Hints:

supermassive

NGC

20-30

Hubble

Nukers

the Milky Way

In every galaxy scientists looked at, they found evidence for a supermassive black hole.
NGC 3115
NGC 3377
NGC 3379
In M31 and M32
In total there is probably 20-30 or so black holes that have been found.
Supermassive black holes were supposed to be rare, but Hubble was finding them everywhere, both feeding in active galaxies and lurking quietly in ordinary galaxies.
Pretty soon we got used to the idea that everything we would look at would have a black hole in it. You know, after the first three or four cases, we are beginning to wonder: does every one have a black hole?
One by one we were seeing this picture sort of emerge out of the fog that, that every galaxy, almost every galaxy had a supermassive black hole in it. It was really quite astonishing.
Far from being rare freaks of nature, the Nukers began to suspect that all galaxies could have giant black holes at their hearts. If this was true, it would revolutionize ideas of what a galaxy actually is. More disturbingly, it meant there could be a supermassive black hole lurking at the heart of our very own galaxy, the Milky Way.

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