The Helium Abundance

In the mid 1950s the cosmological theory taken seriously by most physicists was the steady state theory. In the late 1940s George Gamov had suggested that the elements had been created in the big bang when the universe was very small, dense and hot. But the work of Hoyle and Fowler was showing that the abundance of the elements could much more satisfactorily be explained in terms of nuclear synthesis inside of stars.
This nuclear synthesis also explained the energy source in stars and the various stages of stellar evolution. What need was there to propose some gigantic, cataclysmic explosion?
Hoyle soon found a need. Most of the energy released in nuclear synthesis in stars results from the burning of hydrogen to form helium. By observing how much energy is released by stars, you can estimate how much helium should be produced. By the early 1960s Hoyle began to realize that nuclear synthesis could not produce enough helium to explain the observed cosmic abundance of 25%. In a 1964 paper with R. J. Taylor, Hoyle himself suggested that perhaps much of the helium was created in an initial explosion of the universe.