Shahar Hod

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.

An engineering blueprint of a skyscraper always includes a number: the maximum load on the foundation — say, 500 kilopascals. Einstein's field equations in curved spacetime impose a similar limit on the 'force load' inside stars, planets, and any other clumps of matter.