AS102 Study Guide - Midterm Guide: Nucleosynthesis, Beryllium
Document Summary
By the end of the era of nucleosynthesis the universe was. 5 minutes old and the temperature had dropped to a billion k. during this era protons and neutrons began to fuse together to form nuclei. Remember that hydrogen has one proton but no neutrons so a proton by itself could be considered a hydrogen nucleus; a proton and a neutron together for the nucleus of deuterium; two deuterium nuclei fuse together to form helium. Elements beyond lithium (element #3) and beryllium (element #4) could not be created. Even lithium and beryllium were created in very small quantities. This era lasted until the universe was about 380,000 years old and the temperature had dropped to about. The photons bounced around from electron to electron and didn"t travel very far between collisions. The universe was opaque, much like a very, very thick fog.
