# Laser and GR

How to change the curvature of space-time around a very powerful laser beam?

Dale
Mentor
2020 Award
Look up pp-wave spacetimes, particularly the axisymmetric pp-wave spacetimes.

Spinning disk

How lame space time around a rotating metal disk?

Thank you.

Dale
Mentor
2020 Award

Huh? What is a lame spacetime?

"lame" I mean curvature of spacetime.

I am sorry but this text translate Google from Slovak languige.

tiny-tim
Homework Helper
Hi jaiii !

Any rotating object "drags" spacetime around with it …

see http://en.wikipedia.org/wiki/Frame-dragging" [Broken]

btw, "lame" means unable to walk properly ("he is lame", "he has a lame leg" "lame-duck president"), and also is used figuratively to mean something that doesn't work properly ("a lame excuse")

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Dale
Mentor
2020 Award
In addition to the information about how a rotating mass affects the curvature of spacetime you may want to read about how using rotating coordinates affects things in the absence of a rotating mass:

http://www.phys.uu.nl/igg/dieks/rotation.pdf [Broken]

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