elements change time elements isotopes much abundant others theory initially proposed fred hoyle ref name hoyle later refined ref name hoyle ref advances made especially nucleosynthesis neutron capture elements heavier iron margaret geoffrey burbidge william alfred fowler hoyle famous b sup sup fh paper ref name b fh ref became one heavily cited papers astrophysics history stars evolve changes composition abundance constituent elements lifespans
Natural science Space science Stellar astrophysics Stellar nucleosynthesis