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.
Some of the common causes of Charlieâs Horses in legs are: 1  Mineral deficiency: Low levels of mineral such as potassium and calcium may lead to cramping. 2  Low levels of body fluids while doing strenuous exercise may lead to Charlie Horses. 3  Hormonal imbalance is also a cause for Charlie Horses.