Time runs slower near a black hole
Mass bends time as well as space, so a clock hovering near a black hole's edge ticks slower than one watching from far away.
A black hole’s defining feature is its event horizon, the boundary beyond which gravity is so overwhelming that nothing, not even light, can escape. The Milky Way’s own central black hole, Sagittarius A*, weighs about four million Suns and anchors this point of no return.
But the strange physics begins before you reach it. General relativity says that massive objects warp not only space but time, and the deeper you sit in a gravitational well, the slower your clock runs compared with someone further out. The effect is real and measurable even on Earth: clocks on aircraft tick fractionally faster than identical ones on the ground.
Near a black hole it becomes extreme. To a distant observer, an object falling toward the horizon appears to slow down and freeze, its light stretched and dimmed, never quite seen to cross. The falling object, meanwhile, notices nothing odd about its own time.
Time, it turns out, is not a fixed backdrop but something gravity quietly bends.
Sources & references
2 referencesWell-established. Corroborated by 2 independent sources.
