(1 - 2 GM/ r c^2) ^ 1/2 and Big Bang

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Discussion Overview

The discussion revolves around the implications of the equation t1 = t2 (1 - 2 GM/ r c^2)^(1/2) in the context of general relativity and the Big Bang. Participants explore interpretations of the universe's size at the time of the Big Bang and the applicability of Schwarzschild geometry to the universe's structure.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant suggests that if the mass of the universe is 10^52 kg, then r cannot be less than 10^24 meters without leading to imaginary time, proposing that the universe may have started no smaller than this size.
  • Another participant argues that Schwarzschild geometry is not applicable to uniform matter distributions of global extent, challenging the initial premise.
  • A different viewpoint posits that if matter is spherically distributed, vacuum particles might exist outside this distribution at the time of the Big Bang, potentially influencing the dynamics of the early universe.
  • Some participants question the relevance of localized matter models to the actual universe, suggesting that such models do not reflect the universe's true nature.
  • There is a contention regarding the nature of vacuum particles, with one participant asserting that it is plausible for vacuum particles to have wavelengths, while another emphasizes the importance of their global distribution rather than their individual properties.

Areas of Agreement / Disagreement

Participants express differing views on the applicability of general relativity and Schwarzschild geometry to the early universe, with no consensus reached on the interpretations of vacuum particles and their implications for the Big Bang.

Contextual Notes

The discussion highlights limitations in applying certain geometrical models to cosmological scenarios, as well as the unresolved nature of assumptions regarding the distribution and properties of vacuum particles.

kurious
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In general relativity the equation
t1 = t2 ( 1 - 2 GM/ r c ^ 2) ^1/2
is often mentioned.
If the mass, M, is equal to the mass of the universe - 10 ^ 52 kg -
then r cannot be less than 10 ^ 24 metres without invoking
the idea that a time can be imaginary.
But could an equally valid interpretation be that the universe started
out no smaller than 10 ^ 24 metres?
The temperature of the universe one second after the Big Bang is
thought to be 10 ^10 K, and if the temperature of the cosmic microwave
background nowadays,
is extrapolated back from 10^26 metres to 10 ^ 24 metres, this would
give about this temperature [( 10^26 )^4 / (10^24)^4 x 1000 = 10^11 K
( the term of 1000 allows for redshift of cmbr photons).
The above scenario would mean that general relativity does not break
down at the time of the big bang and so quantum gravity might not be
needed to explain the Big Bang.
 
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Shwarzschild geometry applies to vacuum outside a localized spherically symmetric matter distribution. It does not apply to uniform matter distributions of global extent. So, no.
 
What if the matter is spherically distributed and the vacuum is outside the spherical mass distribution.If we associate the vacuum with vacuum particles, at the time of the Big Bang these particles might have existed outside the spherical mass distribution.
If the gap between the quarks and leptons in the spherical mass distribution was smaller than the average wavelength of a vacuum particle then the vacuum particles would have been unable to get into the sphere and so the vacuum would have existed outside it.The vacuum particles would have had to have had a wavelength of about 10^ - 3 metres.This is also the wavelength the cmbr photons would have had to be locked inside the sphere of mass.And it is a MICROWAVE wavelength!
 
kurious said:
What if the matter is spherically distributed and the vacuum is outside the spherical mass distribution.

Then you don't have the universe that we actually have and so the predictions based on your localized matter universe model are irrelevent.
 
DW

Then you don't have the universe that we actually have and so the predictions based on your localized matter universe model are irrelevent.

KURIOUS:
The universe we have now would not necessarily be the universe at the time of the Big Bang.If vacuum particles have wavelengths then what I have said is plausible.
It is most unlikely that vacuum particles do not have wavelengths!
 
kurious said:
DW
KURIOUS:
The universe we have now would not necessarily be the universe at the time of the Big Bang.If vacuum particles have wavelengths then what I have said is plausible.
It is most unlikely that vacuum particles do not have wavelengths!

No, what I am referring to has nothing to do with the fact that they do have wavelengths. It has to do with the fact that their distribution is globally uniform, rather than confined to a sphere of finite extent.
 

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