Ralph Alpher, one of the key contributors to the ‘hot’ big bang theory, the revised 1948 version of Lemaitre’s l’atom primitif that led to a prediction of the cosmic microwave background, has passed away at age 86.

Dr. Alpher was awarded the 2005 National Medal of Science last month for his 1948 prediction that, if the universe started with a big bang, as others had hypothesized, it would explain the varying abundances of elements in the universe. Months later, he and two colleagues figured out that a big bang would have released an echo that should still be present in the universe as radio waves.

“It had vast implications, but unfortunately it got very little attention,” said Vera Rubin of the Department of Terrestrial Magnetism at the Carnegie Institution. “It’s a very complicated story. He and Bob Herman did something very early and very brilliant. There’s really no other word for it; they were kind of forgotten.”