On the Fellowship of Roy Kerr

Among the new Fellows of the Royal Society announced this week, I was astonished to see the name of Roy Kerr, the man who gave his name to the Kerr Metric an exact solution of Einstein’s equations of general relativity which describes the geometry of space-time around a rotating black hole.

When I say “astonished” I don’t mean that Kerr does not deserve this recognition. Far from it. I’m astonished because it has taken so long:the Kerr solution was published way back in 1963.

Anyway, better late than never, and heartiest congratulations to him!

While I’m on about Roy Kerr I’ll also say that I now think there is a very strong case for him to be awarded a Nobel Prize. The reasons are twofold.

One is that all the black hole binary systems whose coalescences produced gravitational waves detected by LIGO have involved Kerr black holes. Without Kerr’s work it would not have been possible to construct the template waveforms needed to extract signals from the LIGO data.

Second, and even more topically, the black hole in M87 recently imaged (above) by the Event Horizon Telescope is also described by the Kerr geometry. Without Kerr’s work the modelling of light paths around this object would not have been possible either.


4 Responses to “On the Fellowship of Roy Kerr”

  1. Shantanu Says:

    Peter do you know if EHT rules out alternatives such as gravastars, or dark energy stars or exotic boson stars?

  2. Anton Garrett Says:

    Well said. It didn’t take Rutherford so long.

  3. Davide Castelvecchi Says:

    Is the EHT observation incompatible with a Schwarzschild black hole? My understanding was that they could not show conclusively that it was spinning.

    • telescoper Says:

      Probably not ‘incompatible’ with Schwarzschild but my understanding is that the best fitting model for all the M87 observations is a black hole that is rotating with a rotational axis that points away from Earth at about 17 degrees.

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