It may be possible to travel through a wormhole and send a signal back. Models of hypothetical wormholes 鈥� bridges that create a shortcut between two distant locations in space-time 鈥� have shown that they are extremely fragile and liable to implode if anything falls in, but a pulse of light may be able to outrace that collapse.
at the College of the Holy Cross in Massachusetts and two of his students simulated a traversable wormhole to examine what would happen when matter entered it. They found that dropping normal matter in would make the wormhole rapidly collapse, but not so fast that you couldn鈥檛, in theory, send a message home first.
The type of wormhole they simulated is held open by an exotic type of theoretical matter called ghost matter, which has negative energy. There is some evidence that very small amounts of negative energy can be created through quantum effects, but the idea that there could ever be enough to make a wormhole is still extremely speculative.
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鈥淲e simply put a negative sign in front of the energy. From a physical standpoint this may be completely ridiculous; such matter may have no relationship with reality,鈥� says Kain. 鈥淏ut we鈥檙e just trying to figure out what a wormhole might look like and how we might simulate it 鈥� wormholes are hypothetical to begin with, so using hypothetical matter maybe isn鈥檛 the biggest stretch.鈥� The negative energy is required in the simulations to make the wormhole traversable.
鈥淭his is at the boundary of what is science and what is not 鈥� it does not violate the laws of physics, but it probably will not be able to be realised anytime soon,鈥� says at the Michoacan University of Saint Nicholas of Hidalgo in Mexico. 鈥淚t鈥檚 sort of the twilight zone of science.鈥�
Nevertheless, he says, simulating speculative objects like these wormholes could help us understand extreme space-time phenomena that are more likely to exist.
This particular kind of wormhole wouldn鈥檛 look like more traditional wormholes with black holes at either end. 鈥淚t would look just like the space around it,鈥� says Kain. But add in a little regular matter, and the bridge would begin to narrow and then close, and the entries at either end would collapse and become two distinct black holes.
While this process would be fast, it wouldn鈥檛 be instantaneous. 鈥淲e don鈥檛 see a way that you could return after going through it, but you could get a signal back to your friends,鈥� he says. This means that one could hypothetically send a probe through this kind of wormhole to learn something about the other side 鈥� although in the simulations, not all of the matter made it through the wormhole, so it鈥檚 unclear whether the probe would make it in one piece.
Unfortunately, the fact that this type of wormhole would collapse when any matter fell in also means that it would be extraordinarily difficult to maintain one for any reasonable amount of time.
鈥淪ure, once one of these wormholes forms, a signal could go through, but there鈥檚 still a question of how you could form one in the first place,鈥� says , also at the Michoacan University of Saint Nicholas of Hidalgo in Mexico. 鈥淭hey are very unstable, so they would be very difficult to construct.鈥�
The next step, says Kain, is to apply similar methods to studying more plausible types of wormholes and see what we can learn from them about the mechanics of space-time.
Physical Review D
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