CMB and the reference point for vacuum energy

  • #1
nomadreid
Gold Member
1,460
147
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.
 

Answers and Replies

  • #2
Drakkith
Staff Emeritus
Science Advisor
20,991
4,811
(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.

(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.
 
  • Like
Likes nomadreid
  • #3
nomadreid
Gold Member
1,460
147
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
Drakkith
Staff Emeritus
Science Advisor
20,991
4,811
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 Threads on CMB and the reference point for vacuum energy

  • Last Post
Replies
4
Views
2K
  • Last Post
Replies
5
Views
2K
  • Last Post
Replies
7
Views
2K
  • Last Post
Replies
5
Views
1K
  • Last Post
2
Replies
37
Views
6K
  • Last Post
Replies
19
Views
3K
  • Last Post
Replies
3
Views
4K
Replies
3
Views
2K
Replies
0
Views
1K
Replies
13
Views
6K
Top