Since the distance between the Zeeman sub-levels is a function of the magnetic field, this effect can be used to measure the magnetic field, e.g. that of the Sun and other stars or in laboratory plasmas.
Charley horse: Slang for a cramp in a muscle in the leg, usually caused by a strain or injury. A charley horse can last anywhere from a few seconds to over a quarter of an hour. It is not uncommon for one to recur before it finally resolves.
1 Low levels of minerals, such as sodium, magnesium or potassium, in the body can be one of the reasons for Charlie horses. 2  Deficiency of calcium in pregnant women can also be another reason for the onset of Charley horse. 3  Low level of liquids in the body, while exercising, might be a probable cause of Charley horse.