Why does light even move? what force makes it move at insane speed?
In: 193
Instead of thinking of it as movement, think of light spreading.
When you drop water on the floor, it “moves” at a speed consistent with the angle, mass, etc. But light doesn’t have those resisted factors like friction or air resistance..
So it spreads at an incredible speed.
If it doesn’t move that fast, it wouldn’t be called light. Light is actually part of something bigger that can move at various speeds (and can even decay very quickly). The component that move fastest is called light. You just don’t see the other components normally, because if it moves slower it has mass, and when it has mass it decay in strength, and in fact it decays so much that its range of movement is effectively less than the size of a proton.
You’ve got a lot of answers to the light-specific part of the question, but a comment on the second part of the question:
Movement doesn’t require force. Only a *change* in movement requires force.
You’re used to associating movement with force because we live an environment that always has things slowing us down. If you’re moving along the ground, you have friction. If you are moving through the air, you have air resistance. So you need a constant force pushing you forward, in order to cancel the forces slowing you down.
If you’re out in empty space and you are flying along, you don’t have or need any force to keep moving.
There are lots of “fast” things that aren’t light, e.g. solar neutrinos that have mass, but move at *nearly* (not quite) light-speed (by our reference frame). They don’t need an active or ongoing “force” to keep moving. They just do that forever until they hit something.
A light analogy that keeps my brain happy is imagining a table of billiard balls all touching one another. An impulse one side causes an almost instantaneous reaction the other – the time between the cause and effect being a function of the physical characteristics of the medium and being a constant
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