Here's why:
* Quasars are active galactic nuclei (AGN): They are the supermassive black holes at the center of some galaxies that are actively feeding.
* Not all galaxies have active AGN: Many galaxies have supermassive black holes, but they are not actively feeding, and thus don't emit the strong radiation that makes them quasars.
Therefore, a galaxy can have:
* Zero quasars: Most galaxies don't have active AGN.
* One quasar: A galaxy can only have one supermassive black hole at its center.
* No clear upper limit: There's no set number of quasars a galaxy can have.
Instead of asking how many quasars are *in* a galaxy, we might ask:
* What percentage of galaxies have quasars? This is a more relevant question and the answer is that a relatively small percentage of galaxies have active AGN and are thus considered quasars.
* How many quasars are there in the observable universe? This is a question that astronomers are still trying to answer, but it's estimated that there are billions of quasars out there.
Let me know if you'd like to learn more about quasars or AGN!
