Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Fluid_thinker on 27/05/2015 14:24:32
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This seems to be a matter of opinion as a naive person interested in Physics.
Some things such as Dark Matter, Dark Energy, have variables in the 'Goldilocks' just right zone.
A tad higher or lower and the universe would not have expanded at just the right rate for life as we know it to exist.
Is there a scientific belief that this balance is by some fundamental reasoning or hat it is a happy accident?
Views?
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As another non-scientist I am inclined to take the "agnostic" view that we don't know, and probably cannot know. Science proposes various ideas, such as multiple universes, bouncing universes etc. and one day, someone may come up with "proof" one way or the other.
In the meantime, agnostics of the world unite; we may never be right, but as long as we don't know, we'll never be wrong either. [:)]
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There is an awful lot of universe and very little life, so the answer is "yes".
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This seems to be a matter of opinion as a naive person interested in Physics.
Some things such as Dark Matter, Dark Energy, have variables in the 'Goldilocks' just right zone.
A tad higher or lower and the universe would not have expanded at just the right rate for life as we know it to exist.
Is there a scientific belief that this balance is by some fundamental reasoning or hat it is a happy accident?
Views?
It's not yet known whether those parameters which seem to make the universe fine-tuned for life vary from place to place in the universe. For all we know we're merely in that place in the universe where life was able to arise due to the perfect variation of those parameters.
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There is an awful lot of universe and very little life....
Might this not be based on very limited knowledge of what could be just a vanishingly small part of the universe?
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the universe fine-tuned for life
I tend to think the reverse - life is fine-tuned for the universe.
But a sample size of 1 Planet & 1 Moon is not enough for a prediction!
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The late-great Douglas Adams had an interesting view on this.
http://www.goodreads.com/quotes/70827-this-is-rather-as-if-you-imagine-a-puddle-waking
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Damn! I can't get the "modify" function to work. Never mind.
“This is rather as if you imagine a puddle waking up one morning and thinking, 'This is an interesting world I find myself in — an interesting hole I find myself in — fits me rather neatly, doesn't it? In fact it fits me staggeringly well, must have been made to have me in it!' This is such a powerful idea that as the sun rises in the sky and the air heats up and as, gradually, the puddle gets smaller and smaller, frantically hanging on to the notion that everything's going to be alright, because this world was meant to have him in it, was built to have him in it; so the moment he disappears catches him rather by surprise. I think this may be something we need to be on the watch out for.”
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I tend to think the reverse - life is fine-tuned for the universe.
Why?
What that would literally mean is that life came along and then adjusted itself to be suited for the universe as it is. But that assumes the existence of life to begin with making it a circular argument.
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There is an awful lot of universe and very little life....
Might this not be based on very limited knowledge of what could be just a vanishingly small part of the universe?
Basic statistical analysis of unknowns: assume that the evidence you have is close to the average.
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life came along and then adjusted itself to be suited for the universe as it is
The one constant in this universe is change.
On the small scale (generations), those individuals which better suit the new, changed, conditions tend to thrive better than those which don't. In this sense, life fine-tunes itself for the universe in which it finds itself.
One of the most general characteristics of life is that it causes a more rapid global increase in entropy in order to cause a temporary, local, reduction in entropy.
On the larger scale (eons), we see massive increases in entropy throughout the universe. Some of these large-scale increases may hide small pockets of locally-reduced entropy. In such cases, life would be adapted to the universe in which it finds itself.
I would call this a hypothesis based on speculation, since we have such a small stock of samples from which to draw conclusions. We haven't properly explored even 1% of our own planet, let alone our Solar System.
If we did run across Mr Spock's "Life, but not as we know it", I fear we would run right across it and kill it, without even noticing.
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Basic statistical analysis of unknowns: assume that the evidence you have is close to the average.
About a month ago I had cause, briefly, to intrude on a local meeting of Liberal Democrats. Had I counted the number of Lib Dem supporters and extrapolated that figure to the whole country, I would have made a very poor prediction of the outcome of the election. There are times when statistical analysis has to be subjected to a little reality.
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Poor statistical reasoning. A party meeting is not a representative sample. We know that the country is divided into constituencies, each with its own flavor, and the FPP system guarantees that an a priori meaningful "average" requires a very large number of good samples, with very large corrections for tribal loyalty, tactical voting, and weather. So difficult, indeed, that no professional got it right, and the country is now ruled by a woman who wasn't even a candidate!
If you found, say, 20 LibDems in one room and none anywhere else in the constituency, you would confidently conclude that they were doomed in Muckshire East, and it would be reasonable to speculate that their support elsewhere was weak.
To the best of my knowledge there is no life elsewhere in the solar system, which is a very large constituency. I therefore confidently state that nearly all of the solar system is inhospitable, and if it were reasonably representative of all such planetary systems, we'd expect to find pretty much the same sparse distribution around other stars. But we know even that condition isn't met: most of the universe is indeed inhospitable to life.
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Poor statistical reasoning. A party meeting is not a representative sample
Of course it’s not. I know that, and so do you. However, if by some absurd quirk of circumstance you knew nothing of the world outside that room, you would be unable to reason as you did. Our observable Universe is indeed vast and, arguably, mostly devoid of life, but it may be no more representative of the entire cosmos than a small roomful of Lib Dems is representative of the voting populace of the UK.
I would not seek to argue with the fact that cosmologists have to accept some generalisations in order to make any progress, but all they can really achieve is knowledge about our Universe. All the rest is supposition.
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To the best of my knowledge there is no life elsewhere in the solar system, which is a very large constituency.
I think we are all trapped by the "Life as we know it" paradox. You can't really see something until you know it is there.
- "Life as we know it" is based on water-soluble carbon compounds, driven by instructions encoded in DNA (and, at least temporarily, in RNA).
- This immediately limits "Life as we know it" to the range of temperatures where water is liquid, ie a bit below 0C (salty water in polar conditions) to a bit over 100C (in the cooling water of a nuclear reactor).
- ie Mars is probably too cool, and Venus is definitely too hot!
- It also limits life to conditions where the atmospheric pressure is high enough to support liquid water; not so low that ice sublimates, and not so high that all water is compressed to ice.
- ie the Moon, Mercury, Comets and Asteroids are far too low, while Mars is a bit too low; pressure on gas giants like Jupiter and Uranus is far too high.
- So it is safe for you to say that "Life as we know it" does not exist on the surface of planets in our Solar System, outside Earth.
In recent years, we have found microorganisms (Life as we already know it):
- seeding ice crystals in high-altitude clouds
- living in hot springs near the boiling point of water
- living off radioactive decay at the bottom of our deepest goldmine
- in the high neutron flux of a nuclear reactor
- with properties of eukaryotes & prokaryotes, living near the mid-ocean ridge
- we can still only culture a few percent of the bacteria in our environment (including those in our micro biome, and our back yards). We can only really identify them due to the extreme sensitivity of the PCR (http://en.wikipedia.org/wiki/Polymerase_chain_reaction) technique.
- a recent survey of DNA in the sea found huge viruses that nobody expected to find
- so there is life everywhere we have looked for it on Earth.
- there is serious investigation of the possibility of relics of Life under the surface of Mars
- speculation about life in the liquid water cores of icy moons like Enceladus and Europa
- But if they aren't based on DNA or RNA, we would have trouble finding them (PCR won't work).
The problem is, if we found "Life, but not as we know it", I doubt we would recognise it immediately, on Earth, or anywhere in our Solar System.
I would look for life in zones where there is considerable available energy being released by some process, so that Life could tap off a small fraction of the available flow of energy, in order to reduce its local entropy. It could well be associated with some form of boundary between different conditions, as it is easier to siphon off energy if you have two adjacent zones with very different conditions. (Consider the temperature difference powering Carnot's heat engines, the charge/pH difference powering proton-eating bacteria in swamps, etc)
At this point, we are out of the realms of science experience, and into the realms of science speculation. Some do this more effectively than others, but the group historically least inhibited about science speculation is probably science fiction authors.
Drawing on their imaginings, we could speculate about "Life as we don't know it":
- Silicate-based life in the Earth's mantle
- Carbon (diamond)-based life 100-150km below our feet
- Metallic life at the Earth's solid/liquid core boundary
- Hydrocarbon-based life in Titan's Ethane lakes,
- Life in magnetic fields on the Sun
- Life at Mercury's poles
- Life in in the hot sulphuric acid rain of Venus
- Life in the atmosphere of Jupiter
- Life in the black organic coating of Comets and Pluto
- Superconducting life in the Oort Cloud
If we found "Life, but not as we know it", I doubt we would recognise it immediately, on Earth, or anywhere in our Solar System; even worse, we would probably eat it, drink it, breathe it, poison it, mine it, burn it or build our houses out of it.
In "Hitch-hikers Guide to the Galaxy", Douglas Adams parodied a human-centric respect for life in imagining Arthur Dent, already traumatised by the demolition of his house to make way for a highway bypass, promptly experiencing the demolition of the Earth to make way for a hyperspace bypass.
Humans tend to be rather egocentric, in a universe which I see as not being very human-centric.
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Neither one nor the other is tuned. There is no tuner.
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I would not seek to argue with the fact that cosmologists have to accept some generalisations in order to make any progress, but all they can really achieve is knowledge about our Universe. All the rest is supposition.
The question was about the universe. You might imagine another universe that could be teeming with life of any form you like, but it would be wholly irrelevant to the question or to any denizen of this universe.
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I have a pet theory that the Universe is life. This is maybe because of the coincidence that everything in the Universe could be described from a biological perspective eg. the Universe is born, the neural like network of matter and dark matter, the evolving Universe.
Yes I know it's pretty far fetched but until someone proves me wrong I'm happy to linger on the thought that maybe the Universe itself is a happy accident of life. [:o]
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…but all they can really achieve is knowledge about our Universe. All the rest is supposition.
You might imagine another universe that could be teeming with life of any form you like, but it would be wholly irrelevant to the question or to any denizen of this universe.
Agreement??? One of us is slipping!