Effect of high intensity electric and magnetic fields on gravity

[bwanaaa]

15 years ago this was published:

http://www.scientificamerican.com/article/do-electric-charges-and-m/

They refer to the "Reissner-Nordstrom" solution to Einstein's gravitational field equations. Basically what gravity would do near the surface of a very strong VanDe Graaf generator. They also mention the solution describing the special case in which the net electric charge is zero is the famous "Schwarzschild solution" to the gravitational field equations.

But I am more interested in what progress has been made in measuring the effect of a strong electric field. Is the prediction that it would increase gravity? or decrease it? or change the curvature of space so that gravity changes differently than the square of the radius between two masses?

Physical examples are not cited as they would be hard to find. But arent quasars a logical source of high intensity EM emissions? So the obvious question is:
Does light bend around a quasar differently than it bends around an equivalently massive but non radiating object?

 

[Biftheunderstudy]

We don't really expect large electric fields to exist except perhaps locally since a charged body will quickly find it's opposite and neutralize. We do see some pretty big magnetic fields. Basically, the energy associated with either field goes into the stress-energy tensor from GR and does all the stuff we expect from gravity.

That said, a quasar is really a supermassive black hole, and the emissions and magnetic field associated with it are really linked to the accretion disk around it. I'd have to work out the relative strength, but my understanding is that the energy density of the black hole vastly dwarfs that of the magnetic field -- and GR effects are *really* small except in really compact high energy density places.

So, TLDR: Yes, the light bends a little bit differently...a probably insignificant amount though.


We can definitely see the effects of magnetic fields and local electric fields on the light in their spectra though. (Stark effect and polarization etc.)

 

[ThatBuzzkiller]

Electric fields does not affect gravity directly ...

Gravity as we know it comes from a curved spacetime ...

 

[Biftheunderstudy]

Electric fields does not affect gravity directly ...

Gravity as we know it comes from a curved spacetime ...

That's the thing, gravity *is* curved spacetime, and an energy density curves spacetime. Therefore, energy density = curved spacetime = gravity.

Next point, electromagnetic fields have an energy density associated with them, you just square the fields (E and B) with the appropriate constants for units, so they DO have a gravitational effect associated with them. This is the whole point of the Reissner-Nordstrom solution.