Chasing the Age of the First Stars
The ages of the oldest stars in the Galaxy indicate when star formationbegan, and provide a minimum age of the Universe. Radioactive dating ofmeteoritic material and stars relies on comparing the present abundanceratios of radioactive and stable nuclear species to the theoreticallypredicted ratios of their production. The radioisotope 232 Th (half life14 Gyr) has been used to date Galactic stars,