Graeme Cameron

In 2000 a Cambridge professor published a paper in Nature about this desk toy. 26 years later physicists are still arguing about how it stops It's a heavy steel disk on a mirror. As it loses energy, it spins faster and louder, and then it stops dead, all at once. Turn the sound on The professor was Keith Moffatt. His math said the wobble speeds up toward infinity in a finite amount of time, the kind of infinity physicists usually only talk about inside black holes Something has to stop it first. Moffatt blamed the thin cushion of air under the disk. Others spun it in a vacuum and blamed friction instead In March 2026 a team from Harvard posted new measurements and sided with the air, at least for the final moments The toy was invented in the late 1980s by Joseph Bendik and named after Leonhard Euler, who worked out the math of spinning bodies in the 1700s A steel disk, a mirror, and 26 years of disagreement over the last second of its spin