# Can a light be bent by a magnetic field?

I'm struck with two competing ideas on the question in the title.

• How far can a magnetic field bend light?

A: Unfortunately, the path light takes is not affected by the presence of a magnetic field. Light itself is composed of an oscillating electric and magnetic field, and one very important property of electric and magnetic fields is what we call linearity. That is, if you have two sources of electric and/or magnetic fields, you can predict what the combined field is just by adding the two source fields together. The two fields don’t change each other at all.

Listing #2 (Answer #1) Does electric charge affect space time fabric?

• Does electric charge affect the space time fabric? If so, why?

I'm more inclined to consider the latter question and answer as the correct interpretation. Anyway, if anyone could help me out with this conceptualization that would be great, thanks.

-
What exactly are you asking? It's not clear the way the question is written. – David Z Jun 9 '13 at 3:45
I think by "ladder" you meant "latter" - anyway I edited it for you – twistor59 Jun 9 '13 at 6:29
@twistor59 thanks, I was shorted by the "ladder operators " :) – anna v Jun 9 '13 at 6:59
classically, probably never (by superposition principle); but quantum physically(i.o.w. the real world), I have no idea. – Shing Dec 25 '15 at 9:54

The first link you give the questioner wants to use magnetic fields to turn light in a circle, and is answered correctly .

You are asking about bending. In both of your links the answer exists that the magnetic field with its energy will contribute to the gravitational field about the source of the magnetic field and and might contribute to the observed gravitational lensing, and in that sense the magnetic field will contribute to the bending of light in gravitational lensing.

Think of geodesics. Light follows geodesics, straight if the gravitational sources are very small. The geodesic bends where the gravitational sources are strong ( gravitational lensing) . A strong magnetic field will contribute with its energy to the mass creating the geodesic, and that is all. The effect is very weak because the gravitational "interaction" is very weak with respect to the electromagnetic.

If you were thinking of the single photons comprising light then you have to go to the particle interactions and exchanges, where the rules follow quantum electrodynamics. In this frame the magnetic field will interact with a photon through higher order diagrams,( which means low probability).Photons can be scattered from virtual photons of the magnetic field , and change direction, which can be considered a bent ;if the beam photons have enough energy ( gamma rays) pair creation can appear.

Because these interactions are on individual photons, with low probability, the beam direction which depends on a huge ensemble of photons that comprise it will not change. It will just lose a few photons randomly in direction .

-

Light changes direction when there is a switch in the medium through which it travels. For example, from air to water. Probably it is the density of the medium which matters. This is why you see waving images when looking over a hot car on a sunny day. If so, if one would create a sequence of progressively denser mediums, he could divert it considerably from its original trajectory.

Creating such sequence is a challenge. A sandwich of air streams of different temperatures? A sandwich of gases of different weights?

-

First, the electromagnetic frequency spectrum, (EFS) is just a definition. It represents the change in intensity of the electric field and the magnetic field and they are defined as being at right angles to each other. The frequency is defined as the inverse of the average time from one null to the next or one peak to the next peak in field intensity.

Don’t confuse the properties of light with the properties of light’s interaction with the medium in which it is traveling.

If light had a magnetic property, it would be affected by a magnetic field in a pseudo vacuum. It isn’t.

If light had an electric property, it would be affected by an electric field in a pseudo vacuum. It isn’t.

Light, in fact, is a particle of energy that scientists have called a photon.

The “frequency” property of light is set by the distance between the photons that are emitted in a linear path to the detector, the eye. When the photon strikes the detector (eye), it is believed that its energy releases an electrical charge that the brain can sense and ultimately give an image if enough photons are received.

Light is in fact no more a part of the EFS than sound is.

Sound can be an acceptable analogue for light, where sound is the externala mechanical moving of existing medium particles and light is the generation of particles. Sound has two frequency components when viewed in a singular linear path. First is the spacing of the medium particles (which has a large swing in frequency/period when reaching the detector (ear)). It would be interesting to see if this frequency had any affect on the ear. Second is the spacing of the “pressure’ peaks or nulls. This is what the ear senses and the brain converts.

Keep in mind that the classic right angle sine wave representation of the EFS is just a representation and doesn’t actually exist. It is just to help us understand the properties we can observe. Unconfined light and sound emanations are spherical in nature.

It’s a shame that our science community refuses to admit they were wrong in claiming light was a part of the EFS.

-
Frequency is not the distance between emitted photons. A single photon has a frequency defined by $E=h\nu$, which is independent of the distance between it and any other photon. A photon is a propagating perturbation in the background EM field where the strength of the fields oscillate at the given photon's frequency. As a perturbation, it is not affected by the value of the background field. It is, by all definitions, a wave through the background EM field, and as such, it is what makes up the EM frequency spectrum – Jim Dec 21 '14 at 20:56