We need to change our theories about the end of the universe

[HoloYolo]

1. The cold death

This theory states that star-making gas and dust will be used as even our neighbors drift away as the universe expands. The only things remaining after trillions of years are neutron stars and black holes, with the addition of black dwarves.

Hold up, why would gas disappear? Every time a supernova occurs, the gas from the red supergiant gets flung out, but wouldn't that be enough gas to recycle the gas and make a new star? Same with regular red giants, the planetary nebula should have enough gas for another star.

2. The heat death

This theory states the universe will slow down and reverse in expansion, causing it to contract and heat up. But how would it slow down? The universe expanded at birth, and should continue to, unless dark matter has apparently stopped the universe, for some odd reason. Newton's laws of motion wouldn't allow this, as it states that the universe retreating would have a force going forward at the same speed, stopping the universe in it's place.

3. Ripped apart

This theory states the universe will speed up in it's expansion, causing atoms to be ripped apart, never to clump into matter again. But who's to say, if the universe ends this way, how do we know 2 atoms are going in a intersecting direction? The atoms will impact, causing them to clump, and have a gravitational pull 2x compared to the other atoms. The atoms will clump, start forming matter, and sorta reform the universe after billions to trillions of years. This causes new universes, maybe where we came from.

I'll debate in a mature matter if I screwed something up. I'm not a physician, just a student debating the end of universes.

[ZetaX]

@1.: You lose usable mass (read: elements lighter than iron) each time. At some point there will not be enough left.

@2.: You misunderstood the theory completely here. This has nothing to do with Newron's laws. But if you want, just imagine gravity pulling everything together again (that's only half the truth, but still works).

@3.: They cannot clump. The expansion between two atoms will at some point be faster than the speed of light and from that point on there can be no forces or other interactions between them.

[HoloYolo]

[QUOTE=ZetaX;1808736]@1.: You lose usable mass (read: elements lighter than iron) each time. At some point there will not be enough left.

@2.: You misunderstood the theory completely here. This has nothing to do with Newron's laws. But if you want, just imagine gravity pulling everything together again (that's only half the truth, but still works).

@3.: They cannot clump. The expansion between two atoms will at some point be faster than the speed of light and from that point on there can be no forces or other interactions between them.[/QUOTE]

@1:Forgot the stars end their lives with fusing Iron, but the hydrogen and helium left because the hydrogen and helium weren't at the core still can form a star.

@2: Newton's laws state that a force will have an equally opposing force, meaning that the universe will stop in place because 2 forces are going in opposite directions at an equal speed.

@3: Gravity is a force that pulls on anything at any speed. The Space Shuttle moves at 17,000 miles an hour in orbit, but the gravity from the Earth still pulls on it. I could fly by Earth at the speed of light and for a brief moment experience it's gravity.

[Ethanadams]

Um what about the universe collapsing on itself recreating the Big Bang

[ZetaX]

@1:Forgot the stars end their lives with fusing Iron, but the hydrogen and helium left because the hydrogen and helium weren't at the core still can form a star.

Ones? Sure. Twice? Sometimes. Ten times? Nah. It simply ends somewhere. A star must have a vertain mass to even achieve fusion.

@2: Newton's laws state that a force will have an equally opposing force, meaning that the universe will stop in place because 2 forces are going in opposite directions at an equal speed.

The universe itself is not moving. It is expanding. Newton simply does not apply. You can still apply it to two galaxies far apart: they then will attract each other and thus, by Newton, both move towards each other.

@3: Gravity is a force that pulls on anything at any speed. The Space Shuttle moves at 17,000 miles an hour in orbit, but the gravity from the Earth still pulls on it. I could fly by Earth at the speed of light and for a brief moment experience it's gravity.

Gravitational force moves at the speed of light. Anything that moves away faster than that won't be reached by it. Same for electromagnetism (or any other force, but the others are totally irrelevant).

Your example has speeds smaller than c and things not even moving away.

[HoloYolo]

Um what about the universe collapsing on itself recreating the Big Bang

That is the simplified version of the heat death.

[xXIndestructibleEVAXx]

The Big Freeze (cold death) is what's most likely going to happen. The heat death (which is the official name for the Big Freeze, as you have the names wrong) isn't going to happen without ADDING more matter to the universe, which breaks the laws of thermodynamics, and the Big Rip is the second most plausible/likely one, but the Big Freeze will probably happen WAY before the universe can accelerate that fast.

[Kryten]

That's not what 'heat death of the universe' means.

[HoloYolo]

Ones? Sure. Twice? Sometimes. Ten times? Nah. It simply ends somewhere. A star must have a vertain mass to even achieve fusion.

The universe itself is not moving. It is expanding. Newton simply does not apply. You can still apply it to two galaxies far apart: they then will attract each other and thus, by Newton, both move towards each other.

Gravitational force moves at the speed of light. Anything that moves away faster than that won't be reached by it. Same for electromagnetism (or any other force, but the others are totally irrelevant).

Your example has speeds smaller than c and things not even moving away.

I see, I realize my mistakes. But that's what science is. Questioning anything we know to find a different answer. I guess my argument was wrong. It happens. I will be back again with more, you shall see.

[xXIndestructibleEVAXx]

It's alright, and you are right. Science is about making mistakes and learning form them.

[HoloYolo]

That's not what 'heat death of the universe' means.

Yes it does, my I recommend research and an article proving me otherwise?

[xXIndestructibleEVAXx]

http://en.wikipedia.org/wiki/Heat_death_of_the_universe

"The heat death of the Universe is a historically suggested ultimate fate of the universe in which the Universe has diminished to a state of no thermodynamic free energy and therefore can no longer sustain processes that consume energy (including computation and life). Heat death does not imply any particular absolute temperature; it only requires that temperature differences or other processes may no longer be exploited to performwork."

[Bill Phil]

So, the heat death of the universe is basically an entropy-death?

[Ethanadams]

So what will happen to a person during the end of the universe I would pay to see that ÃŽâ€

[BlueCosmology]

1. The cold death

This theory states that star-making gas and dust will be used as even our neighbors drift away as the universe expands. The only things remaining after trillions of years are neutron stars and black holes, with the addition of black dwarves.

That isn't "the cold death" (there's no accepted cosmological term called that anyway, but I assume you meant the Big Freeze, also known as heat death) that's an intermediate step on the way to the end of the universe, for instance the big rip which you say in your third point.

Hold up, why would gas disappear? Every time a supernova occurs, the gas from the red supergiant gets flung out, but wouldn't that be enough gas to recycle the gas and make a new star? Same with regular red giants, the planetary nebula should have enough gas for another star.

Conservation of energy. Hydrogen fuses to form helium and helium fuses and so on, releasing energy. Takes the same amount go go the other way around, every star uses up a lot of light elements that are needed to form a star.

2. The heat death

This theory states the universe will slow down and reverse in expansion, causing it to contract and heat up.

But how would it slow down? The universe expanded at birth, and should continuehttp://cdncache-a.akamaihd.net/items/it/img/arrow-10x10.png to, unless dark matter has apparently stopped the universe, for some odd reasonhttp://cdncache-a.akamaihd.net/items/it/img/arrow-10x10.png. Newton's laws of motion wouldn't allow this, as it states that the universe retreating would have a force going forward at the same speed, stopping the universe in it's place.

Newton's laws do not apply in the slightest when talking about cosmology, however even if they did Newton's laws say nothing remotely similar to that. I assume by "states that the universe retreating would have a force going forward at the same speed" you mean every action has an equal and opposite reaction (a force does not go at a speed). This does not in any way at all prevent things expanding from collapsing. One object would pull another object towards itself and vice versa via gravity, causing them both to be attracted to their center point.

3. Ripped apart

This theory states the universe will speed up in it's expansion, causing atoms to be ripped apart, never to clump into matter again. But who's to say, if the universe ends this way, how do we know 2 atoms are going in a intersecting direction? The atoms will impact, causing them to clump, and have a gravitational pull 2x comparedhttp://cdncache-a.akamaihd.net/items/it/img/arrow-10x10.png to the other atoms. The atoms will clump, starthttp://cdncache-a.akamaihd.net/items/it/img/arrow-10x10.png forming matter, and sorta reform the universe after billions to trillions of years. This causes new universeshttp://cdncache-a.akamaihd.net/items/it/img/arrow-10x10.png, maybe where we came from.

They cannot go in any direction except away from each other. It is spacetime that is expanding, the surface that they are on. Imagine dots on an elastic band, if you pull that elastic band all the dots will move away from each other as the surface expands.

I'll debate in a mature matter if I screwed something up. I'm not a physician, just a student debating the end of universes.

[Kerbart]

All I know is that there is a restaurant at the end of the universe.

[HoloYolo]

That isn't "the cold death" (there's no accepted cosmological term called that anyway, but I assume you meant the Big Freeze, also known as heat death) that's an intermediate step on the way to the end of the universe, for instance the big rip which you say in your third point.

Conservation of energy. Hydrogen fuses to form helium and helium fuses and so on, releasing energy. Takes the same amount go go the other way around, every star uses up a lot of light elements that are needed to form a star.

Newton's laws do not apply in the slightest when talking about cosmology, however even if they did Newton's laws say nothing remotely similar to that. I assume by "states that the universe retreating would have a force going forward at the same speed" you mean every action has an equal and opposite reaction (a force does not go at a speed). This does not in any way at all prevent things expanding from collapsing. One object would pull another object towards itself and vice versa via gravity, causing them both to be attracted to their center point.

They cannot go in any direction except away from each other. It is spacetime that is expanding, the surface that they are on. Imagine dots on an elastic band, if you pull that elastic band all the dots will move away from each other as the surface expands.

A physician has nothing at all to do with this.

[Guest]

A physician has nothing at all to do with this.

That last part should be cosmologist.

- - - Updated - - -

There is no end to the universe. It is expanding meaning that the restaurant is moving at the speed of the universe.

[HoloYolo]

That last part should be cosmologist.

- - - Updated - - -

There is no end to the universe. It is expanding meaning that the restaurant is moving at the speed of the universe.

Something expanding still has an end.

Edited March 28, 2015 by HoloYolo

[YNM]

1. The cold death... Hold up, why would gas disappear? Every time a supernova occurs, the gas from the red supergiant gets flung out, but wouldn't that be enough gas to recycle the gas and make a new star? Same with regular red giants, the planetary nebula should have enough gas for another star.

Each time they explode, they also leave non-gas matter. The amount of gas, then, decreases over very long time - until it's too rarefied to properly collapse.

2. The heat death... Newton's laws of motion wouldn't allow this, as it states that the universe retreating would have a force going forward at the same speed, stopping the universe in it's place.

Nah, problem is, Newton's 3rd law of motion only applies to solids - either this means you count up all the atoms or you don't get it. Also, dark energy isn't your standard force - it's a pressure that presses everything apart. And when there's nothing, they presses spacetime. Newtonian things doesn't hold for spacetime, as much as spacetime is non-newtonian...

3. Ripped apart... But who's to say, if the universe ends this way, how do we know 2 atoms are going in a intersecting direction? The atoms will impact, causing them to clump, and have a gravitational pull 2x comparedhttp://cdncache-a.akamaihd.net/items/it/img/arrow-10x10.png to the other atoms. The atoms will clump, starthttp://cdncache-a.akamaihd.net/items/it/img/arrow-10x10.png forming matter, and sorta reform the universe after billions to trillions of years. This causes new universeshttp://cdncache-a.akamaihd.net/items/it/img/arrow-10x10.png, maybe where we came from.

Because, spacetime is huge (even probably unlimited), and it's expansion isn't restricted by speed of light. Period.

Additional problem : the three are successive, most probably. Unless this happens...

Something expanding still has an end.

Problem is, the cosmological principle, which states everything should be homogeneous and isotropic, holds for the whole universe (as it's certainly larger than 100 Mpc). Having end, or edges, means non-isotropic (you can always point on that end - end is a well-defined direction in that case). The universe must remain unbound - finite or infinite is another story. Having an end in time is also another story.

For those who want to fiddle with it mathematically, try fiddling with friedmann equation and all the other equation derived from it. Quite easy as long as you know calculus and it's still single-component universe. Also, try to read about the concept of scale factor (of course wikipedia won't be satisfactory).

Edited March 28, 2015 by YNM