Nearest: Quasar

While often cited as the nearest "true" quasar, a note on terminology: Some very low-activity galactic nuclei (like the one in Andromeda) are not quasars. And an object called is sometimes mistakenly called "nearest" — but 3C 273 is about 2.4 billion light-years away. Mrk 231 is genuinely the closest object that displays the full, powerful quasar phenomenon.

| Object | Type | Distance | Notes | |--------|------|----------|-------| | | Quasar | 581 million ly | True quasar; hosts powerful, persistent accretion disk & outflows | | 3C 273 | Quasar | 2.4 billion ly | Brighter and more famous, but not nearest | | Sagittarius A * | Supermassive black hole | 26,000 ly | Our galaxy's center; not a quasar (extremely low luminosity today) | | Centaurus A | Radio galaxy / AGN | 10–16 million ly | Nearest powerful AGN, but not a quasar (jet-dominated, nucleus obscured) | nearest quasar

Markarian 231 is not just a typical quasar; it is an that is currently undergoing a violent merger process. While often cited as the nearest "true" quasar,

: Despite its distance, it is one of the most energetic objects in our local universe. Quasars like this can outshine their entire host galaxy, emitting light across the entire electromagnetic spectrum. Why the "Nearest Quasar" Matters | Object | Type | Distance | Notes