From 2000, Livio focused his research on supernova explosions and their use in determining the rate of expansion of the universe. He has also studied so-called dark energy, black holes, and the formation of planetary systems around young stars. He has contributed to hundreds of papers in peer-reviewed journals on astrophysics. In 2009, the American Association for the Advancement of Science (AAAS) Council elected him as a Fellow of the AAAS. Livio was cited for his "distinguished contributions to astrophysics through research on stars and galaxies and through communicating and interpreting science and mathematics to the public." He is also cited in the American Men and Women of Science.