[TheDudeMan]

"Sagittarius A has the combined mass of several million suns. It lurks at the heart of the galaxy and formed not from an exploding star but the collapse of vast clouds of dust and gas."

How is that known? Isn't "dust and gas" also how stars form?

[alje]

Every galaxy we know of contains a massive black hole in the center. Until recently, the widely held belief was that massive black holes are formed via the process of mearging smaller black holes in large timeframes. However, once the JWST came online, astrophysicists discovered early massive black holes close to big bang that could not be explained by that cumulative process. There just was no time for the cumulative creation to a such large black holes.

So the current working hypothesis for massive black holes in galaxies is that they formed directly from the gravitational collapse of "vast clouds of gas and dust" with such high gravitational pressure that the core couldn't keep up, and the entire mass of gas and dust collapsed into a massive black hole. There is no supernova involvement; merely a direct transition into a black hole.

Of course, take my laic simplification into account.

[kubanczyk]

A vast cloud of what gas and what dust? I thought we had started with only hydrogen and I thought that collapsing the hydrogen creates stars first. How could it even cut directly to the stage of black hole?