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#55
Jan2206, 01:18 AM

Sci Advisor
PF Gold
P: 3,274

Astrophysics is the science of understanding 'what goes on up there' (astro) by understanding 'what goes on down here' (physics)  in the laboratory. Rather than beginning to understand the Unruh effect of the expansion of the universe start with the laboratory.
The Unruh effect is observed for noninertial observers, we are noninertial observers. This effect predicts that empty vacuum in a suported laboratory should have a nonnegative density in that frame of reference. I make this Unruh vacuum density to be ~ 10^{113} gms/cc, as a point of interest SSC predicts a vacuum density near the Earth of ~ 10^{9} gms/cc, caused by reconciling the divergence of its two field equation solutions for a gravitational field. Garth 


#56
Jan2206, 02:24 AM

Sci Advisor
P: 1,047

Thank you George. I was thinking about my question you tried to answer and I am not sure to understand this:



#57
Jan2206, 11:38 AM

Mentor
P: 6,248

Other examples could start with an excited field for the inertial observer, and then there would be backreaction. Regards, George 


#58
Jan2306, 01:40 AM

P: 167

Forum,
As I have had a recent post in this thread removed for being too speculative, I wish to resubmit the ideas presented in the removed post as questions. I will include a couple of citations in reference to these questions that I hope will allow it to get by the censors as being in the ballpark of opinions that are "currently held by the scientific community." Here goes: In this citation we read: And in this citation: So, with these references in mind, I will reitterate the main concepts in my deleted post: It seems to me that the current thinking in dark energy is to look for an energy density between the galaxies to explain it. My questions are: What if the energy density between galaxies is irrelevent? What if the galaxies are apparently simply falling outward toward the CEH, rather than being forced outward from an internal pressure? What if due to a quirk of relativity, the universe appears to be accelerating from all reference frames, but may or may not actually be accelerating? What if the apparent expansion acceleration is simply caused by relativistic effects of very distant mass in motion? Could these proposed relativistic effects cause an apparent infinite density to the CEH that essentially causes it to behave much like a black hole event horizon in that it emits Unruh and other radiation (that we perceive as the CMBR) and gravity/acceleration (that we perceive as the effects of dark energy)? That is, (in deference to my citations) could gravity itself be a relativistic effect in the extrenum of the cosmological event horizon? Note: This post has been edited by ubavontuba 


#59
Jan2306, 02:08 AM

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PF Gold
P: 3,274

From my calculations above is it not clear that any Unruh coming from the CEH is many orders of magnitude smaller than that required for the CMB?
Garth 


#60
Jan2306, 02:57 AM

P: 167

Anyway, let's think about what's happening at the CEH. Isn't mass heading (falling?) into it? Now let's think about the CEH like how we might think about black holes. In this case, let's think about black holes with halos of matter around and falling into them. They emit a lot more energy in IR than simply the Unruh and Hawking radiation, don't they? P.S. It looks to me like the expansion model must still hold, but the universe needn't be quite as young or old as we might measure. Also, it isn't the concept of expansion that is in question, but rather the acceleration effect known as dark energy. In other words, is it possible that even a linear expansion might be perceived as an acceleration in the extrenum of relativity and the CEH? 


#61
Jan2306, 08:19 PM

P: 1,308

I wonder if acceleration radiation is the same as vacuum energy of the cosmological constant? If so, then it would seem that since zero acceleration gives zero energy density, then inertial frames traveling arbitrarily close to any point in space (even with zero velocity) would feel no temperature and would prove that there is no zero point energy/vacuum energy/cosmological constant. I could use some clarification on this. Thank you. 


#62
Jan2406, 01:19 AM

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PF Gold
P: 3,274

Garth 


#63
Jan2406, 09:46 AM

P: 1,308




#64
Jan2406, 11:59 AM

Sci Advisor
PF Gold
P: 3,274

Garth 


#65
Jan2406, 04:11 PM

P: 1,308

This would give us a connection between the properties of spacetime and the properties of matter, so that QFT might lead to QG. 


#66
Feb906, 10:52 PM

P: 167

Forum,
Hey, take a look at this article in the current issue of NewScientist! Apparently life inside a black hole, isn't quite such an absurd notion afterall. 


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