How is the information of a change in position of a star transmitted?

[KurtLudwig]

TL;DR Summary

How is the information of a change in position of a star transmitted through spacetime? What is the quantum mechanism?

Gravity is the curvature of space time. Stars move relative to each other. How is the information of this change transmitted through spacetime? I have just finished reading "Reality is not what it seems - The journey to quantum gravity" by Carlo Rovelli. (Can the content of a book be discussed on Physics Forums?) Does the information quickly travel from spinfoam to spinfoam? See page 186, the section on spinfoams. It is stated that spinfoams will bend spacetime. But it does not describe the mechanism of changes. Maybe it is beyond the scope of this book. I assume that changes happen at the speed of light.

 

[PeterDonis]

I have just finished reading "Reality is not what it seems - The journey to quantum gravity" by Carlo Rovelli. (Can the content of a book be discussed on Physics Forums?)

Not that book, since it's not a textbook.

 

[PeterDonis]

Gravity is the curvature of space time. Stars move relative to each other. How is the information of this change transmitted through spacetime?

"Transmitted through spacetime" is a misnomer. Spacetime is a 4-dimensional geometry. It doesn't "change" and things don't get "transmitted" through it. It just is. The "motion" of the stars is just the geometric shapes of their worldlines (or "world tubes" if, more realistically, you consider them to have finite size) and how those world tubes are embedded in the overall spacetime geometry. The "information" about the stars is just the spacetime curvature at any particular event, which will be determined by the Einstein Field Equation and the stress-energy that is present.

Does the information quickly travel from spinfoam to spinfoam?

We can't discuss the question on these terms without a valid reference--textbook or peer-reviewed paper--that gives the actual theoretical machinery necessary to address the question in a spin foam theory.

The question can be discussed in the framework of classical GR--that's what I did earlier in this post. But that will have nothing to do with anyone's speculations about quantum gravity. If you're willing to discuss the question as a classical GR question, we can continue to do so in this thread, but in that case it needs to be moved to the relativity forum.