Modern cosmology begins with Einstein's 1917 paper where he applies his General Relativity (GR) Theory to Cosmology.
After that day many discoveries have been performed and many successes in the theoretical knowledge have been achieved.
Nowadays, the opinion of many physicists is that the Universe is well-described by what Fred Hoyle termed a Big Bang Model, according to which the Universe expanded from a denser hotter stage to its current state, where the present energy budget is dominated for ~ 76% the by dark energy and for ~ 20% by dark matter (neither of which have never been detected in the laboratory), while the stuff which biological systems,
planets, stars, and all visible matter are made of (the remaining 4% in baryons) represents a very small tracer on this dark sea, with the electromagnetic radiation being an even less significant contribution...
