though this is all in gaseous form. This is easy food for the next organism of similar kind that strolls by.
Since the organism is assimilating other kinds of molecules into itself, there will some-times be errors/mutations/imperfections in this assimilation process leading to "variation". So somewhat unlike life on earth, reproduction is not the instant when variation from parent(s) happens, but during the lifetime of an "individual", he keeps varying. Metaphorically, the guy is "born a hyacinth and died a zebra".
Bingo Dictionary - Pragmatist, n. A myopic idealist.
That's very well said Mashdar, thanks for this :-)
Silicon doesn't have much in the way of properties that would promote life. It's a nice sci-fi treatment, from maybe the 50's, but it's not realistic chemically for exactly the reason you mentioned. Silicon readily forms a single type of crystal with itself; carbon readily forms millions upon millions of different molecules with all sorts of other elements... especially hydrogen, who has a great way of bonding/not really bonding with itself.
Fascism: An authoritarian and nationalistic right-wing system of government and social organization. See also: NAZI's
If life is just an evolved entity composed of randomly assembled machines, as some biologists claim,
'Some" biologists? Like pretty much all of them.
then it begs the question of wether or not there might be 'life' out there that is not water based, but based on say, sand -- or silicon.
Not likely: nothing even remotely like the diversity of stable organic carbon-based compounds has been observed.
"randomly assembled machines"
There's no professional serious biologist that says that. Darwinism and evolution is NOT "we somehow spontaneously fell together".
these components disperse quickly in a gas
in gas under sea level pressure on earth sure. not so much the case near the "surface" of a gas giant.
Liquid methane is a poor solvent, as is any hydrocarbon. Anyone who has made salad dressing would be able to comprehend that; hydrocarbons tend to separate rather quickly and anything in suspension within them tends to float to the surface or sink to the bottom quickly. Put a cracker into water and into a hydrocarbon, and the water quickly dissolves the cracker while the cracker stays in one piece in the hydrocarbon. Of course, the colder the hydrocarbon, the longer it takes for those things in suspension to drop out. However, while life as we know it needs water as a solvent, it is entirely possible that other alien life-forms may not need to have their necessary nutrients and chemicals suspended in a solvent.
So the general assumption is at times somewhat like - water is needed to have a good chance of life existing somewhere. Somewhat easy to figure out if water exists (or, more like, existed a bazillion years ago) on a remote, newly discovered rock floating around a thermonuclear device.
But no, you must generalize - "Not water, but any liquid solvent ... blah blah ..". Unfortunately, this "any liquid solvent" does not have a particular spectral pattern from which it is simple to figure out if the planet consists of this "any liquid solvent". So mostly, some scientists with limited means, rely on "water" for now. Your generalization is cool.
Since we are theorizing anyway, I generalized it further, especially as a response to your
Of course, a completely arid and barren planet probably wouldn't have the necessary conditions for life to begin (primordial soup and all), so let's not focus there.
But no, absolutely bullshit. I don't have the license to generalize. At this point, you must start talking about "probability" of finding life".
Though I like your "waste of time either way". It is fun only as a purely intellectual pursuit.
Bingo Dictionary - Pragmatist, n. A myopic idealist.
The author wasn't talking about how life only occupies a tiny sliver of the planet as a whole. Duh, most of the planet is molten iron.
The author was talking about how life only occupies a tiny sliver of the areas of the planet that do or could contain significant amounts of water.
And the O.P. was saying, rightly I think, that this isn't true. Everywhere there's water on this planet, there's life. There might be a tiny sliver that doesn't have life, but that's okay, because astronomers aren't assuming that water necessarily means life anyway.
The enemies of Democracy are
Of course, a completely arid and barren planet probably wouldn't have the necessary conditions for life to begin (primordial soup and all), so let's not focus there.
But no, absolutely bullshit. I don't have the license to generalize. At this point, you must start talking about "probability" of finding life".
Right, my quote should have had the word "likely" or "expected". The point being, if we're going to look for life we might as well focus our search on life similar to the only other life we are aware of. At least we know that life can be based on carbon and water. If it's a crap shoot anyway, might as well bet on the one we know is possible.
Though I like your "waste of time either way". It is fun only as a purely intellectual pursuit.
Yup.
Write your representatives! Repeal the 2nd Law of Thermodynamics!
But since it's the only one we've ever found, I suppose your point more readily supports the view that we are alone in the universe.
Personally, thanks to Hawking's reasoning that's what I'm hoping for (paraphrased): There is probably life out there, but if they know where we are we're fucked.
The reasoning being that any form of life sufficiently advanced to detect us here on Earth has probably already consumed, or is close to consuming, the resources on their own home planet. Given that we will be little more than cave-men to such creatures, a mutually beneficial relationship would be impossible because we would have nothing to offer but our raw resources, which they could take quite easily. If they are extremely advanced, then they've probably been wiping out planets and consuming all the resources for millennia. It's just the natural course of evolution. See Battlefield Earth, Independence Day, and War of the Worlds for relevant fiction.
The best case scenario is if we are the most advanced civilization in the universe. It's not likely, but we can hope. Just to be safe though, we should shut down SETI immediately - those damn hippies are going to get us all killed!
Security is mostly a superstition... Avoiding danger is no safer in the long run than outright exposure. - Helen Keller
I didn't say it was a good solvent, only that it might work. Besides, saying that anyone who has made salad dressing knows that is simply false - the reason it separates is because the fat does not mix with water and most of what is in salad dressing is water-based. Also, the fact that fats do not mix well with water-based things has no bearing on the properties of hydrocarbons in general. The cracker example is a poor one - it is made specifically to eat so is pretty much designed to dissolve in water - the fact that it doesn't dissolve in a random unspecified hydrocarbon (presumably oil again) is irrelevant. There are many types of hydrocarbon, and the properties are highly dependent on their structure. Perhaps methane was a poor choice (I'm sure I've heard it speculated that life could use methane as a solvent though) but not simply because it is a hydrocarbon. Turpentine for example is clearly good solvent of some things, and it is made up of hydrocarbons. Who is to say that things which DO dissolve in liquid methane cannot be used as the basis for life as energy storage or whatever?
But no, you must generalize - "Not water, but any liquid solvent ... blah blah ..". Unfortunately, this "any liquid solvent" does not have a particular spectral pattern from which it is simple to figure out if the planet consists of this "any liquid solvent".
Any liquid solvent does not work. Water is unique in the universe, it has hundreds of properties that, as far as we can tell, are absolutely essential.
For just one example, think about ice. Water is one of only five substances known to be less dense as a solid than a liquid. The others are gallium, bismuth, germanium, and silicon. Now imagine what would happen if ice didn't float in water, but instead sank, like most solids do when placed in their liquid counterpart. First a crust will form, held up by the moderate surface tension of water (another unique and important property). This will probably look pretty similar to a thin layer of normal ice. However, as the crust grows it will eventually become too heavy and sink, crushing much life in the lake. Worse, the layer of ice that normally forms over water acts as insulation, allowing only a few feet of water to freeze. Without that insulating layer, a new crust forms, then sinks, then forms, then sinks, until the entire lake is frozen, destroying any life in the lake.
It's not just that we only know water, so that's what we look for, it's that we haven't been able to come up with a scenario where anything other than water can be used. So far as we can tell, no other solvent even has the potential of replacing water. The only forms of life that are non-water and carbon based that we can imagine are also forms of life that we would be impossible to recognize.
For example, a nebula could be an exotic form of life that we aren't even capable of recognizing as life, or our solar system could be alive but operates on such time scales that render us completely incapable of detecting them.
As far as life on planets though, the only sort of life that we can come up with that could exist uses at the very least water, for all its unique properties that are so ideal for the formation of life. A process that would allow life on a gas giant, for example, we are not yet capable of recognizing as a process needed for life. So we stick with what we do know. How are you supposed to look for something you don't know? If I say "Go find me some diddlyhoogits", you're going to say "What the hell is a diddlyhoogit, at what does it look like?" You can't look for something unless you know what to look for, otherwise it's just blind stinking luck, and we're just as likely to find life that way while looking at other stuff.
We know for sure that water fits the bill for life, and we've already found life in extreme conditions here on earth - basically anything with an energy source and you'll find life here, so when we go looking we look for the conditions we know produce life. We don't go looking for conditions that we have no idea if they produce life or not.
Looking for planets with silicon gets us no-where closer to our goal, looking for planets with water does.
Security is mostly a superstition... Avoiding danger is no safer in the long run than outright exposure. - Helen Keller
'Some" biologists? Like pretty much all of them.
Name one, and you better have a quote where he says it's completely random like that.
Security is mostly a superstition... Avoiding danger is no safer in the long run than outright exposure. - Helen Keller
Hehe, the "ugly bags of water" episode was one of my favorites, and very fitting for the discussion.
Security is mostly a superstition... Avoiding danger is no safer in the long run than outright exposure. - Helen Keller
but any planet in an appropriate place makes at least a bit of sense to check.
And what exactly are you checking for? We can't exactly get surface resolution on the majority of the Earth-sized satellites in our own solar system, and we've yet to come up with any other set of substances that are conducive to life other than water and carbon. Most planets outside our solar system we can't even detect directly. You have to have something broad to look for, otherwise what you see in a planet will tell you absolutely nothing about whether or not there is life there, yet you want us to look for something other than water? What exactly?
Finding anything other than water and carbon tell us zilch about the possibility of life. Water and carbon tell us the main ingredients in the only recipe for life we know of are there, and so it's worth looking closer at such a body. Nothing else gives us that much to go on. Nothing else gives us anything to go on at all, unless our understanding of how life can form fundamentally changes.
Security is mostly a superstition... Avoiding danger is no safer in the long run than outright exposure. - Helen Keller
It was the other guy who was saying any liquid solvent works. Maybe you have jumped into this thread without understanding what is going on?
Bingo Dictionary - Pragmatist, n. A myopic idealist.
As I remember it life pretty much summed up the obvious with Viruses being on the border.
Bacteria is pretty spread out, I would like to see this small silver view, as even Ice tends to have a batteria infestation.
If we include other planets perhaps, but then we have found bateria in space, possibly on marse, I am not following how follow the water is bad.
If a planet has water it is more likely to develop and maintain life as we know it.
Optionally I say follow the dart, this is the method where scientists throw darts at star charts, and then go to where the dart is, odds are if the dart lands in a place not occupied by an obvious star, there is a galaxy by it, and high chance that life exists in the galaxy.
So if it is an environment where we can actually hope to OBSERVE liquid water
That's the real problem here - with current technology we can't even tell whether or not there is liquid water on other planets in our own solar system which is capable of sustaining life, even when we send out probes to within a few thousand miles or rovers onto the surface.
We've mapped Mars reasonably well, with direct observation - even landing on the planet, yet we cannot rule out the possibility of life yet. How could we do so for say, Venus, who's surface we can't even observe, yet has tons and tons of energy (granted, maybe too much energy) that would be great for life? Or Europa, which has an ice crust, yet may be generating enough energy via tidal forces with Jupiter to allow for life?
The problem isn't that looking for water is a bad guide, the problem is we need to find liquid water, which is friggin hard.
Security is mostly a superstition... Avoiding danger is no safer in the long run than outright exposure. - Helen Keller
... no? I said water is the perfect thing to look for, and that the article assumes that water doesn't matter. I was simply stating that indeed it does. I mean, they expect us to look for life in the upper-atmosphere and inner-mantle. What the hell are they, nuts?
I bet we could seed the atmosphere of venus with some of the appropriate extremophiles (for the atmosphere anyways), and give it 50-100 years it would start changing. And we should look for something on mars that will allow us to create a thick atmosphere there, so it can be habitable one day. It might not be the only kind of life though, we might also someday discover life in all kinds of places, just not like ours.
Where is the mod rating for "scary"? Also,
You and I are "evolved entities composed of randomly assembled machines". That's just an elementary fact of biology. The "randomly assembled machines" part doesn't even bear on evolution, we'd be "randomly assembled machines" even if creationism were true.
Nice hidden reference there to the biblical creation myth.
Uggg, I looked at your link.
It said:
A simple example would be "I think he is unattractive because he is ugly." The adjective "ugly" does not explain why the subject is "unattractive"
Then it says:
To beg the question does not mean "to raise the question." (e.g. "It begs the question, why is he so dumb?") This is a common error of usage made by those who mistake the word "question" in the phrase to refer to a literal question.
Why did they change the example from ugly to dumb? Wouldn't the original example beg the question, "Why is he so ugly?"
I must be fucking dumb, because I didn't understand shit from your link.
How many more years will slashdot have an off-by-one error on your Score in your profile?
Yes, it is. Every single time I have heard the phrase used — whether on TV, in magazines, in newspapers or in casual conversation — that is exactly what it has meant. The only exception is people "correcting" others on Slashdot.
Page on Internet is wrong. Just because a phrase has a specific meaning in one particular field (debate, in this case) does not mean it cannot have another meaning in everyday conversation.
Igor Presnyakov stole my hat
Here is a longer explanation.
http://en.wikipedia.org/wiki/Begging_the_question
If Slashdot were chemistry it would look like this:Cadaverine
As we know that life should use DNA or RNA and that certain genes are patented, the rule is as follows:"looking for aliens follow copyrights".
... we should shut down SETI immediately ...
Nah; it wouldn't help. First, SETI, is primarily listening, not broadcasting, so it isn't telling any aliens very about us. But the important thing is that we have been broadcasting our existence to the universe for around 90 years now. All of our radio, television, and radar has been radiating a very signal that has been expanding in a sphere for that longy. This isn't a very big volume as the universe (or even the galaxy) goes, but it does contain few thousand stars. And more to the point, it could contain an unknown number of little, invisible monitoring gadgets that are listening for "unnatural" signals.
There have been a number of articles written by astronomers, explaining that our signal would easily be detectable within the volume by our own current technology, and any astronomers within at least 60 or 70 light years would be able to pinpoint our star, determine (from the Doppler shifts) how far our planet is from the sun, and infer likely properties of our planet and technology.
So the damage has long since been done, primarily by the commercial TV industry and the military radar installations. SETI isn't important in comparison. But it just might give us advanced warning if someone is heading our way, so we might as well keep it running.
Those who do study history are doomed to stand helplessly by while everyone else repeats it.
Ok, I think I'm figuring it out now.
In the example:
A simple example would be "I think he is unattractive because he is ugly." The adjective "ugly" does not explain why the subject is "unattractive"
That begs the question. Meaning, the premise has not been proved. So, I think it might be correct to say, "This begs the question: why is he ugly/unattractive?". But, Starcub meant to say, "this raises another question."
How many more years will slashdot have an off-by-one error on your Score in your profile?