The Sun's enormous heat rips electrons off the Hydrogen & Helium molecules that make up the Sun. Hence it is mostly composed of plasma.
Elements and compounds can be in various forms – solids, liquids or gases are three most common forms. These forms are known as the three common states of matter (phases of matter). There are other states of matter too, like the plasma state and a very recent discovery at ultra low temperatures known as a Bose–Einstein condensate. Plasma is a mixture of free electrons and ions. Plasma is considered as the fourth state of matter. Plasma occurs naturally in the stars (including the sun). Inside the stars, the temperature is so high that the atoms break up. Some of the electrons break away from the atoms converting the rest of atoms into electrically charged particles called ions. This mixture of free electrons and ions in a star is called plasma. The sun and other stars glow because of the presence of plasma in them.
Plasma can also be made on the earth by passing electricity through gases at very low pressures taken in a glass tube (called discharge tube). The fluorescent tubes and neon sign bulbs form plasma when they are switched on. A fluorescent tube may contain helium gas (or some other gas), and a neon sign bulb contains neon gas. When electricity is passed through a fluorescent tube (or neon sign bulb) it glows.
Picture Shows Different States Of Matter.
One may wonder that the 3 states of matter existing normally will contribute to the minor part of matter, major part of matter in the Universe is composed of plasma. Plasma contains ionized gases and can exist at temperature starting at several thousand degrees Celsius. Plasma consists of ions and electrons due to which these are electrically charged. Plasma like gas does not have definite shape or volume. Plasma self generates magnetic field and electric currents and respond strongly and collectively to electromagnetic forces.
Plasma is the most common state of matter, comprising more than 99% of the visible universe. Plasma state is characterized by a complexity that vastly exceeds that exhibited in solid, liquid and gaseous state. The study of the physical and especially the electrodynamic properties of plasma forms one of the most far ranging and intricate area in the field of research in physics. Plasma can be accelerated and starred by electromagnetic field which allows it to be controlled and applied plasma research is yielding a greater understanding of the universe. It provides many practical uses, new technologies, consumer products and also promises for abundant energy.