ELI5: Why does light travel? Why does it not just stay in place? What causes it to move, let alone at so fast a rate?

Since this is ELI5, here is the really simple version without bringing spacetime into it.

The speed of anything is basically determined by it’s weight and the amount energy that is pushing it. You can push your toy cars really fast but if you try to push a real car it’s a lot harder. That’s because it weighs more. Light weighs nothing, so it moves at full speed all the time with no push at all.

Explain Like I`m Five: good questions, best answers.