Preparations for the party were in full swing — but a crucial element was missing. “Your father wants to know where his costume is,” came the panicky email. “I’ve already suggested that he goes as the Planck constant,” I replied, thinking of the fun he could have with the name of the father of quantum theory, Max Planck. “Dad could just carry a plank of wood around. Job done.”
His assistant was clearly worried: “But he might knock people over if he turns around sharply. I really think it would be better to go with the underworld theme.”
The occasion was the celebration of the flyby of Pluto in July last year by the Nasa New Horizons probe; the dress code —“Come as your favourite celestial object.” The costumes were epic. There was the awesome commitment of a scientist who came dressed as the Crab Nebula, and there were partying comets, dancing cyborgs, a gas giant, the disc from the Voyager probes, the transit of Venus and Pluto the dog.
In the end, my father went as Pluto, god of the underworld. This lent a creatively spooky feel to the evening’s festivities. When darkness fell, we all trooped out into the street to watch a firework display. There, my father, dressed as the King of Hell, decided to give an impromptu speech from the pavement on the importance of exploring the solar system. Passers-by must have been surprised at being exhorted to know “no boundary to human endeavour” by a man wearing a false white beard, accompanied by a three-headed paper-mâché dog. But this being Cambridge, they took it in good part. No one called the police.
Even as the shards of leaves set alight by the fireworks fell to the ground, my father continued his oration about the need to explore and why and how that makes us human. It caused me to reflect on his total dedication to education and to communicating about scientific topics to as wide an audience as possible (even if half of them were really quite drunk).
No doubt the Reith lectures will be a more sober affair. The topic is black holes, and I don’t think my father will turn up dressed as his favourite celestial object. I expect he will be wearing a suit. But the principle is the same even if the format is more traditional — at their heart, they are lectures about exploring the universe, only instead of being about robotic spacecraft and a dwarf planet, my father will be talking about theoretical physics and collapsed massive stars, otherwise known as black holes.
Through these Reith lectures, listeners will come to appreciate the great triumph of my father’s theoretical work — his understanding of how a black hole decays through Hawking radiation. To be able to examine through mathematical calculations the nature of a black hole millions of light years away is an extraordinary achievement in its own right; to be able explain this lucidly and clearly to a non-specialist audience is quite another.
There are plenty of scientific reasons why black holes matter, but I have one other. Black holes have the ability to generate excitement among children around the study of science. They form part of the trinity of exotic phenomena — space travel, aliens and black holes — that has the power to engage kids with science.
Something about the strangeness, the distance, the scale and the possibility for adventure gives black holes the power to inspire young minds. There is even anecdotal evidence that many professional scientists working in fields different from astrophysics first became interested in science because of black holes. They may have followed other career paths, but the original inspiration was the topic of the Reith lectures: black holes.
Back in July last year no one came to that Pluto flyby party dressed as a black hole. But that doesn’t stop them from being the favourite celestial object of most children — and theoretical physicists — the world over.