Ask Doctor Universe

Asked by Danielle of Latrobe, Tasmania.

Dear Danielle,

Movies not only took the ideas and inventions of people, but also the work of a horse. Her name was Sallie Gardner and the debate of her day was whether or not horses ever had all four hooves off the ground during a gallop.

The human eye moved too slowly to see what was going on with horses’ hooves, so in 1872, the governor of California hired photographer Eadweard Muybridge to find out.

Muybridge set up big cameras around a track to capture Sallie Gardner in motion. He discovered in one of the photos that, for a moment, she was in mid-air...