• There are some clocks, mostly in or around international airports, which have multiple faces to show the time at various cities around the world. • Taking more a forward-looking approach is [Chronova Engineering], whobuilt a clockto display the time on four different planets: Earth, Mars, Jupiter, and Saturn. • The clock doesn’t have any hands, but it uses rotating dials to represent a top-down view of each planet from it’s north pole. • The dials have degree markings to represent rotation relative to each planet’s prime meridian; for the gas giants, rotation is measured by the rotation of the planet’s core. • Each dial’s center is made out of a circular stone tile with patterns similar to those seen on the planet; Earth, for example, is represented with sodalite. • Three pointers mounted around the dial indicate the longitudes which are currently experiencing sunrise, noon, and sunset.

Article Summaries:

  • Chronova Engineering has built a mechanical display that shows the relative rotation of Earth, Mars, Jupiter, and Saturn. The device uses four rotating dials-each a top‑down view of a planet’s north pole-mounted on a brass and steel framework. Degree markings indicate each planet’s rotation relative to its prime meridian, while three pointers on each dial mark the longitudes of sunrise, noon, and sunset. The system is driven by nine gears, including idler gears spaced by a pantograph‑milled cutout, and is operated by a handle or knob. Though it lacks a traditional time‑keeping mechanism, the clock accurately represents planetary motion and echoes Chronova’s earlier orrery work.

Sources: