This might be a good thread for me to seek some information from those who know. The lack of radioisotopes with half-lives less than about 80,000,000 years on the Earth is good evidence that it has to be billions of years old. The usual YEC explanation is there was a period of rapid decay at Creation and during and/or after the Flood. I believe the short-lived isotopes are observed to appear and disappear as expected in supernovae. My question is :- have the same radioisotopes been observed to be absent in the Sun and in Moon rocks? If so this would mean YEC would have to explain why Sun and Moon were affected by the Flood's episode of rapid decay. Are the isotopes with shorter half-lives e.g. 1 My able to be observed in younger stars? If so that would suggest the Sun did not have to be made without them. Thanks to any who can enlighten me. As a related thought I wonder if isotope abundance is how a star is determined to be young.