We have names for some of the range, like visible light, X-rays, radio waves, but the really don't have names for the energy in the extreme ends. The really short wavelength stuff is just called gamma-rays. Some of this stuff is really lethal and is produced by various kinds of nuclear processes such as fusion and fission. On the other end, radio-wave energy can get extremely low. We know of no physical limit to the maximum length of radio waves except perhaps the diameter of the entire visible universe.
Objects can only produce radiation that is about as large as the object itself.
In principle, the interstellar medium between stars could produce radio waves with lengths measured in light years, but the interstellar medium would have to act coherently to do this, and this is probably not possible considering how turbulent it is. Radio waves bigger than a galaxy are probably not possible because nearby galaxies could not produce a coherent wave. In a baseball stadium, you can get people to 'wave' but they have to time themselves carefully, otherwise you can never get the wave started. Return to the Ask the Space Scientist main page.