Current cosmology features a ‘standard model’ of the universe, starting at the singularity known as the Big Bang and describing the evolution of the universe from that point to present.
Observation has produced some problems with the standard model, however.
The cosmic background microwave radiation map is too uniform to match theory (no matter which way you look, the temperature of the universe is uniform to within a very small tolerance), so cosmologists invented “inflation” to explain it. Inflation does explain this, but nobody appears to know the mechanism of inflation, and I haven’t seen anyone claim to have proof that it actually occurred. But, if it did, it fits the observations.
In the same vein, stars orbiting on the outskirts of galaxies don’t appear to be traveling at the correct speed predicted by theory and gravitational physics. So the cosmologists invented ‘dark matter’ which nobody has seen, or detected, but (whatever it is) it does patch the standard model to allow the observed behavior.
Then they noticed that the expansion of the universe appears to be accelerating, rather than slowing down as expected. So the cosmologists invented ‘dark energy’. Again, nobody has seen or detected dark energy, but again, whatever it is, it does patch the standard model to allow the observed behavior.
Then there is ‘dark flow’. The universe appears to be going somewhere. Nobody knows why, or even for sure if it is really happening.
That’s three different major things that have been invented to explain observation, and that have not so far been detected, and one anomaly that nobody seems to understand.
When cosmologists start inventing things to make the numbers work, we have to give them time to make observations to find out if these ideas are true. However, the standard model does seem to be developing a lot of cracks.
This usually happens just before somebody comes along with a new idea that fits the facts more gracefully. Maybe we are due for a new paradigm. Like Einstein’s Theory of Relativity cleared up the cracks that were beginning to be visible in Newtonian physics at the time. Or maybe the scientists will acquire evidence proving the existence of these things. It is getting interesting.
But I have the feeling that we are missing something, somewhere…