Here's why:

* Meteor is the term for a streak of light in the sky created by a small piece of debris from space burning up in the atmosphere.

* Meteoroid is the term for the space rock itself before it enters the atmosphere.

* Meteorite is what we call the remaining piece of a meteoroid that survives its fiery descent and reaches the Earth's surface.

So, when a meteoroid hits the Earth, it becomes a meteorite.