In 1951–53, Ruderman worked at Berkeley's
Radiation Laboratory. He became an assistant professor at UC Berkeley in 1953, rising by 1964 to the rank of full professor. He moved to
New York University in 1964, and to Columbia University in 1969, becoming Centennial Professor in 1980. Ruderman served as chair of the Department of Physics at Columbia in 1973–75. In 1969, Ruderman and (independently)
Gordon Baym,
Christopher Pethick, and
David Pines, were the first to propose that discontinuous slowings observed in
neutron stars, so called
starquakes, were due to the cracking of the star's solid crust, under increasing stress due to the gradual slowdown of the
pulsar. Ruderman died on July 20, 2024, at the age of 97. ==Honors==