Concentric Floater

Photo date: April 21, 2015. Photographer: Mark Mahin.

The photo below was taken in Grand Central Station in New York.

Below is a closeup of the orb. We see an unusual structure that seems to show concentric rings.

How do we know this isn't a dust particle? Two reasons: (1) when dust particles are photographed near the camera, they don't look anywhere near this bright; (2) when dust particles are photographed near the camera, they don't have concentric rings like this.