But astrophysicists from the International School for Advanced Studies in Trieste, Italy, claim it is mathematically possible for a portal to have been created by dark matter in the middle of the Milky Way.
"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," said Professor Paulo Salucci.
"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 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 Salucci.
"Obviously we're not claiming that our galaxy is definitely a wormhole, but simply that, according to theoretical models, it is a possibility."
Other "spiral" galaxies similar to the Milky Way - such as its neighbour Andromeda - might 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: "Our 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 constructing 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."
The theory was published in the journal Annals of Physics.
Wormholes
• Wormholes are areas where space and time are bent so that distant points are closer together.
• Any wormholes existing in nature have previously been assumed to be microscopic pinpricks in the fabric of space-time.
• But one possibly lying at the centre of the Milky Way would be large enough to swallow a spaceship and its crew.