Albert Einstein’s theory of gravity, general relativity, is famously incomplete. As proven by physics Nobel laureate Roger Penrose, when matter collapses under its own gravitational pull, the result is a “singularity” – a point of infinite density or curvature.
At a singularity, space, time and matter are crushed and stretched into nonexistence. The laws of physics as we know them suffer a complete breakdown. If we could observe singularities, our physical theories couldn’t be used to predict the future from the past. In other words, science would become an impossibility.
Penrose also realised nature may hold a remedy for this fate – black holes. A defining feature of a black hole is its event horizon, a one-way membrane in space-time. Objects – including light – that cross the event horizon can never leave due to the black hole’s incredibly strong gravitational pull.
In all the known mathematical descriptions of black holes, singularities are present in their core. Penrose postulated that all the singularities of gravitational collapse are “clothed” by the event horizons of black holes – meaning we could never observe one. With the singularity inside the event horizon, physics in the rest of the universe is business as usual.
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