How to safely enter a black hole

Supermassive black holes are ideal for visiting, but 1 in 1 000, as illustrated, have dangerous accretion discs and blast jets of particles at near light speed.

- KELSO HARPER

OUR UNDERSTANDING OF BLACK HOLES has exploded in recent years, with landmark works such as the photograph of the Messier 87 galaxy's supermassive black hole and the recent discovery of a 'tiny' three-sun-mass black hole in our own galaxy. But what would it be like to make the next leap: to visit - and even enter-a black hole? We asked the experts.

First, to survive long enough to explore a black hole, you must find a big one, says Janna Levin, PhD, an astrophysicist at Barnard College of Columbia University. Black holes form when matter condenses into a tiny amount of space, like when a massive star collapses in on itself. This creates a point of infinitely strong gravity - a singularity - and a surrounding region that traps anything that wanders too close, called the event horizon.

As matter gets packed into a black hole’s central singularity, its event horizon grows. This means if you hopped into a small black hole – say, 160 km across – you’d enter relatively close to its point of infinite gravity. The change in gravity even before the event horizon would be so steep that you’d get steadily stretched from head to toe in a process irreverently called spaghettification.