[ETL]

"Normal matter — which is different from dark matter -- is composed of the particles, such as protons and electrons, that are found on the Earth, in stars, gas, and so on."

"Dark Matter" comes in two varieties: ordinary matter ("baryonic" dark matter) which simply isn't reflecting or emitting light and "non-baryonic" dark matter which is a weird theoretical form which doesn't interact with light yet still exerts a gravitational influence.

[Paradox]

There are two kinds of “stuff” in the Universe: Matter, and Doesn’t Matter. The vast majority of stuff in the universe is composed of the latter..