Deviations of conservation laws in cosmological evolution?

In summary, energy is not conserved in General Relativity in the sense of a well-defined global energy, but local energy conservation still holds. No observations have shown deviations from strict conservation laws in the evolution and formation of large scale structures. The effects of tidal forces from spacetime expansion may be considered in some articles about the study of galaxy and cluster evolutions, but it is not a significant factor.
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Suekdccia
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Deviations of conservation laws in the context of cosmological evolution?
If energy is "not conserved" in General Relativity (or at least, it is difficult to define it) in the context of an expanding accelerating spacetime (like it happens in our Universe), are there any observations of deviations from the strict conservation laws in the evolution and formation of large scale structures (like clusters or superclusters of galaxies for instance)?

For example, in some articles about the study of galaxies and clusters evolutions and formations, sometimes the effects of the "tidal force" from spacetime expansion is considered... Has the expansion changed the energy or momentum of these systems somehow?
 
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Suekdccia said:
If energy is "not conserved" in General Relativity
This doesn't mean what it seems to mean.

When you think of "energy conservation", you're probably thinking of local energy conservation: roughly speaking, that energy can't be created or destroyed in any local process. That is still true in GR; its mathematical expression is that the covariant divergence of the stress-energy tensor is zero.

What "energy is not conserved" in GR actually means is that, except for certain special cases (of which our expanding universe is not one), there is no well-defined global energy that is conserved. But that doesn't mean you can make a perpetual motion machine or get free energy from nothing. All it means is that general curved spacetimes don't have a certain mathematical property that many physicists think it would be "nice" to have.

Suekdccia said:
are there any observations of deviations from the strict conservation laws in the evolution and formation of large scale structures (like clusters or superclusters of galaxies for instance)?
No. These are all local processes and, as above, local energy conservation holds in GR. For example, the energy radiated away as a bound system (say a star) forms is exactly equal to the decrease in the externally measured mass of the system.

Suekdccia said:
in some articles about the study of galaxies and clusters evolutions and formations, sometimes the effects of the "tidal force" from spacetime expansion is considered
Can you give a reference?
 
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1. What are conservation laws in cosmological evolution?

Conservation laws refer to fundamental principles that govern the behavior of physical systems in the universe. These laws state that certain quantities, such as energy, momentum, and angular momentum, remain constant over time in a closed system.

2. How do conservation laws apply to cosmological evolution?

In cosmological evolution, conservation laws play a crucial role in understanding the behavior of the universe. These laws help us understand how energy, matter, and other physical quantities are conserved and transformed as the universe evolves.

3. What are some examples of deviations from conservation laws in cosmological evolution?

One example of a deviation from conservation laws in cosmological evolution is the phenomenon of dark energy, which is believed to be responsible for the accelerating expansion of the universe. This violates the law of conservation of energy, as it suggests that energy is being created in the universe.

4. How do scientists explain these deviations from conservation laws?

Scientists are still working to fully understand the deviations from conservation laws in cosmological evolution. Some theories propose the existence of new fundamental forces or particles that could explain these deviations, while others suggest modifications to our current understanding of conservation laws.

5. What impact do deviations from conservation laws have on our understanding of the universe?

The deviations from conservation laws in cosmological evolution challenge our current understanding of the universe and push us to develop new theories and models to explain these phenomena. They also highlight the need for further research and exploration in order to gain a deeper understanding of the fundamental principles that govern our universe.

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