The First Halt in Nuclei Production
There are no stable combinations having a total of either five or eight nuclear particles. The lack of them impeded the formation of larger combinations. To make nuclei with nine or more nucleons the heat and pressure must last long enough for many collisions between the unstable combinations and the lighter elements. The rapidly falling temperature and pressure of the first morning prevented the formation of elements more complex than hydrogen, helium, and lithium while the early universe was cooling in the first few minutes.
Most collisions were between two nuclei. Triple collisions can make heavier elements. For example, ordinary helium (two protons and two neutrons) can make carbon (six protons and six neutrons) if three helium nuclei collide nearly simultaneously. But by the time there was enough helium to make triple collisions probable the mixture had cooled and the collisions were not energetic enough to overcome the mutual repulsion of the positive charges on the nuclei.
The heavy nuclei could not be formed in the first morning. They had to wait until the morning of the second day, when low-mass elements kept on colliding for millions of years in the interiors of the first stars.
Most collisions were between two nuclei. Triple collisions can make heavier elements. For example, ordinary helium (two protons and two neutrons) can make carbon (six protons and six neutrons) if three helium nuclei collide nearly simultaneously. But by the time there was enough helium to make triple collisions probable the mixture had cooled and the collisions were not energetic enough to overcome the mutual repulsion of the positive charges on the nuclei.
The heavy nuclei could not be formed in the first morning. They had to wait until the morning of the second day, when low-mass elements kept on colliding for millions of years in the interiors of the first stars.