Does GR really post-dict the big bang?

  • Thread starter Thread starter PerpStudent
  • Start date Start date
  • Tags Tags
    Big bang Gr
PerpStudent
Messages
30
Reaction score
0
Do the GR tensor equations have specific solutions that post-dict the big bang? I have seen references to GR providing a theoretical basis for the big bang. Exactly what is the nature of this theoretical basis? If the mathematics for this is too complex for posting on this forum, I would appreciate a link that would provide more information about this. Thanks in advance.
 
Physics news on Phys.org
Yes, there is a solution to the Einstein field equations that describes the big-bang. It is called the Friedmann–Lemaître–Robertson–Walker metric, and it's not really that complicated. Here's a link to get started. It reduces to a set of simple ordinary differential equations called the Friedmann equations.
 
Thank you. That's very helpful.
 

Thread 'I don't see how a black hole's event horizon can be crossed'

OK, so this has bugged me for a while about the equivalence principle and the black hole information paradox. If black holes "evaporate" via Hawking radiation, then they cannot exist forever. So, from my external perspective, watching the person fall in, they slow down, freeze, and redshift to "nothing," but never cross the event horizon. Does the equivalence principle say my perspective is valid? If it does, is it possible that that person really never crossed the event horizon? The...
View full post »

Thread 'Synchronizing clocks in an inertial frame if light is anisotropic'

ASSUMPTIONS 1. Two identical clocks A and B in the same inertial frame are stationary relative to each other a fixed distance L apart. Time passes at the same rate for both. 2. Both clocks are able to send/receive light signals and to write/read the send/receive times into signals. 3. The speed of light is anisotropic. METHOD 1. At time t[A1] and time t[B1], clock A sends a light signal to clock B. The clock B time is unknown to A. 2. Clock B receives the signal from A at time t[B2] and...
View full post »

Thread 'Is the variation of the metric ##\delta g_{\mu\nu}## a tensor?'

From $$0 = \delta(g^{\alpha\mu}g_{\mu\nu}) = g^{\alpha\mu} \delta g_{\mu\nu} + g_{\mu\nu} \delta g^{\alpha\mu}$$ we have $$g^{\alpha\mu} \delta g_{\mu\nu} = -g_{\mu\nu} \delta g^{\alpha\mu} \,\, . $$ Multiply both sides by ##g_{\alpha\beta}## to get $$\delta g_{\beta\nu} = -g_{\alpha\beta} g_{\mu\nu} \delta g^{\alpha\mu} \qquad(*)$$ (This is Dirac's eq. (26.9) in "GTR".) On the other hand, the variation ##\delta g^{\alpha\mu} = \bar{g}^{\alpha\mu} - g^{\alpha\mu}## should be a tensor...
View full post »

Similar threads

I Time Before Big Bang: Relational Dynamics & Singularities
Replies
2
Views
2K
I Big bang balloon?
Replies
5
Views
257
I Big bang at the edges of the Universe?
Replies
25
Views
3K
B Big Bang and Infinite Universe
Replies
20
Views
1K
A Is gravity simply an interaction in the gauge theory of gravity?
2
Replies
50
Views
4K
B Big Crunch, Big Bang and information loss
2
Replies
56
Views
7K
Were Hawking Radiation & Singularity Theorem Controversial in 1965?
Replies
2
Views
2K
A What is the concept of no prior geometry in GR?
Replies
20
Views
3K
I Does Feynman's Work on Gravitons Clarify Quantum Gravity?
Replies
1
Views
2K
I Coordinate System for Minkowskian Spacetime Relative to Event
Replies
8
Views
2K

Hot Threads

Recent Insights

Back
Top