"US physicist John Wheeler, one of Albert Einstaein's last collaborators who helped build the atomic bomb and gave black holes their name, died at the weekend," his family said. He was 96.
President George W. Bush issued a statement on Monday saying that he and First Lady Laura Bush "are saddened by the death of ... one of America's greatest physicists."
"During his distinguished career," Bush added, "Dr. Wheeler collaborated with scientists such as Albert Einstein and Niels Bohr on projects that changed the course of history."
"Wheeler, who was involved with the Manhattan project that build the world's first atomic bomb, died April 13 of pneumonia at his home in Hightstown, New Jersey, said his daughter," Alison Wheeler Lahnston.
Born July 9, 1911 in Jacksonville, Florida, Wheeler tried unsuccessfully to complete Einstein's unified theory after his death.
He also helped work out the Harrison-Wheeler equation describing high-density nuclear matter that occurs in the heart of neutron stars.
He coined the term "black hole" for stars that collapse into such dense cores that light cannot escape from them.
During a conference on the subject in New York in 1967, a student shouted "black hole" to suggest a name for the phenomenon. Wheeler made the name a household word.
Wheeler became a professor at Princeton University in New Jersey in the 1930s, and remained on the faculty at the prestigious university all his academic life before moving to the University of Texas in 1976, when he was close to retirement.
Massachusetts Institute of Technology cosmologist Max Tegmark told The New York Times that Wheeler was "the last Titan, the only physics superhero still standing."