BBN - The Bottom Line


The theory of Big Bang Nucleosynthesis is very well developed:
Required input data can be measured in lab.
For a given density of ordinary matter in the Universe the theory confidently predicts the amounts of light elements that should be observed.

D to H ratio in distant gas clouds indicates that the density of ordinary matter is about 4% of the total.

...this agrees exactly with the value determined from the unevenness of the CMB