Nuclear fusion occurs more slowly than was thought of in the stars, which has led a group of Italian astrophysicists to affirm that the stars are older than has been calculated so far.
Italy's Underground Nuclear Astrophysics Laboratories have used an underground particle accelerator to measure the speed of the carbon-nitrogen cycle (CNO). The CNO cycle is the main process involved in nuclear fusion and, knowing the speed of this process, older stars estimate that they are 700 million years older than was thought. The oldest stars seem to be fourteen billion years old.