Answer: Stellar turbulence
This computer-rendered image depicts a Rayleigh-Taylor instability: a turbulent, gravity-driven mixing of fluids that occurs in stars (and in boiling water) when a heavy substance sits atop a lighter one.
Astrophysicists at the University of Minnesota conducted a supercomputer simulation of sun-like stars to model this turbulence, which violently but effectively circulates heat in the region just below the stellar surface.
