Atoms, the building blocks of matter, are constantly in motion, moving around at speeds that are thousands of miles per hour at room temperatures, and millions of miles per hour behind a supernova shock wave.
In a collision of an atom with another atom, or with a free-roaming electron, energy can be transferred to the atom. This extra energy can then be released in the form a light wave.
Here, there, and everywhere that atoms and electrons collide at high speeds, for example, in neon signs, in auroras, or in supernova shock waves.
"Here, There, & Everywhere" (HTE) is supported by the National Aeronautics and Space Administration under grant NNX11AH28G issued through the Science Mission Directorate.