Biography | Stephen Hawking — Black Holes Were Told They Were Not Black Here

People look for Hawking radiation in a Cambridge office.

The first public telling was here, at the Rutherford Laboratory on the old Harwell airfield at Chilton, on 15 and 16 February 1974.

The meeting was an Oxford symposium on quantum gravity, convened by Chris Isham, Roger Penrose and Dennis Sciama. The printed proceedings list the site as Harwell, Berkshire.

The laboratory had been the Rutherford High Energy Laboratory since 1957. The Appleton name was added only in 1979.

The campus is now the Harwell Science and Innovation Campus.

Hawking spoke on particle creation by black holes. The claim was that a black hole is not a perfect trap.

Quantum effects give it a temperature and a slow leak of particles.

A two-page letter making the same point had already gone to Nature on 17 January. It appeared on 1 March 1974 under the title Black hole explosions?

The temperature he wrote down is inverse to the mass. A solar-mass hole would take far longer than the age of the universe to vanish.

A much smaller primordial hole could end in a burst.

The room did not convert on the spot. John Taylor of King's College London chaired the session.

Later retellings, including a PBS film in which Hawking and Jane Hawking took part, remember the chair dismissing the result. The printed proceedings do not record the wording.

Nature printed a sceptical reply that July from P. C. W. Davies and J. G. Taylor.

The calculation held. The radiation now carries his name.

He was elected a Fellow of the Royal Society in 1974, the same season as the letter.

A visitor today finds a working national laboratory, not a 1974 lecture theatre kept as a shrine. The pin is the site.

The buildings have been rebuilt around it.

Photo: Rutherford Appleton Laboratory site, via Wikimedia Commons. Portrait: NASA StarChild, public domain