The physicist who coined the term black hole to describe the densest phenomenon in the cosmos has passed away at age 96. John Archibald Wheeler worked with some of the most important figures in the history of science and eventually became, himself, one of the towering giants of 20th-century physics.
According to an online account from the Associated Press earlier today, Wheeler succumbed to pneumonia Sunday at his home in Hightstown, N.J., not far from Princeton University, where he served as a professor of physics from 1938 to 1976, alongside some of the world's most renowned theoreticians.
Wheeler received his Ph.D. in physics from Johns Hopkins University in 1933 for his research into the properties of helium. In 1937, after a year of study in Denmark under the tutelage of Niels Bohr, he formulated the scattering-matrix, which relates the initial state and the final state for an interaction of particles. Also called the S-matrix, Wheeler's formula became a fundamental tool in the field of quantum physics.
His understanding of the basic forces at work at the subatomic level led Wheeler to join a growing cadre of advanced physicists in the late 1930s who believed that a sufficiently large fission event could produce a chain reaction capable of great destruction. When war broke out in Europe in 1939, Bohr relocated to the United States and joined Wheeler to work on a model of nuclear fission.
When hostilities escalated into World War II, Wheeler suspended his academic career to participate in the American atomic bomb endeavor, the Manhattan Project, offering key insights into the physics involved. Afterwards, he volunteered to work on the next-generation nuclear weapon, the hydrogen bomb in the late 1940s.
With his government research finished, Wheeler returned to Princeton, where he collaborated with Albert Einstein in the waning years of his life on a unified field theory of the physical forces of nature. Continuing in this elusive pursuit after Einstein's death, Wheeler described a theoretical curiosity he called a "wormhole" that should exist in nature if the principles of relativity were correct. This same research led him to posit, in 1967, that extremely large masses throughout the universe could collapse under the force of their own gravity to form what he termed a "black hole."
Further pursuit of the role of gravity in a Grand Unified Theory of physics led to his collaboration with Bryce DeWitt on the Wheeler-DeWitt equation, which he later described as the "wave function of the Universe."
Later in life, Wheeler became a champion of a form of cosmological anthropism, which states that humans should take into account the constraints that human existence as observers impose on the sort of universe that can be observed. His version of this line of thinking is known as the Participatory Anthropic Principle.
Recently, he stated: "We are participators in bringing into being not only the near and here but the far away and long ago. We are in this sense, participators in bringing about something of the universe in the distant past and if we have one explanation for what's happening in the distant past why should we need more?"
Throughout his career at Princeton and later the University of Texas, where he served out his last years in academia before retirement, Wheeler was known for the enthusiasm he exhibited for education. Even after he had achieved fame, he continued to teach freshman physics, telling protégés such as Richard Feynman, that young minds were the most important to inspire.
He inspired many.
