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Topic: Do you believe in the death of Universe? (Read 2821 times) |
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Ajax
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Do you believe in the death of Universe?
« on: Jun 2nd, 2005, 12:27am » |
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In this forum I have found people from different countries, cultures, having diverse ways of thinking and religions; and of course with scientific education. I believe this will help me to leave some prejudices I have and learn more about the place we all live.
In this thread, my intention is to start a conversation in a more philosophical basis than scientific. Facts and figures are welcome here, but I would mostly like to see what your feelings and thoughts are.
According to the second thermodynamic law, there is always the tendency to move in a lesser form of energy (with heat being the “worse”, excuse me if I didn't manage to translate it well in english). If we accept that there is no external or an “exotic” unknown form of power, and that universe started from a big bang and since then is expanding, after several years (ok, maybe some trillions), all the energy will have been eventually transformed into heat, thus unable to transform into anything else (Absolute entropy, Heat death of the universe). Being, if not atheist, at least agnostic, I find this scenario very dark. The human race may some day become extinct, giving the way to some other species to evolve. Maybe we’ll destroy ourselves way before the sun die or we realise what we’re doing. I don’t really mind about that. I’m sure that there are other logical species out there to keep intelligent life existing. But what if everything ends in a total null? Will have everything happened in vain? I don’t like such a scenario.
Please write down your thoughts, be as simple as you can. Thanks 
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towr
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Re: Do you believe in the death of Universe?
« Reply #1 on: Jun 2nd, 2005, 1:47am » |
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I have my doubts the human race will live to even come close to experiencing the heat death of the universe.
But anyway.
I don't see a reason why there couldn't be a second Big Bang (somewhere), the first one happened pretty much out of the blue it seems. Now if this is the case, there might be a chance to escape to a new 'universe' before this one dies. (On the other hand, it might blow us up  )
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SMQ
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Re: Do you believe in the death of Universe?
« Reply #2 on: Jun 2nd, 2005, 6:30am » |
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Hmm, while I myself am religious, even if I'm deluded and your scenario is the way things will ultimately be, I don't see that everything that happened will be in vain.
If you've lived well, loved well, striven to be the best you possible, and left the small parts of the universe you touched generally better than when you found them, what does it matter if the future remembers?
The Universe is sparklingly alive with consciousness--whether it's only our own little speck or billions upon billions of scattered specks--to quote a like from Babylon 5, we are the Universe trying to understand itself. And, whether it ultimately takes the course of nature as we now understand it and experiences its own old age and eventual death writ large, or is transformed into something wonderfully different, you've still been a part of the glory of the infinite--what more could one really ask?
--SMQ
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rmsgrey
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Re: Do you believe in the death of Universe?
« Reply #3 on: Jun 2nd, 2005, 7:44am » |
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Larry Niven made the point that the 2nd Law of Thermodynamics could be paraphrased as "water runs downhill" - something so obvious that we don't stop and think about where the water at the top of the hill comes from. On the other hand, all our common sense experience is with low entropy situations where entropy is (relatively) rapidly increasing - rapidly enough that small eddies of decreasing entropy (like us) can exist. We have no real intuitiion for what a high-entropy low-flux universe would be like. Among other things, the direction of time as we percieve it is closely tied to the direction increasing entropy - at maximal entropy, you will get transient pockets of lowered entropy - which is one possible explanation for our universe.
Even if you accept that the universe is doomed to the eventual winding down of the cosmic clockwork (the ultimate in flat batteries) there's still a few loopholes that would allow something recognisably human to survive - as towr pointed out, it may be possible to find another universe in time, or it may actually be possible to sustain something like life from the small variations in the maximal entropy state (though you're looking at something "indistinguishable from magic" to even have a hope of doing that), or there's the possibility that human consciousness can transcend this reality - the possibility of an immortal soul.
Even if all life ends in death, and the final night endures forever, then still what is now will always have been. What we are - everything we do - is. Even if we have no future, no purpose beyond ourselves, our existence has meaning and purpose as long as we give it meaning and purpose. What we do may not reach beyond ourselves, but we know it reaches at least that far. The long night may be cold and dark, but here is warmth and firelight and music and laughter.
If you haven't read it, Olaf Stapledon's "Star Maker" touches heavily on the issue of the purpose of the universe.
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JiNbOtAk
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Re: Do you believe in the death of Universe?
« Reply #4 on: Jul 1st, 2005, 3:32am » |
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I personally believe that the universe would come to an end. It might be due to heat death, as Ajax put it, or maybe some other factors that we have yet to discover. However, being the incredible optimist that I am,  , I'd rather think that this death of the universe would give birth to another 'universe' ( whatever that might be ). From what little I understand of the Big Bang theory, the universe is expanding, and would do so for several years to come ( okay, trillions. ) The death of the universe would then occur when it starts to contract ( the Big Crunch ). What I'm wondering is, when the contraction starts, what happened to the space where part of universe once was ? What occupies it ?
Now I'm having a headache
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rmsgrey
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Re: Do you believe in the death of Universe?
« Reply #5 on: Jul 1st, 2005, 4:41am » |
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on Jul 1st, 2005, 3:32am, JiNbOtAk wrote:| What I'm wondering is, when the contraction starts, what happened to the space where part of universe once was ? What occupies it ? |
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A better question might be "Is there any space outside the universe?" It's possible that space and time are both consequences of the presence of mass - that the space within the universe is caused by the separation of the objects within it.
As far as I'm aware, saying that the universe is very large is the same as saying that the Planck Length is very small - the only scale we have for measuring the universe is the granularity of its fabric. If, instead of imagining the universe shrinking down, you imagine everything in the universe expanding (assuming it does so in a way that doesn't run into square-cube law problems) then you don't run into the problem of vacating regions of whatever is "outside" - One of the cuter cosmological images I've encounered is the possibility that all fundamental particles (hypothetically being point singularities) are actually embedded universes - that every electron is, from the inside, an entire universe, potentially larger than our own.
(how's the headache getting on?)
*************************************
A quote from Babylon 5 that seems loosely related to the original topic (and is pretty much the only redeeming feature of "Infection" - the episode it's in):
"Ask ten different scientists about the environment, population control, genetics - and you'll get ten different answers. But there's one thing every scientist on the planet agrees on: whether it happens in a hundred years, or a thousand years, or a million years, eventually our sun will grow cold, and go out."
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Icarus
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Re: Do you believe in the death of Universe?
« Reply #6 on: Jul 1st, 2005, 3:49pm » |
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As I've grown older, I've lost my appetite for meaningless speculation. The concept that subatomic particles are embedded cosmologies of their own is exactly this. Unless there is some means to test the idea, some way in which our universe would behave differently were it true, there is no point to it.
As far as the Big Crunch goes, evidence is severely against it at this time. The expansion rate of the universe is actually increasing - meaning it is flying apart even faster than in the past. Unless there is some totally unforeseen mechanism to counter this, the universe will continue to fly apart forever. Barring outside interference such as religious people (including myself) expect, this leaves Heat Death as the ultimate outcome of the universe.
However, as someone (I don't remember who right now) explained in another thread, because of quantum effects, occasional imbalances in the energy spread will form, allowing energy to flow once again. For the most part these will be incredibly small, and will quickly return to a maximal entropy state. However, there is an incredibly small probability of a truly huge imbalance forming, even as big as our universe or bigger. Such an imbalance effectively would be the "Big Bang" of a new universe. While the probability of this is mind-bogglingly small, with an infinite amount of time to deal with, it becomes an almost certainty that it will happen.
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JocK
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Re: Do you believe in the death of Universe?
« Reply #7 on: Jul 2nd, 2005, 4:41pm » |
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Heath and entropy are of course not the same thing, and I doubt whether the term "heath death" gives a correct description of the fate of our universe.
The universe started from an ultra-low entropy (i.e. highly unlikely) big bang. (The reminiscent of this low-entropy starting point is the homogeneous cosmic background radiation.) Despite this low-entropic starting point, one thing is certain: unless Icarus' Deus ex Machina intervenes, we will end in a high entropy (i.e. highly likely) universe.
How does a high-entropy universe look like? We can make a pretty good guess about this as we know that there is a theoretical limit to the amount of entropy that can be reached within a given region. From observation we know that some spatial regions of our universe have reached this maximum entropy already. The entropy of these regions is so immense that, although the volume of these regions is ultra small compared to the volume of the universe, the vast majority of the total entropy of our universe is already contained in these tiny spatial regions.
These spatial regions of maximum entropy are commonly referred to as black holes.
The radius of a black hole is proportional to its mass, and the entropy of a black hole is proportional to its surface area. As a result, when two black holes of equal mass merge, the result is a doubling of the total entropy and a quadrupling of the total 'black hole volume'. So, the entropy of the universe will continue to increase by the formation of new black holes and the merger of existing black holes so that more and more space will reach the state of maximum entropy. The logical end would be all mass being sucked into one ultra-high entropy chaotic black hole of gigantic size. When this has happened, the whole universe has reached the state of maximum entropy. *
I don't see how this in any way would / should impact any (religious) beliefs about the existence of a non-material reality that goes beyond physics.
* This state should not be confused with the state that would result from the so-called big crunch scenario that would cause the whole university to shrink into a point. Actually, the size of a black hole containing the mass of the whole universe would be huge: our own galaxy would fit into it like a grain of sand would fit into a cathedral. An interesting exercise is to calculate the mass density of this final black hole. Leave that as a problem for you guys to solve...  (The answer will surprise you! For those who want to do an accurate calculation: the radius R of a black hole results from equating the potential energy of an object of mass m captured in the gravitational field of a black hole with mass M - G.m.M/R - to the non-relativistic kinetic energy m.c2/2 with c denoting the speed of light.)
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| « Last Edit: Jul 3rd, 2005, 5:40am by JocK » |
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rmsgrey
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Re: Do you believe in the death of Universe?
« Reply #8 on: Jul 3rd, 2005, 12:49pm » |
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My understanding of the most probable "heat death" scenario is one where a number of small local concentrations of mass/energy are expanding away from each other at sufficient speed that they'll never meet each other. My understanding of the merging black holes scenario is that it represents a "closed" universe and the eventual "Big Crunch"
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towr
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Re: Do you believe in the death of Universe?
« Reply #9 on: Jul 3rd, 2005, 3:24pm » |
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Merging black holes does imply a big crunch. Because frankly it doesn't matter whether you have a planet/star/cluster with a certain mass at some point, or an equally heavy black hole.
So if the universe doesn't crunch, the black holes can't all merge either.
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JocK
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Re: Do you believe in the death of Universe?
« Reply #10 on: Jul 3rd, 2005, 4:11pm » |
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We should be careful with the use of the term "big crunch". I'm not a cosmologist, and certainly not a specialist in solving Einsteins equations of gravity, but my understanding is that the big crunch implies the shrinking of all space-time metrics into a singularity. Time, space and the whole universe simply cease to exist.
Such is not the case with a universe in which all mass has been absorbed in black holes, and in which the black holes start merging. The universe simply reaches a high-entropy state that you could describe as an equilibrium state.
In theory it could be possible that whilst all mass has been absorbed into black holes, these black holes never merge into one due to the continuous expansion of the universe. However, such is not very relevant to the life forms 'captured' behind gravitational event horizons, and hence neither relevant to this discussion.
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| « Last Edit: Jul 3rd, 2005, 4:35pm by JocK » |
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JiNbOtAk
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Re: Do you believe in the death of Universe?
« Reply #11 on: Jul 3rd, 2005, 8:58pm » |
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Correct me if I'm wrong, but what I understand from what Jock said is that rather then the Big Crunch happenning by the universe contracting, it would happen by the expansion of black holes. The black holes would expand by merging with other black holes, up to a point that the rate of black holes merging is higher than the universe expansion rate. Right ?
However, a higher entropy would mean a higher amount of disorder. If the universe is to reach a high-entropy state, how could it be in equilibrium, since there is so much disorder ? What would the final state then be ?
rmsgrey; the headache seems to get just a tad worse, must be due to increasing entropy.
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Ajax
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Re: Do you believe in the death of Universe?
« Reply #12 on: Jul 4th, 2005, 12:31am » |
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I'm glad to see that there are so many different opinions (although rather similar). To put it further, let's try and understand what means to have all matter in one single place (I mean in the beginning). What was there actually before that? Which question is actually greater, what is after the end or what was before the beginning?
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Re: Do you believe in the death of Universe?
« Reply #13 on: Jul 4th, 2005, 2:26am » |
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on Jul 4th, 2005, 12:31am, Ajax wrote:| Which question is actually greater, what is after the end or what was before the beginning? |
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Let me add another question to that; Is what before the beginning the same as what is after the end ?
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Re: Do you believe in the death of Universe?
« Reply #14 on: Jul 4th, 2005, 4:13am » |
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The taughest question is: what lies in between?
And the answer is: 42
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Barukh
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Re: Do you believe in the death of Universe?
« Reply #15 on: Jul 4th, 2005, 4:42am » |
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Because this discussion considered the destiny of black holes, let me add my 2 cents.
In 1974, the famous British physicist Hawking developed a theory where considered black holes not to be everlasting objects: by emitting radio-waves they "evaporate" over time proportional to cubes of their masses. For instance, a black hole with 10M mass will evaporate in 1067 years. 
This theory remains controversial.
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JocK
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Re: Do you believe in the death of Universe?
« Reply #16 on: Jul 4th, 2005, 1:10pm » |
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on Jul 3rd, 2005, 8:58pm, JiNbOtAk wrote:
However, a higher entropy would mean a higher amount of disorder. If the universe is to reach a high-entropy state, how could it be in equilibrium, since there is so much disorder ? What would the final state then be ?
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Equilibrium = disorder = high entropy.
(I know this from experience: if I let my kitchen evolve without any intervention, in a few days time it's a complete mess. )
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solving abstract problems is like sex: it may occasionally have some practical use, but that is not why we do it.
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JiNbOtAk
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Re: Do you believe in the death of Universe?
« Reply #17 on: Jul 4th, 2005, 8:50pm » |
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on Jul 4th, 2005, 1:10pm, JocK wrote:
Equilibrium = disorder = high entropy.
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My bad, I had this preconceived notion that an equilibrium state should be a high ordered ( low entropy ) state. There's always the chance that everything everywhere would be in disorder, but still be in equilibrium.
On another note, Grimbal, what do you mean ?
on Jul 4th, 2005, 4:13am, Grimbal wrote:The taughest question is: what lies in between?
And the answer is: 42 |
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And if Hawking is right, does that mean all that is going to be left of our universe radio waves ? I personally find that hard to believe.
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Ajax
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Re: Do you believe in the death of Universe?
« Reply #18 on: Jul 5th, 2005, 2:43am » |
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I just had a revelation: Murphy's law comes from the second thermodynamic law...
Jinbotak, as for your wondering for the number 42, it is all written in the great saga The Hitchhiker's guide to the galaxy by Douglas Adams.
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| « Last Edit: Jul 5th, 2005, 3:25am by Ajax » |
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Icarus
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Re: Do you believe in the death of Universe?
« Reply #19 on: Jul 5th, 2005, 6:15pm » |
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on Jul 4th, 2005, 1:10pm, JocK wrote:| Equilibrium = disorder = high entropy |
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Despite common perceptions, entropy is not the same as disorder. Maximal entropy states tend to be highly ordered. Entropy is a measure of how evenly energy is distributed. Maximal entropy occurs when energy is distributed as evenly as possible. This is usually a very well ordered state.
The perceived relation between entropy and disorder comes about in that in our common experience of relatively low entropy systems, highly ordered states are more likely to have energy concentrated in certain well defined regions, whereas the chaos of disordered states tends to spread it around more. But as you move towards high entropy, the opposite situation becomes more common: chaos opens up discrepancies in energy distribution, while order spreads it evenly.
I have long since come to believe that when the equation dQ = -TdS, and concept of entropy, was discovered, they should have chosen the opposite sign, and defined a concept that is the opposite of entropy. (Ajax - what greek word would you choose or make up to mean the opposite of entropy?) This concept could then be used ACCURATELY in the same sense that "energy" is commonly used in popular discussion today. It would be something used up by processes as they occur, and its eventual loss (the zero-point of this quantity would be defined as the maximal entropy state) would be what brings the process to a stop. It would be easy to explain "Heat Death": Our universe was embued with a certain amount of this anti-entropy at its creation. When it is all gone, the universe will cease to "run".
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| « Last Edit: Jul 5th, 2005, 6:25pm by Icarus » |
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Ajax
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Re: Do you believe in the death of Universe?
« Reply #20 on: Jul 6th, 2005, 3:39am » |
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Ok, first of all some facts that I came up with for this discussion:
Quoting from Rudolf Clausius (1880):
I prefer going to the ancient languages for the names of important scientific quantities, so that they mean the same thing in all living tongues. I propose, accordingly, to call S the entropy of a body, after the Greek word "transformation". I have designedly coined the word entropy to be similar to energy, for these two quantities are so analogous in their physical significance, that an analogy of denominations seems to me helpful.
Funnily, in modern greek ntropy (no e in front but with the same roots) means shame and shyness (two meanings).
Icarus, if I have understood well, what you suggest as the present meaning of entropy is the tendency of "horizontal" arrangement (better say flattening) of everything inside a system. A desert full of sand with no dunes (perfectly flat) is a place with no chance of changing to anything better, however it is in perfect order and homogeneity.
As for your question about "what greek word I would choose or make up to mean the opposite of entropy", I didn't fully understand. You mean the opposite of disorder, chaos or homogenization?
Thinking again what you suggested, there is a word that I would propose instead of entropy (not greek originated): Nirvana.
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| « Last Edit: Jul 6th, 2005, 3:41am by Ajax » |
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Re: Do you believe in the death of Universe?
« Reply #21 on: Jul 6th, 2005, 2:12pm » |
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on Jul 5th, 2005, 6:15pm, Icarus wrote:
Despite common perceptions, entropy is not the same as disorder. Maximal entropy states tend to be highly ordered.
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Entropy is disorder, but you need to define the term disorder properly. From what you post I think your definition of 'disorder' must differ from the standard (statistical physics) definition.
Disorder is well-defined in statistical physics. If people are interested I might try to write some of the line of thought here in this thread (not so easy, as quantum-physics concepts are inevitable), but maybe for now I can just post the resulting definition of the term disorder:
The disorder of a physical system in a certain macroscopically defined state is equal to (the expectation value of) the amount of information needed to describe the system fully in all its microscpic details.
Now the entropy is (up to a multiplyer that is dependent on units) just equal to the amount of disorder as defined above.
In other words: entropy is the information we lack about a system.
on Jul 5th, 2005, 6:15pm, Icarus wrote:
Maximal entropy states tend to be highly ordered.
[..]
Maximal entropy occurs when energy is distributed as evenly as possible. This is usually a very well ordered state.
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I think you are not considering the whole system (that is described in the multi-dimensional phase space), but limit yourself to some partial description (e.g. the 3D configuration space). Maximum entropy states are highly disorder in the phase space, but might seem ordered (uniform) in 3D space.
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Re: Do you believe in the death of Universe?
« Reply #22 on: Jul 6th, 2005, 2:29pm » |
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on Jul 5th, 2005, 6:15pm, Icarus wrote:
[..] they should have chosen the opposite sign, and defined a concept that is the opposite of entropy. [..] It would be something used up by processes as they occur, and its eventual loss (the zero-point of this quantity would be defined as the maximal entropy state) would be what brings the process to a stop. It would be easy to explain "Heat Death": Our universe was embued with a certain amount of this anti-entropy at its creation. When it is all gone, the universe will cease to "run". |
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So, what about replacing "anti-entropy" ("negentropy"?) by "available information"..?
By the way: "it" is never totally "gone". The only observables (from the outside) of a black hole is
its mass, its angular momentum, and its charge. Just five numbers. Five numbers is pretty close to zero considering the unimaginable amount of data needed to describe all the microscopic degrees of freedom of 'the inside' of a black hole that can take the size of up to billions of lightyears.
Close to zero, but not zero...
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Re: Do you believe in the death of Universe?
« Reply #23 on: Jul 6th, 2005, 6:39pm » |
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Jock - Sorry, but that bit about "disorder" is beside my point. Your statistical definition of "disorder" was originated exactly because of the tie-in between entropy and disorder already existed when statistical mechanics was developed. Unfortunately, this technical definition deviates from the normal non-technical meaning for the word.
A system in which every point is exactly identical in content has maximum entropy. There is no way for heat to flow or any process to take place without outside interference. However, to describe such a system as being "maximally disordered" is completely contrary to the normal, non-technical, meaning of the word. By the ordinary concept, there is no disorder in it at all.
All the technical definition of disorder does is shift where this disconnect is: from being between the concepts of entropy and disorder, to being between the technical and non-technical meanings of "disorder". This disconnect itself still exists.
As for the zero of what I will follow your lead in calling "negentropy" (but I don't care for that name), we are talking about slightly different concepts here: you are refering to the statistical definition, while I am thinking of the thermodynamic one. The main difference is, the statistical measure already has a predefined value zero, while the thermodynamic definition does not (the connection between the two is theoretical only, and can be modified).
By the work of Clausius and Caratheodory, the 2nd law of thermodynamics implies that the differential of heat transfer into a system, dQ, has an integrating factor. That is, there exist thermodynamic variables T and S such that dQ = -TdS. Further, this defines the variables T and S uniquely up to two constants. In particular, if there exist variables X, Y such that dQ = XdY, then there exist constants k, c such that X = kT and Y = (S-c)/k.
The variable T defines the temperature of the system, and is made unique by setting a value for some non-zero temperature (for the Kelvin scale, the triple-point of water is required to be at 273.16K). This also specifies S up to that additive constant c. S is then defined to be the entropy. Commonly in thermodynamics, S is left indeterminant, since it is only dS that is important in calculations.
What I am talking about is to make two changes to this scheme: Instead of the entropy S, I want to use the negentropy N = -S, so the defining equation is dQ = TdN. And second, I claim that there is a minimal value for N for any real system - a point below which no process can occur, but above which process still can. I would set this point as being the zero value of N.
The rule that entropy always increases in my system becomes "negentropy always decreases". That is, any non-reversable process uses up some of the negentropy of the system. When the system has used all of its negentropy, nothing more can occur in it without outside interaction. Such external interaction serves to imbue the system with additional negentropy, allowing internal processes to start up again.
Think about it: this is exactly the way how "energy" is thought to operate in the popular mind. Processes are describe as using up energy (though in fact energy is never used up - it is only transformed), and stopping when they are "out of energy" (though in fact just as much energy is there as at the start).
If we could come up with a catchier name than "negentropy" and push it, we could conceivably correct one of the most common misunderstandings of physics in modern society, and avoid some non-sensical concepts, and errors made by those who should know better but inadvertantly mix the popular and actual concepts of energy in their minds. (The thing that made me think of this in the first place was "zero-point energy". I kept seeing people who knew better state that if we can just tap into the infinite zero-point energy, we could have as much energy as we need. What they forget is that we already have as much energy as we need. What we need is negentropy, of which I see nothing to suggest is available in the zero-point energy.)
In statistical mechanics, it is customary to identify S as proportional to the log of Omega. Under my scheme, that identification becomes that N is proportional to a constant minus the log of Omega. The added constant is account for minimal possible information, and represents the difference between my zero and Jock's.
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| « Last Edit: Jul 6th, 2005, 6:44pm by Icarus » |
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Icarus
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Re: Do you believe in the death of Universe?
« Reply #24 on: Jul 6th, 2005, 7:05pm » |
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As for the suggestions of "available information" and "Nirvana" for negentropy:
There is a certain appeal, I must say, to the idea that we live and work by using up information, or burning up Nirvana. But I doubt that either would actually catch on.
But perhaps a word meaning "information" or "data" (other than "data") would be a good choice.
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"Pi goes on and on and on ...
And e is just as cursed.
I wonder: Which is larger
When their digits are reversed? " - Anonymous
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