Distinguishing black holes and wormholes with orbiting hot spots

TL;DR

This paper proposes that future high-resolution observations of hot spots orbiting supermassive objects could distinguish between black holes and wormholes, providing a way to test the true nature of these objects.

Contribution

It introduces a method to differentiate black holes from wormholes based on the size of the photon capture sphere observed via hot spot imaging.

Findings

Wormholes have a smaller photon capture sphere than black holes.

The size of the photon capture sphere is independent of hot spot models.

Future observations could unambiguously identify wormholes versus black holes.

Abstract

The supermassive black hole candidates at the center of every normal galaxy might be wormholes created in the early Universe and connecting either two different regions of our Universe or two different universes in a Multiverse model. Indeed, the origin of these supermassive objects is not well understood, topological non-trivial structures like wormholes are allowed both in general relativity and in alternative theories of gravity, and current observations cannot rule out such a possibility. In a few years, the VLTI instrument GRAVITY will have the capability to image blobs of plasma orbiting near the innermost stable circular orbit of SgrA$^*$, the supermassive black hole candidate in the Milky Way. The secondary image of a hot spot orbiting around a wormhole is substantially different from that of a hot spot around a black hole, because the photon capture sphere of the wormhole is much smaller. The radius of the photon capture sphere is independent of the hot spot model, and therefore its possible detection, which is observationally challenging but not out of reach, can unambiguously test if the center of our Galaxy harbors a wormhole rather than a black hole.