Sunyaev is a pioneer in the fields of X-ray astronomy and the cosmic background radiation, and in 1972, working with Yakov Zel’dovich, he predicted that the cosmic background would be cooled as it passes through hot gas. This effect, now known as the Sunyaev-Zel’dovich effect, is widely used in astrophysics and cosmology to determine absolute distances.

Previous winners of the Gruber prize include Jim Peebles and Allan Sandage (2000), Martin Rees (2001) and Vera Rubin (2002).