If you’re looking for irony, it doesn’t get much more ironic than black holes.
The densest objects in the Universe, their gravitational force is so fierce that anything that gets too close is gone. Over the event horizon and out of reach. Bloop. Down you go. Bye bye.
This makes them the darkest possible objects there can be. Not even light can escape them.
However, material that falls toward them may not fall straight in. It can spiral around and form a disk of matter. Stuff close to the black hole moves incredibly fast around it while stuff farther out is moving more slowly. That means there’s a lot of rubbing, a lot of friction. The material heats up. Matter that gets hot glows, and around some black holes there’s so much matter that’s so hot it glows incredibly brightly, bright enough to outshine entire galaxies!
That light is coming from just outside the black hole’s point of no return, so no laws of physics are being broken. But it does illuminate the irony: The darkest objects in the Universe power the brightest objects in the Universe.
Binary system illustration containing a stellar-mass black hole. The strong gravity of the ...