Seeking out wormholes

It’s currently impossible to tell the difference between a wormhole and a black hole, but there are ways it could be done

1 Gravitational lensing

In 2008, two scientists from Gurucharan College, Silchar, India, investigated whether wormholes could, like black holes, exhibit gravitational lensing of light that passes by them. They discovered that one type of wormhole, the Ellis drainhole, the earliest known complete mathematical model of a traversable wormhole by Homer G. Ellis, and separately Kirill A. Bronnikov, does not exhibit this lensing. Therefore a black hole-like structure that doesn’t bend light might well be a wormhole.

2 Leaky gravity

If a wormhole enters our universe, or our part of the universe, and there is mass on the other side of it, then it will generate gravity. This can pass through the wormhole and add to the gravitational pull, either perturbing the orbits of objects around the wormhole mouth or adding to its pull so it appears to exert more gravity than its size would account for.

Having too much gravity could make a wormhole stand out from otherwise identical black holes.

3 Gamma rays

Research from scientists in Saint Petersburg, Russia, has shown that while black holes, particularly those at the centre of active galaxies, can release gamma rays as a relativistic jet, the rays released from a wormhole are more likely to be in a sphere, as it has no event horizon.

This radiation would also have a distinct spectrum, acting as a marker to tell the different types of hole apart.