Two new kinds of time crystals.

Science News looks at a strange structure of matter (one we’ve discussed on here in the past) that regularly repeats itself like a crystal… but the repeated structure is in time, not space. Instead of these molecules forming a 45-degree angle every 5 nanometers, for instance, these ions might flip their atomic nuclei every 5 nanoseconds. Flip. Flip. Flip. Now, we’ve created “fricking weird” time crystals in two more forms of matter:

A team of scientists created a time crystal in a solid material called monoammonium phosphate, the researchers report in both the May 4 Physical Review Letters and the May 1 Physical Review B. Another team made its time crystal in a type of liquid containing star-shaped molecules, according to a study also published in the May 4 Physical Review Letters.

Both time crystals rely on a quantum property called spin, which makes some atomic nuclei seem to whirl like a top. In the time crystals, the direction of that spin flipped at regular intervals.

Repeated radio wave pulses were used to trigger the spins’ flip-flopping. But even when the spins weren’t flipped perfectly, both materials kept up a regular pattern of flipping, revealing that they had a preferred time structure.