What is Plasma?
Most of the matter with which we are familiar in everyday life exists in one of three states - solid, liquid, or gas. Plasmas, often called the fourth state of matter, are perhaps the most abundant form of matter, making up nearly 99.9 percent of the observable universe. A gas becomes a plasma when the addition of heat or other energy causes a significant number of atoms to release some or all of their electrons, a process called ionization. Thus, a plasma is an ‘ionized gas’ - a collection of electrically charged particles - that can carry electrical currents and respond to electric and magnetic fields.
Stars including the sun, the space between stars, nebulae, and the space environment near Earth are primarily composed of hot plasma. Earth’s aurora and bolts of lightning are plasmas. On Earth, plasmas are created by people every day when they turn on fluorescent light bulbs, or in laboratory experiments such as nuclear fusion devices.