This is a bit of a trick question! There are many states of matter, but the only one that isn't found on Earth is plasma.

Here's why:

* Solid, Liquid, Gas: These are the states we experience most often on Earth.

* Plasma: This is sometimes called the "fourth state of matter." It's an ionized gas where electrons are stripped from atoms, creating a superheated, electrically charged state. While rare on Earth, plasma is actually the most common state of matter in the universe (think of stars!).

Let me know if you'd like to know more about plasma!