How is light considered “electromagnetic” radiation, What does it have to do with electromagnetism?
In: Physics
There is an electric field and a magnetic field filling every point in the cosmos, in the same sense that water in the ocean has a height at every point on the ocean’s surface.
The electric field is responsible for attracting and repelling charged particles, while the magnetic field causes the movement of charged particles to curve. The electric field arises because charges exist, the magnetic field arises because charges move. The two are deeply related and, more properly, can be thought of as two manifestations of a single electromagnetic field.
Light, at its core, is a small “bump” in these fields where they have different values than they do in the surrounding area. In the same way that a wave in the ocean is a small area where the height of the water is different, light is a small area where the “height” (or more abstractly, value) of the electromagnetic field is different. It turns out that both waves are described by the same kind of equations, which is why we talk about light as a “wave”. Just as a water wave can travel through the ocean, electromagnetic waves travel through the electromagnetic field, and just as water waves can break on a shoreline, electromagnetic waves can hit (and interact with) objects.
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