How to tell the difference between a regular black hole and a wormhole

Physicists have worked out how to see whether a black hole is actually a wormhole that could theoretically be travelled through – but we can’t tell yet with the black holes we have observed

By Leah Crane

We might be able to tell the difference between a wormhole – a tunnel that connects two black holes at different locations in space-time – and a regular black hole using light that has travelled in circles around the black hole’s mouth. If wormholes exist, this could finally allow astronomers to spot them.

In 2019, astronomers used a network of radio observatories called the Event Horizon Telescope (EHT) to take the first direct image of a black hole, a distant behemoth called M87*. Petya …