PeterDonis's latest activity
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PeterDonis replied to the thread Undergrad Does the steady-state model resolve Olbers' paradox?.So far in this thread we have not seen any mathematical model that does not satisfy the EFE. If you are claiming that the metric... -
PeterDonis replied to the thread Undergrad Does the steady-state model resolve Olbers' paradox?.I already did. I'm not going to repeat myself.
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PeterDonis replied to the thread Undergrad Does the steady-state model resolve Olbers' paradox?.Bonnor himself does not make the claim that that metric is the metric of the steady-state model. He references a paper by McCrea that...
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PeterDonis replied to the thread Undergrad Does the steady-state model resolve Olbers' paradox?.You are correct that the metric you quoted describes an FLRW metric, since de Sitter spacetime, which is what that metric describes, is...
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PeterDonis replied to the thread Undergrad Does the steady-state model resolve Olbers' paradox?.It turns out that Ben Crowell wrote an Insights article on the steady-state model...
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PeterDonis replied to the thread Undergrad Does the steady-state model resolve Olbers' paradox?.The metric you cite, equation 1.1 in the Bonnor paper, does specify a behavior of the scale factor. It's not just "the FLRW metric"...
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PeterDonis replied to the thread Undergrad Does the steady-state model resolve Olbers' paradox?.What is your basis for this claim?
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PeterDonis reacted to Ibix's post in the thread Undergrad Does the steady-state model resolve Olbers' paradox? with
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If it doesn't satisfy the EFEs it won't satisfy the Friedmann equations either. It feels like a bit of a stretch to classify a spacetime... -
PeterDonis replied to the thread Undergrad "Scientists have measured space to be flat to high accuracy".Moderator's note: A subthread on the steady-state model has been moved to its own thread here...
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PeterDonis replied to the thread Undergrad "The wavefunction never collapses".There are restrictions, at least according to string theorists, regarding what numbers of dimensions allow solutions, yes. But the point...
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PeterDonis replied to the thread Undergrad "The wavefunction never collapses".Not really, no. The massless spin-2 field QFT approach, which is what you're describing, still has to start with an assumption of some...
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PeterDonis reacted to Ibix's post in the thread Undergrad Does the steady-state model resolve Olbers' paradox? with Like.
Unfortunately, the paper then shows that the equations of motion of the cosmological fluid in such a system are completely undetermined...
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PeterDonis reacted to Demystifier's post in the thread Graduate Why is there gauge freedom in ADM formalism? with Like.
The dependence on lapse and shift is hidden in the ADM Hamiltonian and momentum constraints. That's because these constraints are...
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PeterDonis replied to the thread Undergrad "The wavefunction never collapses".Without an actual theoretical model to use to do the calculation, this question is not answerable.
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PeterDonis replied to the thread Undergrad "The wavefunction never collapses".There's a difference, though. We know how to quantize everything that isn't gravity: just use the standard framework of quantum field...