|MadSci Network: Physics|
Ann: You will probably consider this answer very dry and not very glamorous. There is a relationship between magnetism, electricity and light. The whole set of phenomena is called electromagnetism, because they are all intertwined with each other. The major differences are that the first two can exist in static fields, whereas light is always moving at, can you guess, the speed of light (186,282 miles per second). Magnetic and electric fields can be static in time, meaning they can act like stationary fixtures, not changing in shape/size or strength, and extending through space like a fluid. Also, magnetic fields can give rise to electric fields if they are not static, that is if they are moving in position or in strength. This is also true vice-versa, electric can make magnetic fields. There are two flavors of each - positive and negative (for electrics), & north and south for magnetics. They are kind of like a beginning of the fields, and a end. Another thing to know about these fields is that they have big difference between the two, is that an electrically charged object will not react to a static magnetic field, and a magnetically charged object will not react to a static electric field. However if either is changing, then they will react as if pushed or pulled by a force. Now, light is created whenever you have a (magnetically or electrically) charged object accelerating - that is, going faster and faster or faster and slower, as long as the speed is changing. What happens is, every time the charged object accelerates, a part of the field it generates cannot catch up to the object, and is left behind. The thing is when a piece of electric or magnetic fields is left on its own, it never hangs around very long. In fact it takes off at the speed of light and rapidly disappears. That piece of a left-behind field is in fact light. Now to your question, can magnetic fields/lines contain light, the answer is no. A magnetic field does not contain light any more than a pond contains a rushing river. It is only when you accelerate the thing that makes the magnetic line that light is created, and then the light flies away very fast. Static magnetic lines (which are the things that surround our planet) do not direct light either.
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