Astronomy
The Nature of Quasars as Active Galactic Nuclei
Quick fact
The most distant known quasars are so bright that they outshine their entire host galaxy by a factor of 100 or more, allowing us to see them from when the universe was less than a billion years old.
Why this is interesting
When you look at a photo of the night sky, you see stars and galaxies. But some of the brightest objects in the universe are not stars at all—they are quasars, and they hold a secret that changed how we think about galaxies.