Each time that energy pulse travels, it tends to push one clock's pendulum in time with the other. The experiment takes up to 18 hours or even days to run, because the clocks synchronize slowly.

Those devices are recent inventions— the late 1600s for the pendulum clock, and circa 1970 for the digital clocks— making it seem like timekeeping is a recent phenomenon.

‘Grandfather clock’ got its name from song Antiques: Originally described as ‘long case’ or ‘tall case.’ it is of a type first made in England in the 1600s.

Christiaan Huygens knew clocks. The Dutch scientist, mathematician and inventor-of-all-trades is credited with inventing the pendulum clock and developing one of the first balance spring watches ...

In the 100 days since it was sealed, Clock B has only lost five-eighths of a second, setting a Guinness World Record for “most accurate mechanical clock with a pendulum swinging in free air.” ...

Lab experiments suggest that a strange synchronization of pendulum clocks observed in the 1600s can be chalked up to acoustic energy Jesse Emspak Christiaan Huygens was a busy scholar. Among his ...