How are electromagnetism and space-time related, and can electromagnetic fields exert a force on space-time?
A popular science fiction technology is to use electromagnetic fields to manipulate the local geometry of space-time. All that general relativity says is that any form of energy can cause space-time to become curved. Too much curvature and you may end up with black holes or worm holes. The form of the energy can be anything; raw mass, the energy latent in electromagnetic fields, neutrinos etc. So, electromagnetic fields are not intimately related to space-time any more than mass is; its just another form of energy that can serve to generate curvature via its own gravitational field. The problem is that, because gravity is so weak, you have to concentrate a LOT of energy in one place in order to make any significant change in the local gravity. An entire planet like earth has barely enough gravity to wing a tug-of-war with a toy magnet over a paper clip. Copyright 1997 Dr. Sten Odenwald Return to Ask the Astronomer.
