In August 1834, a Scottish engineer named John Scott Russell was conducting experiments along Union Canal with an eye toward improving the efficiency of the canal boats. One boat being drawn by a team of horses stopped suddenly, and Russell noted a solitary wave in the water that kept rolling forward at a constant speed without losing its shape. The behavior was unlike typical waves, which tend to flatten out or rise to a peak and topple quickly. Intrigued, Russell tracked the wave on horseback for a couple of miles before it finally dissipated in the channel waters. This was the first recorded observation of a soliton.
Russell was so intrigued by the indomitable wave that he built a 30-foot wave tank in his garden to further study the phenomenon, noting key characteristics of what he called “the wave of translation.” Such a wave could maintain size, shape and speed over longer distances than usual. The speed depended on the wave’s size, and the width depended on the depth of the water. And if a large solitary wave overtook a smaller one, the larger, faster wave would just pass right through.
Russell’s observations were largely dismissed by his peers because his findings seemed to contradict what was known about water wave physics at the time. It wasn’t until the mid-1960s that such waves were dubbed solitons and physicists realized their usefulness in modeling problems in diverse areas such as fiber optics, biological proteins and DNA. Solitons also turn up in certain configurations of quantum field theory. Poke a quantum field and you will create an oscillation that usually dissipates outward, but configure things in just the right way and that oscillation will maintain its shape — just like Russell’s wave of translation.
Because solitons are so stable, Lim believes they could work as a simplified toy model for the dynamics of bubble collisions in the multiverse, providing physicists with better predictions of what kinds of signatures might show up in the CMB. If his hunch is right, the expanding walls of our bubble universe are much like solitons.Me: I've long been attuned to odd connections between seemingly unrelated topics, but this one really stretches far. I'm impressed.
* - Fixed my misspelling of the author's name.