I Dark energy and conservation of energy

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The discussion revolves around the complexities of energy conservation in the context of dark energy and general relativity (GR). It highlights that energy conservation is not globally applicable in an expanding universe, as noted by Sean Carroll and John Baez, who emphasize that definitions of energy play a crucial role in these discussions. The type of dark energy, such as cosmological constant or quintessence, raises questions about its impact on energy conservation. Participants stress the need for clarity in definitions and references when discussing these concepts. Ultimately, the conversation underscores the intricate relationship between dark energy and the conservation of energy in GR.
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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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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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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.
 
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".
 
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?
 
The Poynting vector is a definition, that is supposed to represent the energy flow at each point. Unfortunately, the only observable effect caused by the Poynting vector is through the energy variation in a volume subject to an energy flux through its surface, that is, the Poynting theorem. As a curl could be added to the Poynting vector without changing the Poynting theorem, it can not be decided by EM only that this should be the actual flow of energy at each point. Feynman, commenting...