# Thread: Does the expansion of the universe create endless energy?

1. I hope this start of a thread will be an argument between two sides
Side number 1, in order to have expansion there has to be energy, therefore creating endless energy.
Side number 2, the expansion of empty space would not require anything in order to expand.

And one last question that I think is interesting, Suppose you have a rubber ball close to the border of the universe, if you somehow teleported the ball outside the border, then would more space be created in the universe? I think this leads to the possibility to no end to the universe, because if there was a border then it would be constantly broken by space rocks exiting the universe.

2.

3. Originally Posted by frumpydolphin
I hope this start of a thread will be an argument between two sides
Side number 1, in order to have expansion there has to be energy, therefore creating endless energy.
Side number 2, the expansion of empty space would not require anything in order to expand.
2. Expansion does not require energy.

However, it has recently been discovered that the expansion is accelerating. One possible explanation is that there is (dark) energy associated with empty space. If so, then as space expands, it creates more dark energy.

Suppose you have a rubber ball close to the border of the universe,
There is no border. The universe is either infinite or finite but unbounded. For the latter, consider the surface of the Earth as a 2D analogy: it has a finite area but no edge.

4. Originally Posted by Strange
Originally Posted by frumpydolphin
I hope this start of a thread will be an argument between two sides
Side number 1, in order to have expansion there has to be energy, therefore creating endless energy.
Side number 2, the expansion of empty space would not require anything in order to expand.
2. Expansion does not require energy.

However, it has recently been discovered that the expansion is accelerating. One possible explanation is that there is (dark) energy associated with empty space. If so, then as space expands, it creates more dark energy.

Suppose you have a rubber ball close to the border of the universe,
There is no border. The universe is either infinite or finite but unbounded. For the latter, consider the surface of the Earth as a 2D analogy: it has a finite area but no edge.

Hi!

Just a few things... first of all, there is no such thing as empty space in quantum mechanics, all space has some associated matter or energy and even if you tried to make a pure vacuum, you'd still find residual energy called zero point energy.

Also, I think it is thought that as the universe expands, more energy is released into the vacuum. This release of vacuum energy is due to the cosmological constant.

I hope that clears a few misconceptions here!

5. I hate quantom mechanics, I honestly think its one of those dream like topics, this is pretty much how it started what if there were 2 of everything.

6. Originally Posted by Strange
Originally Posted by frumpydolphin
I hope this start of a thread will be an argument between two sides
Side number 1, in order to have expansion there has to be energy, therefore creating endless energy.
Side number 2, the expansion of empty space would not require anything in order to expand.
2. Expansion does not require energy.

However, it has recently been discovered that the expansion is accelerating. One possible explanation is that there is (dark) energy associated with empty space. If so, then as space expands, it creates more dark energy.
Arguably, an expanding universe requires the energy-momentum that is implied by the metric via the Einstein equation.

With regards to the opening post, there is no room for debate. The metric of the expanding universe unequivocally determines the energy-momentum.

7. Originally Posted by KJW
Originally Posted by Strange
Originally Posted by frumpydolphin
I hope this start of a thread will be an argument between two sides
Side number 1, in order to have expansion there has to be energy, therefore creating endless energy.
Side number 2, the expansion of empty space would not require anything in order to expand.
2. Expansion does not require energy.

However, it has recently been discovered that the expansion is accelerating. One possible explanation is that there is (dark) energy associated with empty space. If so, then as space expands, it creates more dark energy.
Arguably, an expanding universe requires the energy-momentum that is implied by the metric via the Einstein equation.

With regards to the opening post, there is no room for debate. The metric of the expanding universe unequivocally determines the energy-momentum.

It actually comes from the cosmological constant term in Einsteins equations.

8. Originally Posted by Chesslonesome
It actually comes from the cosmological constant term in Einsteins equations.
No, the metric of the spacetime determines the full energy-momentum (including vacuum energy-momentum).

9. Originally Posted by KJW
Originally Posted by Chesslonesome
It actually comes from the cosmological constant term in Einsteins equations.
No, the metric of the spacetime determines the full energy-momentum (including vacuum energy-momentum).

No, it's the cosmological constant which drives expansion.

10.

The standard concordance model of the Universe is based on the cosmological constant as the driver of accelerating expansion
The cosmological constant provides the acceleration. It is not the reason for the whole of the expansion.

Without a cosmological constant the universe would still be expanding, but that expansion would be decelerating due to gravity. So the cosmological constant does not drive the expansion, it drives the acceleration of the expansion.

12. Originally Posted by Chesslonesome
Originally Posted by KJW
No, the metric of the spacetime determines the full energy-momentum (including vacuum energy-momentum).
No, it's the cosmological constant which drives expansion.
The definition of the Einstein tensor and the Einstein equation is an expression of the energy-momentum tensor in terms of the metric.

13. Originally Posted by SpeedFreek

The standard concordance model of the Universe is based on the cosmological constant as the driver of accelerating expansion

If we knew what started big bang acceleration (something which I think has to do with the uncertainty principle), then we would have a full model. The things which drives acceleration is the cosmological constant, which does mean as the universe expands, more energy is released into the vacuum.

14. Originally Posted by Chesslonesome
Originally Posted by SpeedFreek

The standard concordance model of the Universe is based on the cosmological constant as the driver of accelerating expansion

If we knew what started big bang acceleration (something which I think has to do with the uncertainty principle), then we would have a full model. The things which drives acceleration is the cosmological constant, which does mean as the universe expands, more energy is released into the vacuum.
The OP made no mention of accelerated expansion.

15. Originally Posted by KJW
Originally Posted by Chesslonesome
Originally Posted by SpeedFreek

The standard concordance model of the Universe is based on the cosmological constant as the driver of accelerating expansion

If we knew what started big bang acceleration (something which I think has to do with the uncertainty principle), then we would have a full model. The things which drives acceleration is the cosmological constant, which does mean as the universe expands, more energy is released into the vacuum.
The OP made no mention of accelerated expansion.

I didn't think I needed to because I linked to the page.

16. Originally Posted by Chesslonesome
Originally Posted by KJW
The OP made no mention of accelerated expansion.
I didn't think I needed to because I linked to the page.
The point is that only the acceleration of the expansion is determined by the cosmological constant, not the expansion itself, which was what the OP asked about.

17. Originally Posted by Chesslonesome
Originally Posted by SpeedFreek

The standard concordance model of the Universe is based on the cosmological constant as the driver of accelerating expansion

If we knew what started big bang acceleration (something which I think has to do with the uncertainty principle), then we would have a full model. The things which drives acceleration is the cosmological constant, which does mean as the universe expands, more energy is released into the vacuum.
But the expansion was decelerating for 7-8 billion years, before it started to accelerate. During that time, the cosmological constant was not driving the acceleration of the expansion, but the universe was still expanding.

18. Originally Posted by KJW
Originally Posted by Chesslonesome
Originally Posted by KJW
The OP made no mention of accelerated expansion.
I didn't think I needed to because I linked to the page.
The point is that only the acceleration of the expansion is determined by the cosmological constant, not the expansion itself, which was what the OP asked about.
you are trying to reason with one of the most hardened cranks on the internet.

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