The universe is awash with strange radio signals, but astronomers have now detected a really bizarre one that repeats every hour, cycling through three different states. While they have some ideas about its origin it can’t be explained by our current understanding of physics.
It’s more that their knowing what an hour is would be impressive. Our selection of the hour as a measure of time is arbitrary outside of its specific context. It’s just 1/24th of our planet’s rotational period. We could just as easily split the day up into 10ths or 15ths or 7ths or whatever.
To broadcast a signal that’s exactly an hour long to a planet that uses the hour as a measure of time might potentially imply someone trying to reference our way of measuring time. A signal that repeats every 53.8 minutes is on a timer that isn’t specifically relevant to Earth in the same way an hour exactly would be.
That signal might be insignificant to us; but it may be their way of establishing a timescale.
The time may be derived from how long their planet takes to rotate…aka the length of one sub-unit of their day…aka 1/24th of their day.