Poll: Energy and Entropy.

[Laughing Man]

Sorry to put you on the spot, but I needed to say that I stated so because we do not have a measurement of the universe

Just because we do not have an accurate measurement is not the same as an infinite Universe and when it comes to Energy and Entropy you can't generalise by saying infinite for the sake of simplicity. IF the Universe is Infinite then entropy will never occur since the Universe is as big or as small as it is ever going to be and energy can neither be created or destroyed. Entropy in an infinite Universe can only occur if energy is able to be destroyed, but even then the word Entropy would be incorrect.

In essence your entire question can only be considered IF the premise of the Universe being infinite is accepted as fact and yes while we do not have an accurate measurement of it's size it is generally accepted that the Universe is not infinite.

 

[BarkBarker]

I recall watching something where they managed to gauge the shape of the universe up to the point(only like 4 or so years ago) and based on the shape of the known universe is speeding up in expansion or something with no sign of stopping at any particular point. Maybe space is an infinite after all?

 

[Zen Bard]

Quantum Snip

Thing is, none of this is relevant to your initial question, which (if I'm not mistaken) was "If Energy can neither be created nor destroyed, how can Entropy exist?"

Think of it this way; everything is made of the same stuff - atoms, protons, neutrinos, quarks, muons, leptons, etc. And all that stuff moves (vibrates/oscillates/spins) at different rates that we call "states", right?

All that stuff swirls around in a macrocosmic closed system that is our Universe. Sometimes collisions occur. These collisions can result in the formation of new particles or the annihilation of one or more of them. But they always result in a change in energy state. And it always goes to a lower state because energy is "lost" in the transition.

We get our "Heat Death" when the majority of stuff has transitioned to a low energy state. It's all still there. It's just useless .

Dark matter, dark energy all follow those same rules. Forces (gravitational or otherwise) only determine how all that "stuff" interacts in any given moment. And I'm not sure what you mean by a "Quantum Event". "Quanta" is just a term for packets of energy that have both wave and particle-like properties. While they bring their own set of intrinsic rules and challenges, there's nothing mystical or magical there.

Actually...Satinavian said it best:

The problem is that quantum thermodynamics and quantum field theory don't really change anything regarding this particular topic. They are only slightly more difficult to discuss (needing understanding of quantum interchangability, counting of states, uncertainty, entropy as information, entanglement and of course quantum decoherence).

Adding cosmology doesn't help too much either. Yes, inflation and so on makes counting of states difficult and we still don't really know what happened in the beginning, but thermodynamics is used in pretty much all cosmological models and yields the well known results.

Now if you'll excuse me, I'm off to yell at a cloud...

 

[renegade7]

But if energy just moves around, never disappearing, is there entropy?

Sort of, depending on how literally you take the mathematics. Energy is definitely a physical quantity, but entropy is closer a mathematical abstraction.

The real statement of the second law of thermodynamics isn't "Entropy always increases", it's "A closed thermodynamic system, regardless of its initial state, will ultimately end up in its most probable state."

Spoiler: Longer explanation

This is usually explained first in the context of a simple physical system called an Einstein solid. An Einstein solid is a system of quantum harmonic oscillators, that is, oscillators whose frequencies can only take on integer multiplies of a "ground state" frequencies, that is, if f[sub]0[/sub] is the ground state frequency, then the frequencies can only be things like 2f[sub]0[/sub], 3f[sub]0[/sub], and so on. This means that it only gain or lose energy in discrete amounts, or "quanta" such that if its ground state energy is E[sub]0[/sub] then it can only have energy 2E[sub]0[/sub], 3E[sub]0[/sub], and so on.

Now let's make the assumption that an Einstein solid is completely isolated from the outside world, and that it has N oscillators and q units of energy. Let's further assume that the state of an individual oscillator is not affected by the states of any of the other oscillators in the system, and that an individual unit of energy can appear in any individual oscillator with equal probability. So at any time, a unit of energy of energy in an oscillator can either remain there or move to any other oscillator, and all of these can happen with equal probability.

There is a simple way to represent the states of Einstein solid as a diagram. Let individual oscillators be represented by paranthesis and units of energy by asterisks. So the diagram (**)()(*) represents an Einstein solid with 3 oscillators and 3 total units of energy, with 2 units of energy in the first oscillator, 0 units in the second, and one in the third.

So now let's get into microstates and macrostates so we can get to probability. A microstate is a specific arrangement of units of energy in oscillators, and a macrostate is a set of equivalent states. So consider the Einstein solid with 3 units of energy and 3 oscillators. Then its microstates are

(**)(*)()
(**)()(*)
()(**)(*)
(*)(**)()
(*)()(**)
()(*)(**)
(***)()()
()(***)()
()()(***)
(*)(*)(*)

The set of states
(***)()()
()(***)()
()()(***)

are all said to be of the same "macrostate" because they all have one oscillator with three units of energy and two with zero. There are three states here, so it is said to have multiplicity three.

The "total multiplicity" of an Einstein solid with N oscillators and q units of energy refers to the total number of microstates it has. It is given by the function C(N,q) which is read "N choose q" and denotes the binomial coefficient [http://mathworld.wolfram.com/BinomialCoefficient.html]
. Note that this depends on the number of units of energy in the solid: if there are zero units of energy, then the solid has total multiplicity of one, there is only the state ()()(). But as we saw above, if there are three units of energy then the total multiplicity is 10. The probability that a system is in a given macrostate is the multiplicity of that macrostate divided by the total multiplicity of the system.

All right, now let's take two Einstein solids A and B and put them next to each other, assume that they each have three oscillators and that between them they have a total of six units of energy. Let M[sub]a[/sub be the multiplicity of a, same for b. Then look at the table:

q[sub]a[/sub]____M[sub]a[/sub]____q[sub]b[/sub]____M[sub]b[/sub]____M[sub]total[/sub] = M[sub]a[/sub]M[sub]b[/sub]
0 ____1 ____ 6 ____ 28 ____28
1 ____3 ____ 5 ____ 21 ____63
2 ____6 ____ 4 ____ 15 ____90
3 ____10 ____ 3 ____ 10 ____100
4 ____15 ____ 2 ____ 6 ____90
5 ____21 ____ 1 ___ 3 ____63
6 ____28 ____ 0 ____ 1 ____28

Apologies for the bad formatting, I don't know how to generate tables in markup. Anyway, the total multiplicity is the sum of all the M[sub]total[/sub], which is 462. Note that the state of highest multiplicity is the one where each oscillator has three units of energy.

What we can infer from this is that at any given time, all of these states are possible, but the state where energy has been distributed evenly between the two oscillators is more likely, with a probability of 100/462. If you were to make a graph with q[sub]a[/sub] on the horizontal axis and its probability on the vertical axis, this would be a normal distribution ("bell curve").

Now bear in mind that that is an extremely small system consisting of three atoms. Its normal distribution isn't very sharp, so it's actually not impossible that you'll see a state where the energy isn't distributed evenly. In the real world however, N and q[sub]a[/sub] would be on an order of magnitude closer to 10^23, and that distribution gets really sharp really quickly to the point where anything appreciably different than a perfectly even distribution of energy is all but impossible.

If you know anything about binomial coefficients or factorials, then you'll know that the multiplicity of a real-world system is going to be an incredibly large number, and this makes it difficult to work with. We can therefore make our lives easier by taking its natural logarithm (which has the effect of turning very large numbers into just large numbers), and for historical reasons we multiply the natural logarithm by k, which is Boltzman's constant. Thus we have S = k*ln(M) and we call this quantity the entropy of the system (we assume also that M is large enough that we can treat it like a continuous quantity). This also brings another advantage in that the natural logarithm is an elementary continuous function and therefore we can easily do all of the normal operations of calculus with it, whereas the continuous version of the continuous version of the binomial coefficient involves gamma functions [http://mathworld.wolfram.com/GammaFunction.html] which we'd like to avoid if at all possible.

Note that the natural log is monotonically increasing, so that as the multiplicity increases, so does the entropy.

Thus we arrive at the popular version of the second law of thermodynamics: "The entropy of a closed thermodynamic system will tend to increase over time."

This is all thanks to Daniel V Shroeder's introductory thermal physics textbook.

So yes, there is entropy. But you're kind of misreading what entropy actually is. Entropy is not a force that induces all physical processes to tend towards a given outcome, it's simply a quantity that we assign to the behavior of a system so that we can mathematically analyze it: when a system is in a given state, we say that it has an amount of entropy, and that state is going to change such that the increase in entropy is maximized. Entropy is a characteristic of the behavior of a class of physical systems operating comfortably within the classical regime (that is, not quantum or relativistic).

But more importantly, it's not clear that entropy is a relevant quantity when talking about fundamental cosmology, because it's not clear if the universe is a thermodynamically closed system. In the regime of classical physics, entropy increases. But when we're talking about either quantum field theory (at the fundamental level) or general relativity (at the global level of cosmology), entropy ceases to be well-defined.

The reason is that the second law of thermodynamics is derived from conservation of energy, and energy is not conserved in quantum or relativistic physics.

Given that the universe may be infinite, which is it that is true: That energy can be neither created nor destroyed, or that entropy will bring the total end of all that exists?

This isn't really a well-posed question. The second law of thermodynamics comes from the conservation of energy and is also how we infer that the universe would, barring other influences, end in heat death where all energy exists as inert mass or radiation. But like I said, we're not guaranteed conservation of energy . It is however a reasonable assumption that all that currently exists will inevitably be destroyed but the universe itself may still continue and if the universe does not end in a big crunch, big rip, or vacuum collapse then heat death will eventually reverse itself, although only after an enormous amount of time.

Big, Big Universe

Sorry to put you on the spot, but I needed to say that I stated so because we do not have a measurement of the universe, so we do not know where or if there are boundaries by any conceivable notion understandable to us.

OT: Discussion replies from me on subject will come later. Brain is tired.

About to get a lot more tired then: the big bang itself is the boundary of the universe.

If you boarded a rocket that would travel faster than the speed of light and left Earth in any direction then you would be also travelling backwards in time and, no matter which direction you went, would eventually reach the big bang.

 

[Glongpre]

The big bang is only a theory. There could be stuff going on within the universe which allows for the recycling of the spread out energy, but maybe it takes a real long time, or something.

The universe could be infinite. I find that a lot of theories seem to be stuck on the idea that everything must have a beginning, whether that be a God, or a Big Bang. And since it has a beginning, then it must have an end. I like it better to believe that there are cycles which keep the universe going, and that it has just always been.

 

[FalloutJack]

Sorry to put you on the spot, but I needed to say that I stated so because we do not have a measurement of the universe

Just because we do not have an accurate measurement is not the same as an infinite Universe and when it comes to Energy and Entropy you can't generalise by saying infinite for the sake of simplicity. IF the Universe is Infinite then entropy will never occur since the Universe is as big or as small as it is ever going to be and energy can neither be created or destroyed. Entropy in an infinite Universe can only occur if energy is able to be destroyed, but even then the word Entropy would be incorrect.

In essence your entire question can only be considered IF the premise of the Universe being infinite is accepted as fact and yes while we do not have an accurate measurement of it's size it is generally accepted that the Universe is not infinite.

Well, the problem with discussing this the other way is that we would then have to determine what's outside the universe, or if the term 'outside' means anything in reference to all matter and energy in said universe, as anything outside the stellar regions may be no border from here to there and still count as being part of said universe. Simplifying the massive complexity of existence, the likes of which we do not fully understand, isn't exactly a bad thing. We are engaging in the theoretical possibilities for our own amusement's sake. I just wanted to reduce the headaches likely to crop up.

>>>>>

That said, let's answer some spacey soul.

The mention of GN-z11 interests me. True, that due to its distance from planet Earth, anything that we see of it has already happened many years ago. Still very interesting. As Glongpre has said, there may be a constant recylcing/reforming that is going on that may always be going on. There may be no beginning and there may be no end. We don't know. We DO know that the universe is moving and spinning at incredible speed, though, its expansion from here to there going very fast. It's the sort of thing that invokes Carl Saigon and Animaniacs in one fell swoop.

I would like to thank those who did for clearing up a number of scientific notions that I did not have a perfect understanding of, Renegade especially. I will say, though, that while observing the universe far enough is like looking into the past, FTL travel could not possibly deliver you to the Big Bang. It's expending all the energy it can to arrive at a point in space shortly after the equivalent time you had lunch on Earth, instead of years later. To reach a time warp where you reach a place 600 light-years away so that our telescopes can spot us being there, 600 years into the past, you need a helluva lot more than that.

Back to the point. When I said 'all will be inevitably destroyed', I didn't mean in simply the herenow, but also the thenthere. All things, eventually unable to hold themselves together, for whatever reason. Sun fuel depleted, matter dissipated or eaten by black holes, black holes collapsed and gone. Nothing. To be considered void, or at least as empty as space would appear without features or activity in it. A complete lack of event, and nothing more. So, I asked myself if this was possible when there's energy, and I didn't know.

So, I asked you guys.

Seemed like something interesting to do. (Zen, leave those clouds alone, young man!) I wanted to hear what you thought, and what you're thinking is all very interesting to me, certainly a breath of fresh air. I know this is a rather heavy thing to put on a GAMING forum, but why the hell not? Still, with the inclusion of an actual textbook into discussion, we find that the examination of entropy in closed states is small-scale (because trying this in large-scale is harder and can take exponentially longer) and that a projection of situations via calculations can render a predictive model problematic.

Or, in short: THERE IS AS YET INSUFFICIENT DATA FOR A MEANINGFUL ANSWER.

That's a pain in the ass.

There is...one thing that I remember, though, speaking of small-scale, that makes me wonder about the universe re-assembling things, through gravity and pressure and whatnot. Maybe you recall a funny little story about some astronauts who brought coffee into space, against orders. They do that sometimes, sneak things aboard, even though it could potentially get into the instruments or in somebody's eye. Zero-G is unforgiving like that. The thing is, though, they had some simple coffee grounds hovering about, and - with no coaxing whatsoever - they began to form a system. They spun and orbited. It was a complete accident, seeing that happen.

Whenever and however the universe came to be, it did so by forming great bodies - the stars - with other bodies orbiting them. Their materials, and the order in which those materials were placed, came to them naturally in the process of creation. The binding forces of this universe cause parts of it to clump and spin together thus. Until we know why GN-z11 behaved the way it did, we can't really say this doesn't happen elsewhere. Some process made these things form and the forces pushing it so are still active. The universe is a very strange place.

So...other thoughts? Observations? Questions?

 

[wizzy555]

The fast creation of stars is not a problem for entropy and heat death provided the material of the stars are not being spontaneously created like the debunked steady state model (in which case conservation of energy is violated, the universe isn't a closed system and heat death can be perpetually delayed).

If GN-z11 is behaving unusually then it is more likely the astro-physics is wrong rather than thermodynamics.

BTW some corrections. Heat death is not everything a low energy state. Heat death is energy states perfectly mixed throughout the universe. Basically everything is the same temperature, this is likely to be a cold temperature but not necessarily and certainly warmer than the coldest places today.

Also if you are going to talk to real cosmologists I would avoid bold statements like "The universe is infinite" and "we cannot conceive of the boundaries of the universe". This is like going on an anime forum and saying "Well obviously the best anime is death note" and "who knows what is the best pantie shot".

 

[Zen Bard]

BTW some corrections. Heat death is not everything a low energy state. Heat death is energy states perfectly mixed throughout the universe. Basically everything is the same temperature, this is likely to be a cold temperature but not necessarily and certainly warmer than the coldest places today.

Fair point. Perhaps a more accurate statement would be "The heat death is when everything reaches a homogeneous energy state or state of thermodynamic equilibrium."

However a correction to your correction; "low energy state" is not the same as "cold temperature". Matter, for example, exists in a low energy state. Thermodynamically, "low energy" simply means it can no longer produce workable heat. If everything in the universe is reduced to a bunch of warm rocks, no workable heat can be produced without injecting some type of energy (photoelectric, kinetic or thermal) into the system.

 

[FalloutJack]

Also if you are going to talk to real cosmologists...

I...don't know any. Do you? Do any of 'em know the size of the universe? I know that they wouldn't really be antsy about the conversation, since I stated only that it 'might be', on the grounds that we dunno. I mean, it's only a conversation.

 

[Pyrian]

I will say, though, that while observing the universe far enough is like looking into the past, FTL travel could not possibly deliver you to the Big Bang. It's expending all the energy it can to arrive at a point in space shortly after the equivalent time you had lunch on Earth, instead of years later. To reach a time warp where you reach a place 600 light-years away so that our telescopes can spot us being there, 600 years into the past, you need a helluva lot more than that.

Let me try to explain why "tachyonic" FTL is effectively a form of time travel (there are other types of FTL which are not, e.g. wormholes). In relativity, going faster doesn't just mean arriving faster. From a stationary perspective, the near-FTL traveler ages more slowly, and that aging approaches zero as they approach light speed. A traveler at light speed does not age. From the travelers perspective, things are different; time seems to them to be normal, but distances are ever shorter. At light speed, there are no distances, and you arrive instantaneously upon departing (again, this is the traveler's perspective; from the stationary perspective, they're going at the speed of light).

Do you see where this is going yet?

By relativity, if you manage to exceed the speed of light somehow, you are now aging in reverse. Time is passing for you in reverse. You arrive before you leave, by your own reckoning. The universe continues in its grand direction, but the traveler is in the other lane.

A complete lack of event, and nothing more. So, I asked myself if this was possible when there's energy, and I didn't know.
...
Still, with the inclusion of an actual textbook into discussion, we find that the examination of entropy in closed states is small-scale (because trying this in large-scale is harder and can take exponentially longer) and that a projection of situations via calculations can render a predictive model problematic.

Or, in short: THERE IS AS YET INSUFFICIENT DATA FOR A MEANINGFUL ANSWER.

Insofar as the question is, "Does the existence of energy prevent heat death", then the answer is a resounding no - strictly speaking it's a requirement, after all. If the question is, "Will our universe inevitably result in an eternal heat death scenario of some sort", then the answer is "insufficient data" and quite possibly "required data is fundamentally impossible to collect".

Even in the details, there are suppositions about heat death that may not be true. Does Hawking's Radiation even exist? We can't measure it, and its formulation requires both relativity and quantum mechanics - systems that are not in agreement. Do protons decay? It's never been detected, and it's not even predicted in the Standard Model. If either form of matter is truly stable, then the potential energy tied up in those systems may endure asymptotically - never actually ending altogether.

 

[wizzy555]

Also if you are going to talk to real cosmologists...

I...don't know any. Do you?

I could go to their office.

Do any of 'em know the size of the universe? I know that they wouldn't really be antsy about the conversation, since I stated only that it 'might be', on the grounds that we dunno. I mean, it's only a conversation.

The observable universe is estimated to be 93 billion light years in diameter. There may be more but the light hasn't reached us yet and some may never be able to be visible.

 

[FalloutJack]

Snip

We're just sort of theorizing and discussing here for fun, taking what we know and what we can find out and seeing where it gets us to deal with the curiosity at hand. I think we may have taken it about as far as it can go, but you gotta admit it was a good run.

Light-based snip

For that many billion light years, the light has come in so we can see what went on. Any reason it wouldn't reach us further? Too much stuff in the way? I'm curious.

FTL Snip

Lemme break this up into two.

{1} No no, I got that. It IS time displacement in that you didn't arrive 600 light-years away, 600 years later, but the space of perhaps only a few minutes, traveler perspective. I'm not sure the same engine can be used to reach the 600 light-years away, also 600 years in the past, because by the time we saw that point in space, 600 years had passed to allow us to see it, so that it's moved on by an additional 600 years by then, thus to time-warp to the point you may be talking about, you need alot more effort, because you'd be circumventing a 1,200 year reality.

{2} At the time, I was referring more to insufficient means to grasp the fullness of entropy's effect on the massive scale, but I understand your meaning.

 

[Terminal Blue]

As far as we know, energy can be created (or at least, energy can enter our universe seemingly from nowhere). We can tell because the expansion of the universe seems to be accelerating, which shouldn't be possible.

The current most likely scenario for the end of the universe is actually that there will be so much energy in the universe that planets, then atoms, then finally the universe itself will be ripped.

Without dark energy, then eventually all energy in the universe would become evenly distributed and molecular motion would stop. The universe in this sense would not have a concrete end, it would just become completely still and nothing would ever happen within it. The energy would not be gone, the universe would have the same energy it always had, it would just be so spread out that it would have no impact on the universe whatsoever.

 

[Pyrian]

No no, I got that.

You sure? ;D

It IS time displacement in that you didn't arrive 600 light-years away, 600 years later, but the space of perhaps only a few minutes, traveler perspective.

Believe it or not, that's just standard STL relativity. No FTL required.

I'm not sure the same engine can be used to reach the 600 light-years away, also 600 years in the past, because by the time we saw that point in space, 600 years had passed to allow us to see it, so that it's moved on by an additional 600 years by then, thus to time-warp to the point you may be talking about, you need alot more effort, because you'd be circumventing a 1,200 year reality.

Hmm? That's just a matter of scale. The trick is direction, and it gets really weird, so bear with me. In the stationary frame, the ship moved 600 light years in, say, 300 years. In the ship's frame, though, it arrived 300 years before it left. That's difficult to conceptualize, but basically you could pick up a passenger at the arrival point and have them step off at the departure point.

And you don't actually have to GO anywhere - you could just make a circle. So, you launch a ship that returns to your station 100 years later, but instead of embarking when it's leaving and disembarking when it arrives, you embark at the end of the journey and step off at the beginning - 100 years earlier.

That's a straight-up time machine.

(Mind you, the logistics of how you embark, disembark, and accelerate are all essentially unsolvable and riddled with the usual paradoxes, I'm just trying to explain how it's conceivable and why people talk about it.)

 

[FalloutJack]

Snip

Hold on, I think we got something confused here. STL would be taking 600 years to cover 600 light-years. It's moving at the speed of light, a light-year (roughly) for every year. I am talking about FTL reducing that to a few minutes, and saying you wouldn't arrive in our telescope vision that day because what they would be looking at is already an additional 600 years past. By the time we see it on Earth, it's already long gone, requiring a much larger circumvention in time.

If you leave there to go find the spot we're looking at that's 600 light-years away at twice the speed of light (if that's what you're going for, say), you get there in half the time, you're reaching it 300 years sooner than the light from our sun did, but you're not on our telescope the day you left, because you didn't go to the time where the area was when we looked. You went to its future, 300 years later.

If you opened up a wormhole to cover 600 light-years instantly, you still wouldn't be on the telescope for another 600 years, because you went to present-day 600-year-away space, and the light will take that long to reach us to see it, meaning that you would miss the past because it was still our present, while our telescopes are looking at the past. Light acceleration has allowed for some weird effects and I would believe you could use FTL to travel to yesterday, no problem, but I think you need even more acceleration for a true timewarp.

I'll give you an example. Same distance, similar problem, but taken like this. We are on different planets, 600 light-years away. Breakfast time on our world is at the same time and you decide to join me for lunch. No worries. You just crank up your superluminal drive and zip on in. But then, you say, "I think I'll go back to Woodstock. I'll just travel in a circle according to precise calculation and get here on Earth before I left.". Before I can say anything, you head off to your ship.

The calculation is fed into the navigational system and you head off, but when your circle is complete, you don't find the Earth. Why?


Your drive is designed to get you there now. Theoretically, it's circumventing time, but it's like traveling to Australia from America. As much as we like Superman (I'm assuming), he can't go to Woodstock by turning back the Earth, and you can't use your FTL drive to get back to the swingin' sixties. Your drive is taking you to where the Earth was in the universe, but consider acceleration, for a moment. As with any vehicle, it can move best in a straight line. Compensating for drift and obsctacles along the way, anywhere you're planning on going is definitely that. Turn too much at once, and either your acceleration goes or your ship does.

This is, at least, what it seems like at the moment. Some physical law is getting in the way.

Snip

I think the idea that we're here to figure it all out is a very nice to be. I just figured we were out of good hypotheses, at he moment, for this. If I'm wrong, no worries, but still I like that idea, and I don't wanna spitball low-blows or something here. This is for pleasure.

Snip

I hadn't heard anyone say that dark energy is producing energy, that I know of. I have heard that people seem to think that some energetic quality of its own IS the reason for acceleration, like a motive force. But then again, most people aren't sure WHAT dark energy really does. Again, much-theorized stuff.

 

[Terminal Blue]

I hadn't heard anyone say that dark energy is producing energy, that I know of.

Nah, the dark energy is energy.. the point is that if we assume that some type of energy is causing the increase in universal expansion then that energy must be constantly increasing somehow in order for the rate of expansion to keep increasing. We have no real explanation as to how because this energy seems to be otherwise invisible and seems to have no interaction with anything in our universe except gravity.

Whether the energy is being created or whether it's leaking into our universe from outside or exactly what is happening we just don't know.

 

[wizzy555]

For that many billion light years, the light has come in so we can see what went on. Any reason it wouldn't reach us further? Too much stuff in the way? I'm curious.

If the expanding universe thing is correct then the outer edges are expanding faster. If it is expanding faster than the speed of light then the light will never reach us because the space it is travelling is growing faster than it can travel. Imagine an ant on a balloon, the ant wants to find another ant on the balloon but the balloon is expanding faster than the ant can walk. The ant is doomed to an eternity on its own. Christ I dunno which is more horrifying, that or heat-death.

 

[FalloutJack]

I hadn't heard anyone say that dark energy is producing energy, that I know of.

Nah, the dark energy is energy.. the point is that if we assume that some type of energy is causing the increase in universal expansion then that energy must be constantly increasing somehow in order for the rate of expansion to keep increasing. We have no real explanation as to how because this energy seems to be otherwise invisible and seems to have no interaction with anything in our universe except gravity.

Whether the energy is being created or whether it's leaking into our universe from outside or exactly what is happening we just don't know.

*Thinks on that*

Theory: Perhaps gravity is the point. Dark matter is dense and therefore has a kind of pull because of its weight. Perhaps dark energy is to gravity what photons are to light, thus gravitational force throwing things around.

For that many billion light years, the light has come in so we can see what went on. Any reason it wouldn't reach us further? Too much stuff in the way? I'm curious.

If the expanding universe thing is correct then the outer edges are expanding faster. If it is expanding faster than the speed of light then the light will never reach us because the space it is travelling is growing faster than it can travel. Imagine an ant on a balloon, the ant wants to find another ant on the balloon but the balloon is expanding faster than the ant can walk. The ant is doomed to an eternity on its own. Christ I dunno which is more horrifying, that or heat-death.

An interesting - if worrying - thought, though the light itself seems to break its own record by not being a constant, but in acceleration itself. Another thought is that our field of vision in the universe can't see more because once our limit has been reached, other things are so far away that they're effectively miniscule and therefore nigh-invisible. This has apparently been a problem of the past when earlier scientists were examining space and not seeing it all. (I actually found a documentary that's talking about why space is space, funnily enough.)