266. Sphere at M=1.53 A shadowgraph catches a 1/2-inch sphere in free flight through air. The flow is subsonic behind the part of the bow wave that is ahead of the sphere, and over its surface back to 45 deg. At about 90 deg. the laminar boundary layer separates through an oblique shock wave, and quickly becomes turbulent. The fluctuating wake generates a system of weak disturbances that merge into the second shock wave. Photograph by A.C. Charters