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Are gravitons and gravitational waves analogous to photons and EM radiation?

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Are gravitons and gravitational waves analogous to photons and EM radiation?

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WannabeNewton

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Since gravity bends EM radiation, why would it not also slow down EM radiation?

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WannabeNewton

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Is "curvature" just a figure of speech?

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Nugatory

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The curvature is most certainly not a figure of speech - it's real.

Is "curvature" just a figure of speech?

You can detect curvature by looking for things like parallel lines that intersect (if I draw two parallel lines at the equator and pointing due north they'll intersect at the north pole) and triangles whose interior angles don't add to 180 degrees.

It's something of a jump to conclude that the presence of these curvature effects means that spacetime has to be "something" instead of "nothing". All we really have is a mathematical object (the "metric tensor") that tells us the distance between two nearby points; large-scale effects like the intersecting or not of parallel lines are derived from the metric. Some metrics correspond to flat manifolds and others to curved ones; neither tell us much about whether there's something there to curve.

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Drakkith

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This is highly dependent on what "nothing" means.

Is "curvature" just a figure of speech?

Consider that we cannot detect spacetime, we cannot measure it, cannot touch it, etc. We can only detect and interact with things within spacetime, which is why its called the "framework" that everything sits within. If you want to go ahead and say that spacetime is "something", then feel free. Just realize that your definition of "nothing" and "something" may be different than someone else's. In the end whether you call it nothing or not changes, well, nothing. It's just arguing over definitions.

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