Space · Light around a black hole
How does a black hole bend light?
What you’ll see
Light travels in straight lines. But mass curves space itself, so near a black hole, every line bends. Far away, a ray turns only slightly. Aim it closer, and it turns more, and more. At one and a half times the hole's radius, light can circle it forever. Any closer, and it falls in. Now send light in from every side. Every ray aimed closer than two point six radii is swallowed. So the shadow we see is two point six times wider than the hole itself. And a star right behind it doesn't vanish. Its light bends around every side at once, into a ring.
