Brandon Carter

Brandon Carter, born in 1942, is an Australian theoretical physicist who studied alongside Hawking under Dennis Sciama at Cambridge and went on to make several contributions that intersect directly with Hawking's work.

His own work

Carter is known for two quite different ideas. The first is technical: he did foundational work on the properties of rotating black holes and on the no-hair theorem, the result that black holes are described by just a few numbers. The second reached far beyond physics: Carter coined the term "anthropic principle," the observation that the properties of the universe we observe must be compatible with our own existence as observers, since otherwise we would not be here to measure them. The anthropic principle has been debated by physicists and philosophers ever since.

His connection to Hawking

Carter's most direct link to Hawking is the four laws of black hole mechanics, set out in a celebrated 1973 paper by James Bardeen, Brandon Carter and Stephen Hawking. These four laws mirror the laws of thermodynamics with uncanny precision, and they are the formal foundation of black hole thermodynamics. At the time, the parallel with thermodynamics was treated cautiously, almost as an analogy. It was Hawking's later discovery of Hawking radiation that revealed the laws to be literally, physically true. The anthropic reasoning Carter pioneered also resurfaced in Hawking's later cosmology, including in The Grand Design.