A cause for concern

We have a Big Bang theory of the birth of the cosmos and only the known forces to account for the presently observed universe.  The theory says that, by the time the cosmos was about 400,000 years old, matter on the small scale had evolved into hydrogen and helium.  But describe just the forces to explain how atoms of hydrogen and helium are the way  that they are and you get no answer.  So why should such forces alone explain how galaxies are the way that they are of how stars and planetary systems form?

Construct a quantum theory that rules out the possibility that anything exists apart from matter/energy and the push or pull forces as causes, and you are stuck with a cosmology that requires the addition of vast amounts of mysterious and invisible matter and energy, plus a theory of the early cosmos that defies relativity, to possibly explain how the universe is the way that it is