A black hole is born

The event horizon

The collapsed center shrinks without end and becomes a black hole. The boundary that not even light can escape is called the event horizon. For a black hole of 15 Suns, this boundary is about 89 km across. Starlight coming from behind the black hole bends around it and looks like a ring.

Why?When gravity is very strong, even the path of light bends. The black hole itself is dark, but light from stars behind it curves around the edge and shows up as a bright ring.

Learn moreThe horizon size comes from a formula in which it grows in step with the mass (using the speed of light and the gravitational constant). The 15-Sun mass is just an example; the real value depends on how much mass the star lost. How a black hole bends time and space continues in the series film “Secrets of Spacetime and Black Holes.”

When

About 5 million years old

Star we are watching

Black hole

Size · state

Horizon about 89 km across (example: 15 Suns)