hairy black hole

A classical black hole is a bottomless well: everything that falls past the horizon disappears into a point of infinite density. But in loop quantum gravity (one approach to quantum gravity), that point is replaced by a quantum 'bounce'—a sphere of finite size where spacetime doesn't tear but rearranges itself.

Light from afar bends around a black hole like a cyclist taking a sharp turn. Get closer, and it starts looping around an invisible sphere of photons. Every black hole has such a sphere, but usually it's wobbly: the slightest nudge sends light flying away or falling in.

A black hole is not a perfect vacuum cleaner. It is surrounded by a swarm of particles and fields, and this swarm alters its fate. In a new study, astrophysicists examined how a massive vector field, a hypothetical form of dark matter, behaves near a rotating black hole.

A black hole with an electric charge is like a vacuum cleaner that not only sucks in everything around it but can also hold light particles in orbit. These particles form a kind of fuzzy cloud around the hole — physicists call it a quasi-bound state.

A black hole is like a spinning drop of viscous liquid. Normally, such a drop tends to stay whole: splitting would reduce its surface area, which contradicts the law of non-decrease of entropy (a measure of disorder, like a broken cup doesn't glue itself back together).

A black hole rings like a bell when something massive falls into it. This ring is gravitational waves, and its overtones tell us about the shape of the horizon.

A black hole isn’t a perfectly smooth ball. Einstein’s theory allows invisible 'hair' — clumps of scalar field — to swarm around it, warping spacetime. The shadow — the dark region from which light can’t escape — was predicted by Penrose in the 1960s.

A stone falls into a pond, and the ripples on the water tell for a long time where it sank. With a black hole, it would seem, things are different: everything that crosses the horizon (the boundary from beneath which not even light can escape) vanishes without a trace.

A black hole, perturbed by a merger, vibrates at characteristic resonant frequencies — much like a bell ringing after being struck. Each hole has its own spectrum of these oscillations, allowing astronomers to reconstruct its parameters.

A black hole is like a dark ball in space onto which luminous matter falls. A black hole has a shadow — a region from which rays cannot escape. But due to light bending, the shadow appears larger than the hole itself: just like a ball's shadow on a wall grows bigger when the lamp is far away.

A rotating black hole is a cosmic whirlpool that sucks in everything around it. Some of these holes have invisible threads that stretch from the event horizon like spokes from a wheel. Scientists have long debated what these threads are and whether they can be observed. In a new study, physicists have shown that these threads are not just a mathematical artifact.