Cloudscape

Self-replicating spacecraft could replicate until there were many enough to build even greater self-replicating spacecraft, which could then in turn replicate to build even greater spacecraft, so that through self-replicating spacecraft one could eventually create megastructures which could manipulate the solar system in any way theoretically possible. In this, these self-replicating spacecraft would be similar to self-replicating nanomachines, which could build even smaller self-replicating nanomachines and so on, so that nanomachines could eventually manipulate molecules in any theoretically possible way.

Galaxies may have arisen in a way similar to that in which solar systems arose. Suppose that a very heavy star would explode in a gamma ray burst, then its core would presumably have collapsed into a black hole; this black hole could later have grown to the giant in the center of the Milky Way’s active galactic nucleus, for example. If such giant star would have spun before its explosion, this could in part explain why galaxies are usually oblate, although galactic tidal forces would also play a role in its oval shape, especially when galaxies actually collide.
The stellar nebula which would have formed upon this gamma ray burst would become an immense star nursery, from which eventually the first stars of the galaxy would form. And just like the planets which formed from the protoplanetary disc orbited their star, the stars which would form from this protostellar disc would orbit their black hole. Later, this black hole would form the center of the active galactic nucleus of the galaxy. This would also be the cause of quasars, which then may or may not cool down to later become active galactic nuclei (quasars themselves are far too energetic to be AGNs, able to produce up to 100 times more energy than the entire Milky Way galaxy, that is to say, ~1038 watts).
Later, the galaxy would gradually accrue as it would continually capture migrant stars from other, smaller galaxies interacting with it. These, in turn, would also have arisen in similar processes, feeding on even smaller galaxies, which would in turn have fed on even smaller galaxies, and so on until the first galaxies were formed from stars wandering in intergalactic space.
Eventually, like the planets formed from planetesimals, galaxies formed from galaxisimals; and like the planets had cleaned their orbits from planetesimals, the galaxies would have cleaned their paths from galaxisimals.
If this is true, then the most destructive forces in the universe are also the most creative. The feared phenomena of black holes and gamma ray bursts could actually lie at the root of our own existence.
It is possible that this evolution is even happens even today, although it happens far too slowly to be observed. Gamma ray bursts are registered in our telescopes once a day, and the energy released in them is gigantic - on the order of 1047 joules - a thousand times more than in a supernova and ten times more than in a hypernova. As the sun, as an average star, has a power of 3,827 · 1026 J, and there are 400 billion stars in the galaxy, the Milky Way’s stars together have a total power of 1036 watts, so that it takes the galaxy‘s stars a hundred billion seconds - or three thousand years - to produce as much energy as a gamma ray burst: supernovas happen only once every fifty years in the Milky Way.
If galaxies may arise in this way could be corroborated easily: the farther away an object is, the older its light is, so that the farther one looks forward in space, the farther one looks backward in time. So to say, distance in space equals distance in time by the speed of light (s=t/c). (That’s why quasars are all billions of light years away. It might also be why most gamma ray bursts are billions of light years away, so we probably don’t need to worry about gamma ray bursts occurring anywhere near us.)
So the farther a cluster of galaxy is, the greater the frequency of interactions between those. This increase of frequency with distance, and therefore time, could be extrapolated back into time perhaps billions of years, so that one would arrive back at the time where galaxies were born. If small galaxies are found to interact with remnants of very large stars, this would also indicate that these may lie at the origins of galaxies.
In conclusion, the evolution of a galaxy would basically look roughly like this:

Red hypergiant
→ gamma ray burst / hypernova
→ black hole + stellar nebula
→ black hole + star nursery
→ quasar
→ active galactic nucleus
→ galaxisimal
→ galaxy