From B. S. Chandrasekhar
Wesson has to go to the fifth dimension to look for negative mass. Or, more easily, he can look up an article in the American Journal of Physics (vol 63, p 853) in which I show that the well-known object called a hole in condensed matter, which represents an energy band with one missing electron but otherwise full, has negative mass – m, where m is the electron mass.
Groebenzell, Germany
