What Is a Black Hole?

Black Hole 101

Explainer: What are black holes?

Gravitational pull of a black hole on a nearby star, illustrated in high detail

In honor of Black Hole Week, let’s watch an animation that depicts one way a massive star can transform into a black hole! First, a massive star evolves into a red supergiant star. Next, the envelope of the star is ejected and expands, producing a cold, red transient source surrounding the newly formed black hole. Some residual material may fall onto the black hole, as illustrated by the stream and the disk, potentially powering emission years after the collapse. Take a look at what Hubble saw b