A series of public clocks displaying the time on spacecraft orbiting Earth

The Relative Clocks were commissioned by the UK Space Agency as part of their Arts and Technology outreach program. The clocks seek to convey that time is a malleable force in our world, and that we can measure how it changes under various conditions.

Each clock in the series represents the time travel of a different spacecraft. One hand ticks at the time on earth, while the other hand ticks at the time on the spacecraft. Due to the differing forces of speed and gravity the spacecraft have experienced, the hands now tick separately. The gap will continue to grow, as the spacecraft travel further in time.

The Relative Clocks are a representation of time dilation, the effect of general and special relativity on the flow of time.

The front hand of the clock displays the time on a spacecraft, while the rear hand displays the time on Earth. The delay between the tick of the front and rear hands indicates the time difference between Earth and the spacecraft.

This difference is constantly growing, as each second on the spacecraft is slightly longer or shorter than a second on earth. The clocks update every day to reflect the constant effects of relativity on the spacecraft.