One Day on Two Orbits

One Day on Two Orbits is a floor sculpture by Nadia Kaabi-Linke that shows the shadows of a bicycle on the ground over a day, following the transition from day to night, from sun to moon. While the bicycle is invisible, the shape of the revolving shadow forms an image reminiscent of astronomical photographs of distant galaxies. The work pays homage to Ibn Al-Haytham, who introduced the idea that the sun and moon revolve on geometrically and temporally different orbits. One Day on Two Orbits is a memorial to a discovery that relocated the Earth in the solar system, and harmonised different cultures of time.