These studies have shed light on the structure of magnetic fields in star-forming regions and the flow of gas from newly formed stars. Observing several maser lines at the same time has proved to be a powerful way of studying the atmospheres of red giants and showing gas clouds accelerating away from the surface. How radio waves are made Objects emit radio waves because of their temperature. The hotter the object, the more radio waves it emits. This is known as thermal emission and is a very common source of radio waves in the universe.
Thermal emission comes from gas clouds stars and planets.
Sometimes high-speed electrons are whirled around by magnetic fields in space. They radiate away their kinetic energy as radio waves, a process known as non-thermal emission. This process is a powerful source of radio waves in many types of astronomical object, including supernova remnants, pulsars, the Milky Way, radio galaxies and quasars. It is most important at longer wavelengths. An astronomical sources may generate radio waves over a broad band wavelengths.