A time crystal may sound like it’s from the pages of a science fiction novel, but it’s something that we’ve demonstrated is possible to observe, even though it may appear to go against the basic laws of nature. You might be familiar with crystals like emerald, diamond and salt. At the microscopic level, they’re made up of repeating patterns — many layers of atoms that ultimately form a physical structure. For example, a grain of salt is made up of sodium and chlorine atoms. A time crystal is similar, but instead of forming a repetitive pattern in space, an oscillating pattern is formed in time.