On a crisp September day in 1964, Roger Penrose had a visit from an old
friend. The British cosmologist Ivor Robinson was back in England from
Dallas, Texas, where he lived and worked. Whenever the two met up, they
never lacked for conversation, and their talk on this occasion was
non-stop and wide ranging. As the pair walked near Penrose’s office at
Birkbeck College in London, they paused briefly on the kerb, waiting for a
break in the traffic. The momentary halt in their stroll coincided with a
lull in conversation and they fell into silence as they crossed the road.
In that moment, Penrose’s mind drifted. It travelled 2.5 billion light
years through the vacuum of outer space to the seething mass of a whirling
quasar. He imagined how gravitational collapse was taking over, pulling an
entire galaxy in deeper and closer to the centre. Like a twirling figure
skater pulling their arms in close to their body, the mass would spin more
and more quickly as it contracted.
