Bubble Experiment Finds Universal Laws

Charlie Wood | Quanta Magazine
Friday, August 30, 2019

Physicists have found examples of “universality” in a system of confined bubbles. The work could help researchers understand the strange behavior of singularities.

As Charlie Wood writes for Quanta Magazine, "each time a drop drips from a faucet, nature performs a magic trick. Breaking one blob into two calls for passage through a singularity — a single point where physical quantities flirt with the infinite. As the neck connecting the two blobs thins to nothing, the fluid pressure and speed race upward toward infinity, as if they were being divided by zero. Here, the equations used to describe fluids suffer a mathematical explosion. Order returns only after the sudden break.

Regardless of how they start, the events that produce droplets, Wood describes, play out the same way every time -- a phenomenon known as "universality."

"A recent study has identified universality in a new system: bubbles trapped in a narrow tube. The work comes as something of a surprise, since bubbles historically were the system that taught physicists the limits of universality. Now researchers have a way to turn that universality on and off."

Work by the Ruben Juanes lab in MIT's EAPS and ERL reveals that bubbles do have some form of universality, and that it can be "switched" on and off in some systems. The work has exciting implications for research like that of black holes.

Read the full story in Quanta Magazine.

Story Image: All droplet formation was once thought to be universal. (Credit: Xiangdong Shi and Sidney Nagel)