Opposition effect on road surface

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    Roads, beach sand and other surfaces sometimes show an opposition effect.   

In these images, by Eva Seidenfaden (site), the sun was very low. The worn road surface had a layer of mud and small stones from nearby construction work.

In the right hand image the glow surrounds Eva's head where the camera's shadow is also situated. On the left the camera is held away and the glow moves with its shadow. Compare this to Cernan's shadow on the Moon and to that of the "wet" heiligenschein.

The glow is very subtle. When searching for it, walk slowly or move the head back and forth. It is not always there. I once saw it clearly in the sand of a nearby beach. Needless to say I did not have a camera and it has not (yet) appeared there again. On that day the sand grains must have been stacked in tower like structures which cast deep shadows into their interstices.