'Space time tunnel' in Milky Way
A giant doorway to another galaxy or universe may exist at the centre of the Milky Way, a study suggests.
Scientists believe it would be possible to navigate through the wormhole, potentially a real-life version of the space-time tunnel portrayed in the hit movie Interstellar.
Wormholes allowing instantaneous travel between distant points in space and time, or even between different universes, are allowed under Einstein's theory of General Relativity.
But most scientists dismiss the idea of ever building one large and stable enough to pass through, and no natural examples have been detected.
The extraordinary new theory, published in the journal Annals of Physics, follows the discovery of what appears to be a super-massive black hole at the centre of our galaxy, the Milky Way.
According to the authors, the black hole - a region of concentrated gravity that distorts space-time - may actually be a wormhole in disguise.
The scientists, who base their conclusion on complex mathematical models, say the portal could be constructed from dark matter - invisible material making up around 26% of the universe whose nature is unknown.
Astrophysicist Professor Paulo Salucci, from the International School for Advanced Studies in Trieste, Italy, said: "If we combine the map of the dark matter in the Milky Way with the most recent Big Bang model to explain the universe and we hypothesise the existence of space-time tunnels, what we get is that our galaxy could really contain one of these tunnels, and that the tunnel could even be the size of the galaxy itself.
"But there's more. We could even travel through this tunnel, since, based on our calculations, it could be navigable. Just like the one we've all seen in the recent film 'Interstellar'".
He said the research was surprisingly close to what was depicted in director Christopher Nolan's movie, for which theoretical physicist Kip Thorne provided technical assistance.
"What we tried to do in our study was to solve the very equation that the astrophysicist 'Murph' was working on," said Prof Salucci. "Clearly we did it long before the film came out."
Any wormholes existing in nature have previously been assumed to be microscopic pinpricks in the fabric of space-time.
But the one possibly lying at the centre of the Milky Way would be large enough to swallow up a spaceship and its crew.
Prof Salucci added: "Obviously we're not claiming that our galaxy is definitely a wormhole, but simply that, according to theoretical models, this hypothesis is a possibility."
Other "spiral" galaxies similar to the Milky Way - like its neighbour Andromeda - may also contain wormholes, the scientists believe.
Theoretically it might be possible to test the idea by comparing the Milky Way with a different type of nearby galaxy, such as one of the irregular Magellanic Clouds.
In their paper, the scientists write: "O ur result is very important because it confirms the possible existence of wormholes in most of the spiral galaxies ..
"Dark matter may supply the fuel for con structing and sustaining a wormhole. Hence, wormholes could be found in nature and our study may encourage scientists to seek observational evidence for wormholes in the galactic halo region."