One contender for the smallest thing in the universe is the singularity at the center of a black hole. (Shown here, an artist's drawing of a black hole pulling gas away from a companion star.) NASA E/PO, Sonoma State University, Aurore Simonnet Black holes are the only objects in the universe that can trap light by sheer gravitational force.

Scientists believe they are formed when the corpse of a massive star collapses in on itself, becoming so dense that it warps the fabric of space and time.

And any matter that crosses their event horizons, also known as the point of no return, spirals helplessly toward an unknown fate.

Despite decades of research, these monstrous cosmological phenomena remain shrouded in mystery.

They're still blowing the minds of scientists who study them. Here are ten reasons why:

Randy Astaiza contributed to an earlier version of this post.