NGC 3842:(It is around 331 million light-years distant from Earth.)
At first glance, NGC 3842 seems like a rather unassuming elliptical galaxy. True, it is the brightest galaxy in the Leo cluster, but other than that, it doesn’t seem to be too notable. However, a detailed analysis revealed that this galaxy is hiding something that is truly monstrous.
The black hole at the center of this galaxy is an amazing 9.7 billion solar masses. Saying that it’s “big” is a bit like saying that the Sun is “warm”—it’s an astronomical understatement. Really, it is. Think about it for a moment. That black hole has eaten 9.7 billion Sun-sized stars (or objects of comparative mass). Unsurprisingly, such an amazingly huge object is hard to fathom. Fortunately, there are a plethora of comparisons. For starters, the “point of no return” or event horizon (where the gravitational pull is so great that nothing, not even light, can escape) is five times greater than the orbit of Pluto. This means that the event horizon would extend well beyond the edge of our solar system; our little neighborhood would be swallowed 5 times over. Ultimately, this monster could have consumed entire civilizations—many, many civilizations, in fact.
And the gravitational influence of the black hole would extend over a sphere 4,000 light-years across. Just how far is that? For comparison, The Small Magellanic Cloud (a dwarf galaxy near the Milky Way) has a diameter of some 7,000 light-years and contains several hundred million stars…which is nowhere near 3284’s 9.7 billion solar masses. So this black hole puts an entire galaxy to shame (…a dwarf galaxy, but still).