While space is often referred to as a vacuum, it isn't completely empty.

Most normal matter in the universe isn't found in planets, stars or galaxies – an astronomer explains where it's distributed

Source: space
Source Link: https://www.space.com/astronomy/most-normal-matter-in-the-universe-isnt-found-in-planets-stars-or-galaxies-an-astronomer-explains-where-its-distributed