I Just like in biology, astrophysics has its own “what came first, the chicken or the egg?” question. In this case it’s “what came first, the galaxy or the supermassive black hole?”
Because as we look at the Universe around us today we find that at the centre of every galaxy is a supermassive black hole, and what’s more is that how heavy a black hole is, is tied to how heavy its galaxy is. The two are correlated.
So we interpret that as galaxies and their black holes growing together, evolving together. If you grow one, you grow the other, along that correlation line. But if we think about what would happen if we rewound time, back to the early days of the universe when stars were just beginning to form, did the black hole form first, and then the galaxy of stars form around it?
Or did a galaxy of stars form first, one of them die and go supernova and become the central black hole? To work that out we have to look back in time, because light takes time to travel to us, as we look at more distant objects the light has taken longer to get to us and we’re seeing them as they were billions of years ago.
So the further back we look, the further we rewind time and get closer to answering that question of chicken or the egg; galaxy or black hole. Thankfully, we now have the James Webb Space Telescope, that has been designed to detect the faint light from very distant objects, and since its launch in 2021 there have been high hopes JWST would help crack this age old question...