Cathode rays exist in the form of streams of high speed electrons emitted from the heating of cathode inside a vacuum tube at its rear end. When the cathode is heated, it emits some radiation which travels to the anode. If the inner glass walls behind the anode are coated with a phosphorescent material, they glow. Cathode rays are streams of electrons observed in vacuum tubes, i.e. evacuated glass tubes that are equipped with at least two electrodes, a cathode (negative electrode) and an anode (positive electrode) in a configuration known as a diode. It is likely that technologies such as plasma displays, liquid crystal displays, and other newer technologies will eventually make CRT-based displays mostly obsolete, because the new designs are less bulky and consume less power.The electromagnetic fields emitted by CRT monitors constitute a health danger to the functioning of living cells.