One of the universe's most precise "clocks" is slowing down rapidly.

Using FAST, scientists have identified a millisecond pulsar — PSR J0435+3233 — that is slowing down about 100 times faster than expected. These objects are typically extremely stable, rotating hundreds of times per second with little change over time.

This result suggests that standard models may not tell the whole story — and that these cosmic "timekeepers" could form in more than one way.