Question: why do we have meteor showers?

Thomas Barrett answered on 9 Mar 2015:

A meteor is a space rock—or meteoroid—that enters Earth’s atmosphere. As the space rock falls toward Earth, the resistance—or drag—of the air on the rock makes it extremely hot. What we see is a “shooting star.” That bright streak is not actually the rock, but rather the glowing hot air as the hot rock zips through the atmosphere.

When Earth encounters many meteoroids at once, we call it a meteor shower.

We get these as space has lots of rocks floating around in it that are far too small to be called planets. Every so often their orbit crosses ours and they burn up in the atmosphere.