Large Hardon Collider

[Max™]

Entropy tends to a maximum.

Ordered states have low entropy.

Heat is more ordered than a cool and uniform state.


The Universe has a finite amount of energy and matter, and seems to have a finite amount of order.

As time tends towards infinity, entropy does as well, so order tends towards zero.

Eventually there is no meaningful way left to measure change, no usable energy anywhere, everything is flat and cold.


Not even the stars will last forever.

[Khamsin]

Why are you worried about it? Not even your descendants will be around when that happens.

But his descendant's descendants may be around. Provided his family line makes with the procreatin'.

[Apol]

Thanks for that, Max!

Complete nothingness is a very interesting and petrifying thing to think about. It's what I always bring up when people are talking about 'getting bored' on the subject of living forever. People say I'm no fun

[Max™]

Np, figured the specific details behind the laws of thermodynamics wouldn't make as much sense as simply explaining what it means.

Universe started in a very ordered, energetic, highly symmetrical state, it is trending towards a low energy or zero energy, asymmetric, state of disorder.

[Woozie]

I keep track of the developments of information technology and the study of the human brain.

It should be possible within the next 100 years to transfer a human awareness into a machine.

It should be possible before then to turn off the self-destruct devices embedded in our cells.


There's a reason I avoid risking my health drastically, I need to last long enough to upgrade from this body.

I don't know much about biology, but wouldn't turning off the self-destruct mechanisms in our cells do much more harm than good?

Any chance one of you guys could explain heat death in layman's terms?

After poking around the Wiki page, I felt more confused than when I first started~

tl;dr incomming:

Spoiler: show

In order to understand heat death, you need to know a bit about entropy.

If you look up entropy, you'll often see the definition "The total disorder of a system". This is kinda true.

A better way to understand entropy is to understand macrostates and microstates. Imagine if you had 100 coins. Two questions you could ask about your system of coins are "how many total coins are in the state 'heads', and what state are the individual coins in?". So the answer to your first question may be "There are 48 heads (and 52 tails)", and the answer to your second question may be "The first coin is a heads, the second is a heads, the third is a tails" etc.

The state of the individual coins is the "microstate". The state of the entire system is the microstate. So our macrostate is "48 heads". I'm obviously not going to list all 100 microstates lol.

Note that every microstate has the exact same probability. The 1st coin has a 50% chance of moving to heads after the next toss, and 50% chance of tails in the next toss (in general, systems wont always have the exact same chance of every state. This example just happens to).

Now let's see how many different microstates are available to this system. There are 2 choices 100 times, so the rules of probability would state that there are 2^100 states, each of which has the probability 1/2^100.

Let's look at an individual microstate. Consider the state where every single coin is on heads. There's only one way to arrange the coins so that each coin is on heads (I'm assuming the coins are labeled so you can't switch coin 1 and coin 2 and say "Tada! I have a new state").

Now consider the state "Every coin is on heads except coin number 50". There's exactly one way to do this, and that's to have every coin but 50 on heads, and 50 be on tails.

Now consider the state "Every coin is on heads except coin number 70". Again, there's exactly one way to do this. Every coin but 70 will be on heads, and 70 will be on tails.

But let's look at the macrostate of these two examples. The microstate of the first example "Every coin is on heads except coin number 50" has the macrostate "99 heads". The microstate corresponding to the second example "Every coin is on heads except coin 70" has the macrostate "99 heads", which is exactly the same as the first example. As a matter of fact, there are 100 ways to arrange the coins so that 99 are on heads (i.e. exactly one is on tails. You can make the first coin tails, or the second, or the third...etc).

So there's 1 microstate state corresponding to the macrostate "100 heads". But, as we've just shown, there are 100 microstates corresponding tot he macrostate "99 heads". So there are 100 times more states corresponding to "99 heads" than "100 heads". So if you randomly toss 100 coins, you are 100 times more likely to get "99 heads" than "100 heads".

Now consider the macrostate corresponding to "98 heads". If my math is right, there are 9900 ways to arrange 100 coins this way. So you are 9900 times more likely to get 98 heads than 100 heads, and 99 times more likely to get "98 heads" than "99 heads". As you can see, the more heads you add, the higher the probabilities become. Once you hit 50, you reach your maximum (3.068518756254967*10^93, which is 3 billion trillion trillion trillion trillion trillion trillion trillion times more likely than 100 heads. a 3 with 90 zeroes following). Once you reach less than 50 heads, the probabilities go back down (because, for example, 1 head is the same thing as 99 heads because 1 heads means 99 tails).

Most people would consider 100 coins on heads is an "organized set". The same would be true of "100 tails". It's an orderly way to arrange your coins. As you can see, the orderly ways to arrange things are MUCH less likely than the disorganized states.

Entropy is a number that measures how the amount of microstates corresponding to to a given macrostate. As you've seen, a macrostate with more corresponding microstates is much more likely. Typically, the disorganized states are WAY more likely.

Think about how easily your room gets messy. There are only a few arrangements of your room that correspond to the macrostate "clean". There's a limited ways to set up your room so that it's a clean room. But there are tons of ways a room can be messy. So it's easier to get your room messy than to get it clean. That's why your room gets messy easily without you even trying, but you usually have to work specifically to get it clean.

So what does this have to do with science or heat death? In physics, the macrostates correspond to quantities such as pressure, volume, and temperature. The whole purpose of the example above was to show you how much more likely high entropy states are than low entropy states. Even with just 100 coins, the highest entropy state was waaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa aaaaaaay more likely than the lowest entropy state.

Suppose you put the coins on a table that shakes in a way that causes the coin to flip. Put the coins in any state you like. Put them in the all heads state if you want. No matter how you put it, each flip is MUCH more likely to push the coins into a higher entropy state (i.e. a state with closer to 50 coins) than they are to be pushed into a low entropy states. And this is with just 100 coins. If there were a thousand coins the probabilties of high entropy states gets WAAAAAY higher. Unfathomably higher. Now consider the fact that macroscopic systems typically consist of MUCH more particles. One mole of a substance is on the order fo 10^23. So imagine how much more probable the high entropy states are here, in just one mole. The probabilities are so incredibly extreme that we make a law out of it. It's the second law of thermodynamics, and it states that the entropy of a system will always decrease. As you can see, there is a chance that the system could go into a lower entropy state, the the probability is so incredibly ridiculously unfathomably low that you can rest assured that we'll never see it happen in this universe (well I guess given an infinite amount of time it would eventually happen, but it would take an extraordinary amount of time).

Sorry for the huge explanation, but if you're wandering around the wiki pages and such, you need some sort of idea about entropy in order to understand heat death.

So we can rest assured that every system in this universe is always evolving towards a high entropy state. But why is entropy important? What does it do?

Well, there is a maximum amount of entropy in any system. So what happens if the universe reaches its maximum entropy? Since every process increases entropy, and entropy is at its max, then no processes can take place. Nothing can be done in a universe with max entropy. No stars will burn, no chemical reactions, no nothing. The universe is essentially dead. Also note that entropy is related to temperature. Notice how we have really hot suns living in a really cold vacuum? Well, in a max entropy, the temperature of everything evens out. Every part of the universe will be the same temperature. There will be no variations from place to place. No hot suns in the middle of a cold vacuum (like I said, stars can't exist at this point anyways). Every part of the universe will be the same temperature (and that temperature will be very close to absolute zero. Heat death is actually very cold. We call it "heat" death because of how heat is closely associated with entropy).

Everything we do in our lives depend on entropy. The efficiency of power plants depend on entropy. Power plants work by taking advantage of lower entropy systems. Our bodies can extract energy from food and use it because of the lower entropy of foods. Every energy source is derived from lower entropy things. So even if we were androids who didn't need stars or planets or food, we still couldn't survive heat death because there would be no way to have a power source. There's no way to extract energy from a higher max entropy system.

Like I said, high entropy states are so much more probable that heat death is inevitable if the universe survives long enough. There's no avoiding it. The universe will certainly keep going towards that state until it reaches it.

[Woozie]

Entropy tends to a maximum.

Ordered states have low entropy.

Heat is more ordered than a cool and uniform state.


The Universe has a finite amount of energy and matter, and seems to have a finite amount of order.

As time tends towards infinity, entropy does as well, so order tends towards zero.

Eventually there is no meaningful way left to measure change, no usable energy anywhere, everything is flat and cold.


Not even the stars will last forever.

I understand what you're saying, but he may misinterpret your post and think entropy goes to infinity. It goes to it's maximum, (which is so high that we may as well call it infinity, but technically it's still a finite number. If entropy could go to infinity, I don't think there would even be a heat death).

Edit: I just realized how overboard I went in my explanation. I'm just making sure I tell Apol enough so that if he looks it up online he can understand what they're saying.

[Apol]

Wow... thanks very much for taking the time to explain it in such detail, Woozie. I appreciate it.

It makes alot more sense when you put it all like that. Not to the point of being able to repeat it to someone else, but enough for me to think about heat death and better understand the 'why'.

How do you guys think the universe will come to its end? Contracting or heat death or anything else? From what Woozie says I guess heat death seems the most probable, but I'm curious if anyone else thinks that another method will beat it to the punch.

[Eliseos]

From what we know of the current mass of the universe, it will keep expanding forever, thus having heat death occur at some point in the future. If we find some hidden mass out there (I don't think it's very likely), it would have to be a considerable amount to get to something like a "big crunch".

[Kaylia]

I don't know much about biology, but wouldn't turning off the self-destruct mechanisms in our cells do much more harm than good?

He was talking about telomerase? Wouldnt you turn into a huge cancer if you removed that from your cells? lol

I would like to hear a biologist on this, but I'm also willing to bet it's not something you can remove or replace easily

[Stilzkin]

I keep track of the developments of information technology and the study of the human brain.

It should be possible within the next 100 years to transfer a human awareness into a machine.

It should be possible before then to turn off the self-destruct devices embedded in our cells.


There's a reason I avoid risking my health drastically, I need to last long enough to upgrade from this body.

Would you still be you if you were a machine?
I'd imagine a human to machine transfer would end up with some "losses" like your emotions wouldn't work the same and stuff. A machine even with all my memories wouldn't be me unless it worked exactly the same as I do as it would take different actions than I would have. A machine me would be more like a "next level son", taking more of me then just my genes but not really me.

[Woozie]

Wow... thanks very much for taking the time to explain it in such detail, Woozie. I appreciate it.

It makes alot more sense when you put it all like that. Not to the point of being able to repeat it to someone else, but enough for me to think about heat death and better understand the 'why'.

How do you guys think the universe will come to its end? Contracting or heat death or anything else? From what Woozie says I guess heat death seems the most probable, but I'm curious if anyone else thinks that another method will beat it to the punch.

Well, as Eliseos said, there's not enough mass for the big crunch to occur. So the only things we should be concerned about are Heat Death and The Big Rip. The Big Rip is a scenario that will only occur if dark energy satisfy certain criteria.

What happens in this scenario is that dark energy causes the expansion of the universe to keep accelerating. There's no reason the universe itself can't expand faster than light. However, nothing *in* the universe can travel faster than light. So this means gravity and electric forces don't travel faster than light.

So what happens when the universe starts to expand faster than light? Well, first of all, note that rate at which the universe is expanding is relative. Distant galaxies are expanding faster the not-so-distant galaxies. The closer two objects are, the less the expansion of space between the two objects.

So if the universe starts expanding too fast, eventually the light from distant galaxies could never reach us (because the space between us and the distant galaxies is expanding faster than light itself). The gravitational effects of these galaxies also travels at light speed. So we would no longer experience gravity from distant galaxies. However, the gravity we experience from distant galaxies is negligible anyways, so we wouldn't notice anything different. We'd just notice that our powerful telescopes suddenly can't see anything beyond a certain point anymore. It would look like everything beyond a certain point just vanished.

Eventually, the expansion would be so fast that galaxy clusters can't hold themselves together anymore. Like I said, the gravity only travels light speed, so once the distance between two galaxies is expanding faster than light, these two galaxies can no longer affect each other gravitationally (in fact that have no influence on each other at all whatsoever since all effects are either light speed or slower. So the two galaxies would be permanently cut off from each other. Galaxy clusters are "ripped" apart).

As the expansion continues, eventually our own galaxy would not be able to hold itself together, for similar reasons. Then solar systems would no longer be able to hold themselves together (again, same reasons. Gravity from the stars would never reach other stars or planets). So galaxies and then solar systems are "ripped" apart.

At this point, the sun would disappear from our sky because light from the sun can no longer reach Earth. And since gravity from the sun can't reach Earth anymore, the Earth would be unbound from it's orbit (but we'd die way too fast to see the effects, as I'm about to explain).

After this point, the expansion of the universe would get so fast that planets can't hold themselves together. Remember, electromagnetic attraction travels at the speed of light as well. So eventually even atoms couldn't even hold themselves together. The distance between electrons and protons would be expanding faster than light, so atoms are ripped apart too at this point.

Then, the nucleus of atoms are ripped apart. Then I guess protons and neutrons would be ripped apart though I'm not too sure about this last point. I'm so used to quark confinement that I just can't imagine in my own mind the idea of quark structures being ripped apart lol. But gluons (the "messenger" for strong nuclear force) travel way slower than light, so I guess it would have to happen, idk.

As you can see, eventually every particle in the universe is completely isolated in every way from every other particle in the universe.

From the way I understand it, after we see the stars in the night sky go black, we only have 20 minutes left to live. It happens that fast. So we wouldn't have to worry about freezing to death when we're cut off from the sun. We'd be ripped to shreds very soon after.

Other than heat death, there's also a possibility that our universe's current state isn't actually stable. If you want to learn more about that, go up near the top of this page and click on "search this thread". Type in "metastable" and you'll see what we talked about earlier. This scenario is the only one that's not way into the future. We could all be suddenly destroyed at any moment if this is correct.

Also:

View Past Public Lectures - Perimeter Institute for Theoretical Physics

Very good site for physics lectures. It's all at a level where any person could understand.

Also:

Ultimate fate of the universe - Wikipedia, the free encyclopedia

[Kaylia]

From the way I understand it, after we see the stars in the night sky go black, we only have 20 minutes left to live. It happens that fast. So we wouldn't have to worry about freezing to death when we're cut off from the sun. We'd be ripped to shreds very soon after

I wish I would be around to see that. It must be amazing to see the end of the world with your own eyes.

[Kilhart]

The idea of heat death kind of sucks to think about. D:

[Kaylia]

The idea of heat death kind of sucks to think about. D:

Not really, we will (as a race) be dead long time before it.

[Eliseos]

I wish I would be around to see that. It must be amazing to see the end of the world with your own eyes.

Yeah, I can't imagine gazing up at the sky and seeing stars disappear like that. Add that to the list of all the cool shit I'll never be able to see.

[Kilhart]

Not really, we will (as a race) be dead long time before it.

Well, I mean the idea that even if the human race is somehow able to conquer all other things threatening its survival, we'd still be fucked in the end and nothing anyone has ever done will ever matter. Depressing thought.

[Shiroikage]

He was talking about telomerase? Wouldnt you turn into a huge cancer if you removed that from your cells? lol

I would like to hear a biologist on this, but I'm also willing to bet it's not something you can remove or replace easily

Yeah, adding telomerase activity to cells probably is not a good thing in and of itself without any other changes. We just don't have data for it in whole human models, so obviously no real conclusions can be made. Basically, eukaryotic chromosomes have telomeres at the end of their chromosomes which shorten each time they divide. (there are some very interesting exceptions to the telomeres only at the end, and these work very well against creationist arguments). After about 50 cell divisions, normal animal cells (read: not stem cells) have telomeres that have been so shortened that they cannot divide anymore and become senescent.

Naturally, if you immortalize a cell for whatever reason, it's already got one of the characteristics of a cancerous cell. This isn't necessarily a problem, but it's probably going to require less mutations to actually make the cell into a cancer cell.

I'm assuming that he's talking about apoptotic (programmed cell death) mechanisms if he's talking about self-destruct mechanisms, though, and, outside of defects, those are generally only induced in cases where cells actually should be being killed.

Dealing with aging is a complicated topic, and there's no single answer to the problem.

[Eliseos]

Well, I mean the idea that even if the human race is somehow able to conquer all other things threatening its survival, we'd still be fucked in the end and nothing anyone has ever done will ever matter. Depressing thought.

Cheer up, we'll never last that long.

[Woozie]

I don't know what would be cooler (or scarier), it being night time during the big rip and seeing all the stars blink off one by one until eventually the moon blinks off, or it being daytime and suddenly seeing the sun just vanish.

[Kaylia]

Yeah, adding telomerase activity to cells probably is not a good thing in and of itself without any other changes. We just don't have data for it in whole human models, so obviously no real conclusions can be made. Basically, eukaryotic chromosomes have telomeres at the end of their chromosomes which shorten each time they divide. (there are some very interesting exceptions to the telomeres only at the end, and these work very well against creationist arguments). After about 50 cell divisions, normal animal cells (read: not stem cells) have telomeres that have been so shortened that they cannot divide anymore and become senescent.

Naturally, if you immortalize a cell for whatever reason, it's already got one of the characteristics of a cancerous cell. This isn't necessarily a problem, but it's probably going to require less mutations to actually make the cell into a cancer cell.

I'm assuming that he's talking about apoptotic (programmed cell death) mechanisms if he's talking about self-destruct mechanisms, though, and, outside of defects, those are generally only induced in cases where cells actually should be being killed.

Dealing with aging is a complicated topic, and there's no single answer to the problem.

I don't know enough to reply anything worthwhile, but thanks for the info.


I'm just going to trust nature and evolution on this. I mean, cells are one of the most efficient machine in the universe, and are incredibly better than anything we made with sciences. I have hard time to think we could improve them a lot more, but we will see.

I don't know what would be cooler (or scarier), it being night time during the big rip and seeing all the stars blink off one by one until eventually the moon blinks off, or it being daytime and suddenly seeing the sun just vanish.

Seeing a giant robot tosses galaxy at another giant robot, but that's another topic.

Wouldn't they red shift instead of blinking? Or it's too fast and we wouldn't notice it.