Many examples of failures of those tests have been shown. For example, if the universe started as a very high concentration of matter, it can be calculated that it was then a Black Hole. However, relativity shows that Black Holes cannot expand. The Big Bang is therefore incompatible with the early expansion of the universe when relativity is taken into account as shown previously. Before understanding the origin of the 3 K radiation observed in space, we need to know the properties of matter filling space.
Atomic hydrogen is composed of an electron electrically bound to a proton forming neutral hydrogen.
In a hydrogen atom, those spins are coupled either parallel or anti parallel. The actual observation of the 21 cm. It is well known in basic physics and chemistry that atomic hydrogen H is quite unstable. This is unlike helium and other inert gases that remain mono-atomic. Atomic hydrogen reacts so readily, that it is impossible to buy or keep any quantity of stable atomic hydrogen, because atoms of atomic hydrogen combine in pairs, to produce very stable bound H 2 molecules.