CMB and the reference point for vacuum energy

In summary, the conversation discusses the role of the Cosmic Background Radiation (CMB) in various theories, such as the Casimir effect and the flatness of the universe. The CMB may contribute to the pressure on plates in the Casimir effect, but can be easily blocked. In terms of the flatness of the universe, the CMB is taken into account in models, but its exact role is not clear. The discussion also raises the question of whether space would be slightly curved if only vacuum energy, and not other forms of mass-energy, were present. However, this is a complex topic and the exact role of the CMB in shaping space is not fully understood.
  • #1
nomadreid
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From the basic definition of vacuum energy as being tied in with the Uncertainty principle, I would expect this not to include the Cosmic Background Radiation. Right? On the other hand, in figuring out
(a) the Casimir effect, one attributes the force to the field between the plates carrying less energy than the vacuum... but the CMB is always there as well, so one would imagine that this would contribute to the pressure on the plates
(b) why the observable universe is nearly spatially flat and how inflation smooths it down, it is not clear whether this takes the CMB into consideration or not.
Thanks for any attempts to clear up my confusion.
 
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  • #2
nomadreid said:
(a) the Casimir effect, one attributes the force to the field between the plates carrying less energy than the vacuum... but the CMB is always there as well, so one would imagine that this would contribute to the pressure on the plates

The CMB can easily be blocked by anything that blocks microwave radiation, so this isn't a problem.

nomadreid said:
(b) why the observable universe is nearly spatially flat and how inflation smooths it down, it is not clear whether this takes the CMB into consideration or not.

Yes, the models take the CMB into account. Well, not for inflation, since the CMB didn't exist at the time of inflation, but the flatness of the universe has to include the energy density of the CMB and everything else. As far as I know at least.
 
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  • #3
Thanks very much, Drakkith. So, when one refers to the negative energy between the plates, that is in reference only to the vacuum energy. This brings me to ask whether, then, since space is very nearly flat with the CMB and gravity and dark energy and so forth included, then if only the vacuum energy but not the CMB , matter, dark energy, etc. were present (if this condition makes sense), space would then be slightly curved (in the opposite way to its curvature in the presence of other mass-energy)?
 
  • #4
nomadreid said:
This brings me to ask whether, then, since space is very nearly flat with the CMB and gravity and dark energy and so forth included, then if only the vacuum energy but not the CMB , matter, dark energy, etc. were present (if this condition makes sense), space would then be slightly curved (in the opposite way to its curvature in the presence of other mass-energy)?

I confess I don't know. The details of the shape of space are a bit beyond me.
 

Related to CMB and the reference point for vacuum energy

1. What is CMB and how is it related to the reference point for vacuum energy?

CMB stands for Cosmic Microwave Background, and it is the leftover radiation from the Big Bang that fills the entire universe. The reference point for vacuum energy refers to the lowest possible energy state of empty space. These two concepts are related because the CMB provides evidence for the existence of vacuum energy, as it is the energy that fills the empty space of the universe.

2. How was the reference point for vacuum energy discovered?

The reference point for vacuum energy was first proposed by Albert Einstein in his theory of general relativity. However, it was not until the 1990s that scientists discovered the existence of vacuum energy through observations of the acceleration of the expansion of the universe. This was confirmed by the observations of the CMB, which showed that the universe is filled with a uniform energy field.

3. How does the reference point for vacuum energy affect the expansion of the universe?

The reference point for vacuum energy is thought to be responsible for the acceleration of the expansion of the universe. This is because it exerts a repulsive force that counteracts the gravitational pull of matter, causing the expansion of the universe to accelerate.

4. Can the reference point for vacuum energy be harnessed for practical use?

Currently, there is no known practical application for harnessing the reference point for vacuum energy. However, some scientists are studying the possibility of using vacuum energy as a potential source of renewable energy in the future.

5. How does the study of CMB and the reference point for vacuum energy contribute to our understanding of the universe?

The study of CMB and the reference point for vacuum energy provides valuable insights into the composition and evolution of the universe. It helps us understand the expansion of the universe, the role of dark energy, and the overall structure of the cosmos. It also allows us to test and refine our theories about the origins and fate of the universe.

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