Scientists generally believe that the universe is made up of neither pure gas nor pure plasma, but rather a combination of different states of matter. Gas is characterized by particles having high kinetic energy and being relatively far apart from each other, while plasma is a hot, ionized gas often characterized by the separation of electrons from their parent atoms. The universe contains a variety of objects and structures that exhibit different combinations and characteristics of gas and plasma, including stars, planets, galaxies, and interstellar gas clouds.