Wormholes are shortcuts in spacetime, throat-like links between otherwise distant parts of the Universe. There's no evidence that they exist but they do arise mathematically as stable solutions to the equations of relativity, just like other exotic objects such as black holes.

There's good evidence that black holes exist so astrophysicists can't simply dismiss the other solutions. In fact, they've devoted a good deal of time and effort to working out how wormholes might form, what they would look like and what might keep them open.

But in thinking about wormholes, they've tended to imagine them as empty tunnel-like superhighways between one region of empty space and another.

But Vladimir Dzhunushaliev at the Eurasian National University in Kazakhstan and a few pals have a different idea. They say there's no reason why wormholes can't be packed full of matter. And today they unveil the properties of such objects.

They begin by imagining an ordinary star or a neutron star with a wormhole at its heart. "For a distant observer, such a star would very much look like an ordinary star," they say.

However, there would be some important differences. For a start, this star would have to have a twin at the other end of the wormhole. These stars would be like Siamese twins, joined at the hip by the most bizarre of connections.

Natural, or primordial wormholes have been speculated about for years. To read the rest of the article, click here.