05-Hubble's Final Frontier 哈勃的最终领域

During the blast of a supernova, the inner core of a star collapses into a single point. Smaller than a pinhead.

Astronomers call this single point, a "singularity".

A singularity is an object with no length, width or height. Yet it retains most of the gravity of the original star.

One of the primary goals for Hubble was to prove once and for all whether or not black holes exist.

But how does one search for an invisible point?

Astronomers decide to direct Hubble to examine the exact centers of galaxies It is a wise decision.

What they discover is that the stars close to the center of galaxies zoom around at very high speeds.

This is not how stars normally behave. Most stars move along at relatively slow speeds.

But down in the central hub of galaxies stars are being thrown around by the gravity of something that is massive, yet ultra compact.

There can only be one cause for this effect. The fabled black hole.