A solid, glowing-hot object will emit light over the full range of wavelengths resulting in a spectrum. If a diffuse and relatively cool cloud of gas is located between the glowing, hot object and an observer, the observer will detect an spectrum coming out of the cloud. Another type of spectrum is given off by a neon sign which is a tube of gas whose electrons are excited by an electric current. The mostly red light given off by the sign is in the form of an spectrum.