Their work also shows that under certain conditions, an observer from Earth could see two photon rings - one from "his" side of the universe, around "his" end of the wormhole, and the other from the opposite end. A very important moment could then be if the photons from "our" side travel through the wormhole in the direction of its opposite end, but due to the fact that they do not have enough energy, they would "bounce" back. That would cause loss of the energy and thanks that, they could be clearly distinguished. In addition, due to the different size of the photon ring at the other end of the wormhole, their light trace would have a different shape. If we were able to observe these photons, we could not only confirm the existence of wormholes, but also learn interesting information about the universe at the other end of the wormhole.