Is it true than general relativity can be deduced from a max

Garrulo
Messages
61
Reaction score
0
Is it true than general relativity can be deduced from a maximum mass density for matter?
 
Physics news on Phys.org
Garrulo said:
Is it true than general relativity can be deduced from a maximum mass density for matter?
No!
 
Garrulo said:
Is it true than general relativity can be deduced from a maximum mass density for matter?

What makes you think it can be? Did you read about this somewhere?
 
PeterDonis said:
What makes you think it can be? Did you read about this somewhere?
I can imagine it was a crackpot's fault. It makes a nice crackpot argument to say Einstein used maximum principles in getting special and general theories of relativity.
 
Threads like this one are the reason we have a rule about citing sources.

I'm closing this thread now, and will reopen it if the original poster asks me by PM to reopen it so that the source can be posted. Without that information, there's not much to say that Shyan didn't already say in #2 of the thread.
 
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...
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...
Back
Top