Fig. 1.

Active nematic turbulence. a Fluorescence confocal microscopy micrograph of the active nematic in contact with an oil of 0.05 Pa s (see Supplementary Movie 1 where positive defects are tracked). b Snapshot of the time evolution from solving the continuum equations of motion, showing active turbulence. A comet-like, +1/2, and a trefoil-like, −1/2 defect are highlighted in each case. c Particle alignment and velocity fields around ±1/2 topological defects in extensile and contractile active systems. d Experimental distribution of vortex sizes in an active nematic in the regime of active turbulence, adapted from data in ref. ¹⁵, Nature Publishing Group. The solid line is an exponential fit to the data