Key takeaways Raising the energy state of an atom’s nucleus using a laser, or exciting it, would enable development of the most accurate atomic clocks ever to exist. This has been hard to do because electrons, which surround the nucleus, react easily with light, increasing the amount of light needed to reach the nucleus. By causing the electrons to bond with fluorine in a transparent crystal, UCLA physicists have finally succeeded in exciting the neutrons in a thorium atom’s nucleus using a mode...