From Interstellar to Star Wars, science fiction is filled with stories of how humans might travel through the universe to visit distant worlds.
But even with our most advanced modern rockets, travelling to the edges of our own solar system might take most of a human lifetime.
However, scientists say that there is a way humanity could travel millions of light years in seconds.
By passing through wormholes in the fabric of space and time itself, we might be able to travel to the most distant stars with ease.
A wormhole, much like a black hole, is a structure which arises when gravity is so strong that it bends the fabric of the universe.
Einstein’s theories about the universe predict that spacetime can be bent in such a way that it creates a ‘bridge’ between two different points in the spacetime.
Professor Dejan Stojkovic, a cosmologist from the University at Buffalo, told MailOnline: ‘Theoretically, there is no limit on how far we could travel that way.
‘Two distant points could be billions of light years away along the regular space, and only a few seconds away along the wormhole.’
Science fiction films like Star Wars (pictured) often imagine how travellers might leap from star to star in just seconds. Now, scientists say this really could be possible using wormholes
What are wormholes?
Dr Andreea Font, a theoretical astrophysicist from Liverpool John Moores University, told MailOnline: ‘Wormholes are “tunnels” in the fabric of space and time that can shortcut the normal path between two far-away regions in our universe.’
According to Einstein, an object with mass warps the fabric of spacetime like a weight being dropped onto a rubber sheet. These curves are what create the force of gravity.
But Einstein’s equations also have some extremely weird solutions when gravity starts to become extremely strong.
‘For example, we know that black holes can bend the space around them under the influence of gravity,’ says Dr Font.
‘In principle, the geometry of space-time can be folded and bent in such a way that a tunnel can be established between two massive black holes at faraway places.’
The connection between these distant points is what scientists call a wormhole.
Where this tunnel emerges into space is called the mouth and the tunnel is called the throat.
A wormhole is a structure formed when intense gravitational forces fold spacetime over on itself and make a bridge connecting two points
A wormhole is made up of two mouths which could be anywhere in the universe, and a throat which connects them.
Can wormholes be used to travel through space?
In Einstein’s view, spacetime isn’t flat, but curved, crumpled, and bent by the forces of gravity.
Professor Stojkovic explains that wormholes take advantage of these folds, punching right through from one point to another.
Instead of taking the long journey over the curving surface of spacetime from one point to another, we can just take the direct route through the throat of the wormhole.
It doesn’t even matter how far apart the mouths are in conventional space, with enough folding from gravity they can be almost touching in spacetime.
In theory, humans might be able to exploit this fact to travel enormous distances in just seconds.
Professor Stojkovic says: ‘If the wormhole’s throat is large enough to fit a spaceship, then we can use the shortcut that the wormhole provides.’
Like falling into a black hole as imagined by Interstellar (pictured), a wormhole’s intense gravity could allow you to travel billions of light years across the universe in seconds or even travel through time
Provided there is a wormhole mouth at your starting point and another at your destination, you could travel anywhere in the universe faster than the speed of light.
How to build a warp drive
Although this is fantastic in theory, the difficult part is keeping a wormhole open long enough for you to safely pass through it.
Dr Font explains: ‘Wormholes come in two categories, some are traversable and some are not.
‘Of those that are traversable, meaning that the path between the two ends remains open, it is not always possible to keep it open long enough for actual travel to take place.’
Because of the intense gravitational forces involved in folding spacetime, wormholes are very unstable and the throat is likely to collapse in on itself.
To get around this any future ‘warp drive’ technology would need a way of holding the wormhole’s mouth open for long enough to traverse it.
Professor Stojkovic says: ‘To provide stability one has to counter the attractive force of gravity and prevent the collapse of the wormhole walls.
But if we want to have a warp drive like in Star Trek, this will require finding a way to hold a wormhole open for long enough to pass through
Because of the strong gravity involved, wormholes will naturally collapse in on themselves. To avoid this an advanced civilisation could use ‘negative energy’ to hold the tunnel open
‘For that, we either need large amounts of negative energy, or some equivalent setup which would provide repulsive force to stabilize the wormhole.
In physics, ‘negative energy’ occurs when a region of space has less energy than the surrounding empty void of space.
Although this sounds like something out of science fiction, negative energy is a consequence of quantum physics and scientists have managed to make small amounts under laboratory conditions.
However, the amount of negative energy required to stabilise a traversable wormhole far exceeds anything humanity is able to produce.
Professor Stojkovic says: ‘Currently we have such capabilities. But this does not mean that we will not have them in a distant future, nor that some alien civilization does not have them now.
‘Finally, human building power is hardly capable of competing with the building power of nature. So nature-made wormholes may already exist, and we may take advantage of them someday.’
Are wormholes real?
However, if we want to build a warp drive out of natural wormholes we might encounter a pretty major problem.
While we don’t have any evidence for wormholes right now, like black holes they are predicted by Einstein’s theories of relativity. Just as we have now observed black holes for the first time, scientists hope we might one day be able to observe wormholes. Pictured: An image of the black hole at the centre of the Milky Way
While wormholes are theoretically possible, scientists don’t have any direct evidence that they exist.
That could be because wormholes are extremely difficult to detect, or it might just be because they don’t exist in our universe.
Since wormholes are so inherently unstable, some scientists think they couldn’t possibly exist in reality.
This has led some scientists to suggest that wormholes might be nothing more than a useful theoretical tool to help think about Einstein’s equations.
However, scientists are now developing the tools to find wormholes if they are out there, and Professor Stojkovic is optimistic that the evidence will arrive someday.
‘Nature, whose building power is much superior to human one, always finds a way to build something which is described by solutions of legitimate theories like General Relativity.
‘The Schwarzschild solution describing black holes was derived in 1916, and leading scientists for the next 50 years simply refused to believe there is anything in nature which is that strange.
‘Today, we see black holes everywhere in the universe. I believe something similar will happen with wormholes.’
EINSTEIN’S GENERAL THEORY OF RELATIVITY
Albert Einstein
In 1905, Albert Einstein determined that the laws of physics are the same for all non-accelerating observers, and that the speed of light in a vacuum was independent of the motion of all observers – known as the theory of special relativity.
This groundbreaking work introduced a new framework for all of physics, and proposed new concepts of space and time.
He then spent 10 years trying to include acceleration in the theory, finally publishing his theory of general relativity in 1915.
This determined that massive objects cause a distortion in space-time, which is felt as gravity.
At its simplest, it can be thought of as a giant rubber sheet with a bowling ball in the centre.
Pictured is the original historical documents related to Einstein’s prediction of the existence of gravitational waves, shown at the Hebrew university in Jerusalem
As the ball warps the sheet, a planet bends the fabric of space-time, creating the force that we feel as gravity.
Any object that comes near to the body falls towards it because of the effect.
Einstein predicted that if two massive bodies came together it would create such a huge ripple in space time that it should be detectable on Earth.
It was most recently demonstrated in the hit film film Interstellar.
In a segment that saw the crew visit a planet which fell within the gravitational grasp of a huge black hole, the event caused time to slow down massively.
Crew members on the planet barely aged while those on the ship were decades older on their return.
