The Golden Age of Black Hole Physics


The 10 year period from Roy Kerr's discovery of the rotating black hole solution in 1963 until Stephen Hawking's discovery of black hole evaporation in December 1973 represents a Golden Age of Black Hole Physics. The timeline below (adapted from The Free Dictionary site with black hole pre-history prior to GR neglected) dramatically illustrates why.

Although black holes were a theoretical possibility ever since Karl Schwarzschild discovered the non-rotating solution in 1916, and considered by many to be a strong physical possibility following Robert Oppenheimer and Hartland Snyder's work in 1939, until 1963 there remained a strong school of opposition to the idea. In particular, there were those who believed that perturbations - and, in particular, those perturbations caused by rotation - would stop black hole horizons ever forming. Roy Kerr's dramatic discovery showed that this was not the case, and since rotating solutions with event horizons existed, black holes had to be taken very seriously as actual physical objects of the universe.

As with many major leaps in science, acceptance of the reality of astrophysical black holes was not immediate. It is ironic that the first observations of then mysterious quasars were discussed at the very same Texas symposium in 1963 where Roy first presented his results to a generally unreceptive audience. As the Kerr solution was explored further it came to be realised that supermassive Kerr black holes can explain the engines that power quasars, and also the gamma ray bursts resulting from the most violent supernovae.

The timeline of black hole physics

Note: The time line uses modern terminology. The term "black hole" was coined by John Wheeler [1], being first used in his public lecture "Our Universe: the Known and Unknown" on 29 December, 1967. The terminology that "black holes have no hair" in respect of various uniqueness and "no hair" results, was also due to John Wheeler and was introduced in an article co-authored with Remo Ruffini in 1971 [2].

At the beginning of the Golden Age of Black Hole Physics, black holes were referred to as "frozen stars" or "gravitationally collapsed objects". The change in terminology in the late 1960s deeply reflects the paradigm shift that the discovery of the Kerr solution unleashed. It was realised over time that black holes not only do exist, but are far from being dead boring objects; they are highly dynamical. We now understand that they are very important to the formation of galaxies, and are a central feature of the life of the Universe.

References

  1. J.A. Wheeler's lecture appeared in the Phi Beta Kappa Society journal The American Scholar (Vol. 37, no 2, Spring 1968); and in the Sigma Xi Society journal American Scientist, (Vol 56, no 1, Spring 1968, pp 1-20). The announcement page is reprinted in V.P. Frolov and I.D. Novikov, Black Hole Physics: Basic Concepts and New Developments, (Kluwer, Dordrecht, 1998), p. 5.
  2. R. Ruffini and J.A. Wheeler, Physics Today 24, 30 (1971).