The physics dictating one of the universe’s four fundamental forces is relatively straightforward to understand and calculate (most of the time, at least). There was excitement in the lab when we confirmed it wasn’t a fluke and that this was real vertical rolling.”The soft sphere is shown rolling down the vertical surface during laboratory tests. “The key is that as it rolls, the sphere slightly changes shape at the contact point,” Mitra explained. Regardless, Mitra and colleagues wrote that their observation “challenges our basic understanding of physics,” with practical effects extending far beyond a neat lab trick. Harnessing the physics of vertical rolling could one day be applied across soft robotics to create new machines capable of inspecting pipe interiors, exploring difficult-to-reach cave systems, and future devices destined for the moon or Mars.