Can Dark Matter just be vacuum fluctuations?

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Discussion Overview

The discussion revolves around the concept of modeling dark matter as a result of vacuum fluctuations, drawing parallels to the Casimir Effect. Participants explore the implications of such a model, its compatibility with existing theories, and the distinctions between dark matter and dark energy.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation
  • Mathematical reasoning

Main Points Raised

  • One participant proposes the idea of dark matter being modeled as pressure from vacuum fluctuations, likening it to a cosmological-scale Casimir Effect.
  • Another participant highlights that while quantum field theory estimates energy density from vacuum fluctuations, the estimates are significantly higher than observed, raising questions about the validity of the calculation.
  • A participant points out the confusion between dark matter and dark energy, clarifying that vacuum fluctuations are more related to dark energy.
  • It is argued that the pressure from vacuum fluctuations would lead to repulsive gravity, which is characteristic of dark energy, not dark matter, which must exhibit attractive gravity.
  • One participant suggests that if the calculated matter is consistently twice the ordinary matter, it may indicate a missing translation factor, potentially reducing the perceived amount of dark matter.
  • Another participant counters this by asserting that the gravitational attraction of regular matter is well understood and measured, implying that there is no additional factor affecting the gravitational constant.
  • There is a discussion about the mathematical implications of equations involving the reduced Compton wavelength and Planck constant, with some participants expressing confusion over the relevance of these factors to the dark matter discussion.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the viability of modeling dark matter as vacuum fluctuations. There are competing views regarding the nature of dark matter and the implications of gravitational measurements, indicating ongoing disagreement and uncertainty.

Contextual Notes

The discussion highlights limitations in understanding the relationship between vacuum fluctuations and dark matter, as well as the potential for misinterpretation of gravitational measurements. The complexity of the mathematical arguments presented also suggests that further clarification may be needed.

bbbl67
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Has there been any theories proposed that model Dark Matter as just the pressure from vacuum fluctuations? It would be just a big cosmological-scale version of the Casimir Effect, where instead of using a couple of plates separated by microns, we're using the gravity wells of galaxies to create low-pressure regions of space, separated across thousands or millions of light-years.
 
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Quantum field theory allows to estimate an energy density of those quantum fluctuations - but that estimate is a factor 10120 too high. It is an open question if
(a) that calculation makes sense at all,
(b) there is some particular reason why our estimate is way off, or
(c) we do not understand the problem.

Either way, dark energy is not just a casimir-like effect, because that is absolutely negligible on cosmological distances.
 
Are we talking dark matter or dark energy here?
 
Oh, good point. The QFT vacuum doesn't have any connection to dark matter so I read "dark energy" somehow.
 
bbbl67 said:
Has there been any theories proposed that model Dark Matter as just the pressure from vacuum fluctuations?

No, because that pressure behaves the wrong way to account for dark matter. The pressure due to vacuum fluctuations causes repulsive gravity--it behaves like dark energy. But whatever it is that dark matter turns out to be, it must have attractive gravity, like ordinary matter, because it's the presence of "extra" attractive gravity--i.e., more of it than can be accounted for by the matter we can see--that signals the presence of dark matter.
 
PeterDonis said:
But whatever it is that dark matter turns out to be, it must have attractive gravity, like ordinary matter, because it's the presence of "extra" attractive gravity--i.e., more of it than can be accounted for by the matter we can see--that signals the presence of dark matter.
Not necessarily, if our calculated matter continues to = ordinary matter * 2 Pi (+/-3%) we may just be missing a translation factor of 2 Pi somewhere. If this turned out to be the case a simple correction would lead to much less dark matter along with minimal attractive gravity.

It's interesting to note that basic equations when solved for m, that contain the reduced Compton wavelength XOR the reduced Planck constant have an implicit 2 Pi present in their most basic forms UNLESS the equation includes phase velocity then things will be reversed and 2 Pi becomes implicit in the other equation forms where (standard Compton wavelength AND standard Planck constant) OR (reduced Compton wavelength AND reduced Planck constant) appear. So, coming around full circle, equations that contain the reduced Compton wavelength XOR the reduced Planck constant will NOT have an implicit 2Pi present in their basic forms if they are solved for m and phase velocity is present.
 
Laurie K said:
Not necessarily, if our calculated matter continues to = ordinary matter * 2 Pi (+/-3%) we may just be missing a translation factor of 2 Pi somewhere. If this turned out to be the case a simple correction would lead to much less dark matter along with minimal attractive gravity.
No, that does not work. We know the gravitational attraction between regular matter very well - we can measure it in a lab. The gravitational constant is measured in that way. There is no additional factor around.
Laurie K said:
It's interesting to note that basic equations when solved for m, that contain the reduced Compton wavelength XOR the reduced Planck constant have an implicit 2 Pi present in their most basic forms UNLESS the equation includes phase velocity then things will be reversed and 2 Pi becomes implicit in the other equation forms where (standard Compton wavelength AND standard Planck constant) OR (reduced Compton wavelength AND reduced Planck constant) appear. So, coming around full circle, equations that contain the reduced Compton wavelength XOR the reduced Planck constant will NOT have an implicit 2Pi present in their basic forms if they are solved for m and phase velocity is present.
That does not make sense, but it is completely irrelevant anyway - the mismatch of matter and gravitational forces is purely based on classical mechanics.
 

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