The reigning model of cosmology (the history of the universe) holds that it formed as a cooling bubble in a super-heated stew. It proposes that a lot of energy was stored in the fabric of space (whatever that means), and what we recognize as matter was created as that energy was released. That matter slowly coalesced to form concentrated seeds that eventually grew into galaxies. It’s a model not too different from the model we have for the formation of the solar system.
The model is notoriously called the “Big Bang” theory, but it’s not really a bang, nor is the universe really big in absolute terms. In fact, in that super-heated stew our universe is just a little tiny bubble that only looks big to us because as energy is released from the fabric of space signals travel more slowly through it, much as a violin string vibrates more slowly when it is loosened. In my book Love Works I coin another term for the process: the “Expansive Cool.”
The problem is that this model of gradual accretion is very difficult to reconcile with the structure and sub-structure of the universe. This was first apparent in the distribution of galaxies, which is non-uniform. A more recent study of the age of stars in the Milky Way also shows some surprising structure.
It will be interesting to see if the cosmologists can come up with an explanation. I have to hand it to the astronomers, though: they sure know how to use pretty pictures to make a point!