Using images from the Hubble Space Telescope Wide-Field Camera 3 , we measure the rate of diffusion of stars through the core of the globular cluster 47 Tucanae using a sample of young white dwarfs identified in these observations .
This is the first direct measurement of diffusion due to gravitational relaxation .
We find that the diffusion rate \kappa \approx 10 - 13 arcsecond ^ { 2 } Myr ^ { -1 } is consistent with theoretical estimates of the relaxation time in the core of 47 Tucanae of about 70 Myr .