No, those aren’t false color sunspots swirling around the Sun’s surface, it’s paint mixing with gasoline.
The Marangoni Effect is a fancy phrase for a concept you might have experimented with before. Have you ever made a soap-powered boat? Or dipped some soap in the middle of milk with droplets of food coloring? What you’re seeing is the Marangoni Effect, which describes how fluids can flow when there is a difference in surface tension.
Think about the surface of an inflated balloon. All of the stretchy rubber is trying to return to its non-inflated shape, and in turn there is a contracting force that is pulling every piece of the balloon towards the other. The same thing happens with surface tension. The reason that water will form droplets on a freshly waxed car, for example, is that water has a relatively high surface tension that pulls the fluid in on itself like tiny balloons.
When two fluids of different surface tensions meet, at the surface of the combined fluid there will be a battle. But the fluid with the weaker surface tension won’t survive the fight. “Marangoni Flow” is the name of this surface skirmish, and it’s what happens as fluid with a lower surface tension flows towards fluid with a higher surface tension. This is why colored milk rapidly spreads apart when a drop of soap enters the fray — the drop of soap is being ripped asunder from every possible angle.
Ultimately, the Marangoni Effect is why the video above is so mesmerizing. The surface tension battle between the paint and the gasoline rages on and the camera captures all the disorienting action as Marangoni Flows flow. In fact, it’s so pretty it’s making us sick. But like, a gorgeous kind of sick.
IMAGES: Shawn Knol