Typically, one imagines a black hole as sort of a gigantic cosmic pit that sucks in everything around it. But physicists say a new kind of space structure is possible that allows some information to escape black holes. Previously, wormholes, theoretical structures predicted by the theory of general relativity (as Einstein-Rosen bridges), have been considered as possible ways to escape black holes. But the physics of such potential tunnels between locations in space-time never panned out. The wormholes would collapse immediately upon forming. So scientists theorized that may be some advanced civilization could find a technology, perhaps utilizing an exotic material to stabilize the wormholes. Basically, pure sci-fi.

But now, physicists proposed that a new type of wormhole is possible, called traversable. It would be be free of exotic material and could stay open on its own.

The work on traversable wormholes was carried out by Ping Gao and Daniel Jafferies of Harvard University and Aron Wall of Stanford University. According to their 2016 paper, a repulsive negative energy can be generated by a special quantum connection between the black holes on both sides of the wormhole. With the right kind of connection, something could go from being in one black hole into the other one.

If this kind of wormhole is possible, it means there could be interiors to black holes and that you could theoretically get out of one and live to tell about it. Interestingly, the math involved in the work by the physicists on the wormholes is similar to the process called quantum teleportation, which can be demonstrated in a lab.

Here's how a traversable wormhole would work, in a graphic from Quanta Magazine:

In case you're wondering, traversable wormholes do not seem to function as time machines. Rather they support the concept of unitarity - that no information is ever lost. As John Preskill, a black hole expert from Caltech noted to Quanta Magazine, the new wormholes also protect “what we call ‘black hole complementarity,’ which means that the interior and exterior of the black hole are not really two different systems but rather two very different, complementary ways of looking at the same system."

Traversable wormholes were further explored in a recent paper co-authored by Juan Maldacena, Douglas Stanford, and Zhenbin Yang.

It bears noting that no actual wormholes have been discovered yet. This article was first published on BigThink.

Brian Greene, professor of physics and mathematics at Columbia University and co-founder of the World Science Festival, explains what we know about time travel so far. Following is a transcript of the video.

Brian Greene: I’m Brian Greene, professor of physics and mathematics at Columbia University and co-founder of the World Science Festival.

It’s critical that you realize that there are two types of time travel, and they are radically different. Time travel to the future? Definitely possible.

We know how to do it because Einstein showed us the way over a hundred years ago. It’s surprising how few people actually really know about this in their bones. He showed that if you go out into space and travel near the speed of light, and you turn around, and you come back, your clock will be ticking off time more slowly. So, when you step off it’s going to be the future on planet Earth. You will have time traveled into the future.

He also showed that if you hang out near a nice strong source of gravity — a neutron star, a black hole — and you kind of get right near the edge of that object, time also for you would slow down real slow relative to everybody else. And therefore, when you come back to Earth, for instance, it’ll again be far into the future.

This is not controversial stuff. Any physicist who knows what they’re talking about agrees with this. But the other kind of time travel — to the past is where the arguments start to happen because many of us don’t think that time travel to the past is possible.

The main proposal that people at least consider worthy of attention for traveling to the past does make use of a weird concept called wormholes. A wormhole is something that really … Albert Einstein again discovered. The guy has like got his name written over everything in this field.

It’s a bridge, if you will, from one location space to another. It’s kind of a tunnel that gives you a shortcut to go from here to here. Now he discovered this in 1935 but it was subsequently realized that if you manipulate the openings of a wormhole — put one near a black hole or take one on a high-speed journey — then time of the two openings of this wormhole tunnel will not take off at the same rate, so that you will no longer just go from one location in space to another, if you go through this tunnel — through this wormhole — you’ll go from one moment in time to a different moment in time. Go one way, you’ll travel to the past, the other way, travel to the future.

Now again, we don’t know if wormholes are real. We don’t know if they are real whether you’ll be able to go through them. So, there are all sorts of uncertainties here. Most of us think that you’re not going to actually go on a whirlwind journey through a wormhole to the past. But it’s still not ruled out.

References: Business Insider

Wormholes have long been considered to exist only in the realms of science fiction, but some physicists believe the theoretical portals could be real, and there could be one relatively close by.

Wormholes, which were predicted by Einstein in his theory of General Relativity, are areas where space and time are bent to manipulate the distance.

It would take a huge mass to produce the manipulation of spacetime, and no natural examples have ever been found.

However, experts from the International School for Advanced Studies in Trieste, Italy, say they are possible, and could be hiding within dark matter inside the Milky Way.

Professor Paulo Salucci, 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'."

Scientists had believed any wormholes which exist in the universe could simply be the size of a pin prick.

However, the team of astrophysicists say the one in our galaxy could be big enough to fit a spaceship which could traverse the cosmos, as they would likely exist in other spiral galaxies.

Typically, one imagines a black hole as sort of a gigantic cosmic pit that sucks in everything around it. But physicists say a new kind of space structure is possible that allows some information to escape black holes.

Previously, wormholes, theoretical structures predicted by the theory of general relativity (as Einstein-Rosen bridges), have been considered as possible ways to escape black holes. But the physics of such potential tunnels between locations in space-time never panned out. The wormholes would collapse immediately upon forming. So scientists theorized that may be some advanced civilization could find a technology, perhaps utilizing an exotic material to stabilize the wormholes. Basically, pure sci-fi.

But now, physicists proposed that a new type of wormhole is possible, called traversable. It would be be free of exotic material and could stay open on its own.

The work on traversable wormholes was carried out by Ping Gao and Daniel Jafferies of Harvard University and Aron Wall of Stanford University. According to their 2016 paper, a repulsive negative energy can be generated by a special quantum connection between the black holes on both sides of the wormhole. With the right kind of connection, something could go from being in one black hole into the other one.

If this kind of wormhole is possible, it means there could be interiors to black holes and that you could theoretically get out of one and live to tell about it.

Interestingly, the math involved in the work by the physicists on the wormholes is similar to the process called quantum teleportation, which can be demonstrated in a lab.

Here's how a traversable wormhole would work, in a graphic from Quanta Magazine:

In case you're wondering, traversable wormholes do not seem to function as time machines. Rather they support the concept of unitarity - that no information is ever lost. As John Preskill, a black hole expert from Caltech noted to Quanta Magazine, the new wormholes also protect “what we call ‘black hole complementarity,’ which means that the interior and exterior of the black hole are not really two different systems but rather two very different, complementary ways of looking at the same system."

Traversable wormholes were further explored in a recent paper co-authored by Juan Maldacena, Douglas Stanford, and Zhenbin Yang.

It bears noting that no actual wormholes have been discovered yet.

Article was published originally on BigThink.

SCIENTISTS are claiming to have created the first-ever "wormhole" - boosting hopes a portal that can transport matter light years across space could one day become reality. A wormhole is a theoretical space portal first identified by Albert Einstein that "can transfer matter through to another dimension." It is currently not even proven they actually exist, but a group of physicists have now claimed to have crafted a 'wormhole' that invisibly moves a magnetic field so it "appears to arrive out of nowhere".

Jordi Prat-Camps, a doctoral candidate in physics at the Autonomous University of Barcelona in Spain and co-author of a new study published in the journal Scientific Reports, said: "This device can transmit the magnetic field from one point in space to another point, through a path that is magnetically invisible. From a magnetic point of view, this device acts like a wormhole, as if the magnetic field was transferred through an extra special dimension. In 1935, Einstein and chis olleague Nathan Rosen discovered that the German-born physicist's famous theory of relativity "allowed for the existence of bridges that could link two different points in space-time."

The Einstein-Rosen bridges, or wormholes, could theoretically allow something to travel instantly between great distances. Although the new magnetic wormhole is not quite a space-time wormhole, as suggested by Einstein's theory, it is a realisation of a futuristic "invisibility cloak" first suggested as being possible in the journal Physical Review Letters in 2007.

The type of magnetic wormhole suggested in 2007 would hide electromagnetic waves from view from the outside. At the time it was concluded that to make it work would require materials that were extremely impractical to work with. However, new research has found that materials necessary to make a magnetic wormhole already exist and are easy to obtain. The team found superconductors, which can carry high current levels (charged particles), release magnetic field lines from within, thereby distorting them. From a magnetic point of view, this device acts like a wormhole, as if the magnetic field was transferred through an extra special dimension. Jordi Prat-Camps, a doctoral candidate in physics at the Autonomous University of Barcelona in Spain.

This enabled a magnetic field to act differently to its surrounding environment - and thereby the first step in hiding the magnetic field's usual disturbance. The scientists made an object of three layers - two concentric spheres and an interior spiral-cylinder - which transmitted a magnetic field from one end to the other when placed in a liquid-nitrogen bath, as high-temperature superconductors require the low temperatures of the liquid chemical to work.

The two outer layers then concealed the magnetic field's existence, making it "invisible" while in transit. Normally, the presence of the magnetic field should be detectable from all points around it. 

Mr Prat-Camps said: "From a magnetic point of view, you have the magnetic field from the magnet disappearing at one end of the wormhole and appearing again at the other end of the wormhole." 

The discovery could aid MRI scanning. Mr Prat-Camps said if a device could funnel a magnetic field from one spot to the other, it would be possible to take pictures of the body with the strong magnet placed far away, freeing people from the claustrophobic environment of an MRI machine.

Wormholes have long been considered to exist only in the realms of science fiction, but some physicists believe the theoretical portals could be real, and there could be one relatively close by. Wormholes, which were predicted by Einstein in his theory of General Relativity, are areas where space and time are bent to manipulate the distance.

It would take a huge mass to produce the manipulation of spacetime, and no natural examples have ever been found. However, experts from the International School for Advanced Studies in Trieste, Italy, say they are possible, and could be hiding within dark matter inside the Milky Way.

Professor Paulo Salucci, said: 

Scientists had believed any wormholes which exist in the universe could simply be the size of a pin prick. However, the team of astrophysicists say the one in our galaxy could be big enough to fit a spaceship which could traverse the cosmos, as they would likely exist in other spiral galaxies.

Prof Salucci, continued: 

The paper published in the Annals of Physics, read: "Our result is very important because it confirms the possible existence of wormholes in most of the spiral galaxies.