This composite photo shows the arc of the sun over Lulworth Cove in England during the December solstice. The low sun angle reveals a distinctive circular diffraction pattern of waves inside the cove. Along the shoreline, the beach has eroded into a regular, arc-like pattern known as beach cusps. Although there are multiple theories about how cusps form, their pattern is self-sustaining. They consist of a horn of coarse materials that projects into the water and an arc of finer sediments called an embayment. When incoming waves hit the horn, they slow down, depositing heavier coarse sediment on the horn while lighter, fine particles are carried further ashore. (Image credit: C. Kotsiopoulos; via APOD; submitted by jshoer)
Beach Cusps
