B Time, Space, Fields, Spacetime & General Relativity

  • B
  • Thread starter Thread starter Immortal68
  • Start date Start date
  • Tags Tags
    Fields Space Time
Immortal68
Messages
4
Reaction score
0
TL;DR Summary
Can time and space be thought of fields?
Can time and space be thought of fields? And if so, how can this affect spacetime? And then what would this mean for affect general relativity?
 
Physics news on Phys.org
Immortal68 said:
Can time and space be thought of fields?

I have no idea what that would even mean, so I think the answer is no.
 
  • Like
Likes Vanadium 50
Immortal68 said:
Summary:: Can time and space be thought of fields?

Can time and space be thought of fields?
A field is something that has a value at each point in spacetime. So it would be quite circular to define spacetime as a field.
 
What we call spacetime actually is a manifold equiped with a metric, which is a tensor field.

In John Stachels words: "no metric, no nothing."
 
  • Like
Likes vanhees71 and Dale
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...
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...
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...

Similar threads

Back
Top