Mass in special relativity what causes these particles to be termed "massless." However, even massless particles have a relativistic mass, which varies with their observed energy in various frames of reference, The invariant mass is the ratio of four-momentum (the four-dimensional generalization of classical momentum) to four-velocity: and is also the ratio of four-acceleration to four-force when the rest mass is constant. The four-dimensional form of Newton's second law is: The relativistic expressions for "E" and "p" obey the relativistic energy–momentum relation: where the m is the rest mass, or the invariant mass for systems, and "E" is the total energy. The equation is
C. N. Yang Institute for Theoretical Physics most notably was the discovery of Supergravity in 1976 by Peter van Nieuwenhuizen, Daniel Z. Freedman, and Sergio Ferrara, who were all working there at the time. C. N. Yang Institute for Theoretical Physics The C. N. Yang Institute of Theoretical Physics (YITP) is a research center at Stony Brook University. In 1965, it was the vision of then University President J.S. Toll and Physics Department chair T.A. Pond to create an institute for theoretical physics and invite the famous physicist Chen Ning Yang from Institute for Advanced Study to serve as its director with the Albert Einstein Professorship of