- #1

MeJennifer

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**"Light cones tipping over"**

A common phrase used to show alleged time travel solutions in GR.

Even a person like Kip Thorne uses it.

But my question is, is that an accurate representation of GR in strong gravitational fields?

The Schwarzschild metric expressed using the Eddington-Finkelstein coordinates show those "light cones tipping over", and eventually the radial and time coordinates reverse.

But this reversal, and even the tipping over seems to me a peculiarity of the choice of coordinates. It seems to me that it is assumed that there is a particular relationship between the radial and time coordinate.

That seems to be a rather liberal interpretation of the metric.

Afteral nothing in the Minkowskian metric of ds

^{2}= dt

^{2}- dr

^{2}implies that if dt

^{2}becomes negative it must be considered space and if dr

^{2}becomes negative it must be considered time.

Any comments or explanations?

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