Video URL http://pirsa.org/21090016
The advent of black hole imaging has opened a new window into probing the horizon scale of black holes. An important question is whether string theory results for black hole physics can predict interesting and observable features that current and future experiments can probe.
I will discuss the physical properties of four-dimensional, string-theoretical, horizonless “fuzzball” geometries by means of imaging their shadows. Their microstructure traps light rays straying near the would-be horizon on long-lived, highly redshifted chaotic orbits. In fuzzballs sufficiently near the scaling
limit this creates a shadow much like that of a black hole, while avoiding the paradoxes associated with an event horizon.
Finally, I will consider comparing such fuzzball images to their black hole counterparts. In particular, detailed measurements of higher order photon rings have the potential to discriminate between fuzzballs and black holes in future observations.