Dark energy and conservation of energy

In summary, dark energy is a mysterious force that is driving the accelerated expansion of the universe, challenging traditional notions of energy conservation. While classical physics holds that energy cannot be created or destroyed, the presence of dark energy complicates this principle, as it appears to provide a constant energy density throughout space, even as the universe expands. This raises questions about the applicability of conservation laws on cosmic scales and suggests that our understanding of energy in the context of the universe may need to be revised.
  • #1
KleinMoretti
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TL;DR Summary
Conservation of energy and different types of dark energy
According to this Sean Carroll article, “https://www.preposterousuniverse.com/blog/2010/02/22/energy-is-not-conserved/
And other threads in here, depending on your definition of energy, dark energy does not violate conservation of energy, my questions is if this is true regardless of the type of dark energy (e.g cosmological constant, quintessence, etc.)

some threads that discussed this topic.
https://www.physicsforums.com/threads/does-spacetime-absorb-energy-in-general-relativity.1013951/


https://www.physicsforums.com/threa...n-in-general-relativity.1060029/#post-7061167
 
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  • #2
Even in a universe without dark energy, energy is not conserved globally. Stress-energy is always locally conserved in GR.

Edit: Also, referring to ”some threads” is unhelpful. Please provide specific examples or we have no way of knowing what you are referring to.
 
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  • #3
Orodruin said:
Even in a universe without dark energy, energy is not conserved globally. Stress-energy is always locally conserved in GR.

Edit: Also, referring to ”some threads” is unhelpful. Please provide specific examples or we have no way of knowing what you are referring to.
yes I understand that but like Sean Carrol points out in his article. there are some people who prefer to say that energy is conserved in an expanding universe. My question was if the type of dark energy used changes anything.
 
  • #4
OCD said:
there are some people who prefer to say that energy is conserved in an expanding universe.
Without a better reference that "some people" there is just no way that we can answer your question sensibly.

One of the things that you will have gotten from that Sean Carroll piece (which is just scratching the surface of a very complex problem) is that in GR conservation of energy is complicated enough that when someone is taking about it the first step is to be clear on exactly what they mean by "conservation of energy".
 
  • #5
Nugatory said:
Without a better reference that "some people" there is just no way that we can answer your question sensibly. One of the things that you will have gotten from that Sean Carroll piece (which is just scratching the surface of a very complex problem) is that in GR conservation of energy is complicated enough that when someone is taking about it the first step is to be clear on exactly what they mean by "conservation of energy".
Okay for example john baez in https://math.ucr.edu/home/baez/physics/Relativity/GR/energy_gr.html says that it depends on your definition of energy to determine whether or not is conserved in GR, more specifically he says that if you accept pseudotensors energy is conserved in GR, does the type of dark energy changes anything here?
 

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