The existence of black holes is one of the universe’s most perplexing truths. The mathematical models which describe these enigmatic celestial omnivores suggest that they are naturally, almost inevitably produced when very large stars collapse at the end of their active lives. But the models also suggest that they are places where space and time become grossly distorted, so that the heart of every hole is a singularity – the physical realisation of what astrobiologist Caleb Scharf describes in Gravity’s Engines as ‘a point at which an algebraic expression provides no meaningful answer, like calculating the value of one divided by zero’.

The literature of black holes has long obsessed over the epistemological riddle this presents for physics. Solve black holes and you might solve cosmology at the same time. This is heady, heavily theoretical stuff that is often utterly divorced from empirical evidence. But over the past few decades, we’ve begun