Went down the rabbit hole on this. There are bacteria in your gut right now with tiny electric motors built into them. Each motor is 45 nanometers wide, about 2,000 times thinner than a human hair. It spins faster than a Formula 1 engine. After 50 years, scientists just cracked how it works. The motor spins a corkscrew-shaped tail so the bacterium can swim. At that tiny scale, water feels as thick as tar. Moving anywhere takes serious power. A single E. coli cell (the kind in your gut) spins its motor at 18,000 RPM. That beats modern Formula 1 engines, which redline around 15,000. Some bacteria in the ocean run theirs at 42,000 RPM, nearly triple. And the motor barely wastes any energy as heat. Your car engine loses most of its fuel to heat. This thing loses almost none. Inside the motor, 5 proteins form a ring wrapped around 2 proteins in the middle. Five can't split evenly into 2. The resulting lopsidedness is what makes the whole thing work. Protons, which are tiny charged particles, get pulled from outside the cell through the motor. Each one grabs a center protein, then lets go. In letting go, it tugs the outer ring a fraction of a turn. Another proton does the same thing on the other side. Then another. It's like two feet alternating on bicycle pedals. Over 2,000 times per second. Switching directions is a whole other trick. When the bacterium senses food running out, it tags a small messenger protein with a phosphorus atom. That tagged messenger floats over and touches one protein on the outer ring. The touched protein flips into a new shape. That flip triggers the next protein, and the next, and the next, around the whole ring, like dominos falling. The ring reshapes in milliseconds. Rotation reverses. The bacterium turns and swims somewhere else. Mike Manson, a biophysicist at Texas A&M, has been studying this one motor since the 1970s. For five decades, most of its parts stayed a mystery. Starting in 2020, a new wave of imaging let scientists see the individual pieces. The last pieces clicked into place in a March 2026 paper from Aravinthan Samuel's lab at Harvard. Manson told Quanta Magazine his lifelong quest was fulfilled. A billion years of evolution built the most efficient rotary motor on the planet. Trillions of them are spinning inside you right now.