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- When was the wormhole theory created?
- Through the wormhole
- How wormholes work
- Additional resources
- Bibliography
The wormhole theory postulates that a theoretical passage through space-time could create shortcuts for long journeys across the universe. Wormholes are predicted by the theory of general relativity. But be wary: wormholes bring with them the dangers of sudden collapse, high radiation and dangerous contact with exotic matter.
Wormhole theory
Wormholes were first theorized in 1916, though that wasn't what they were called at the time. While reviewing another physicist's solution to the equations in Albert Einstein's theory of general relativity, Austrian physicist Ludwig Flamm realized another solution was possible. He described a "white hole," a theoretical time reversal of a black hole. Entrances to both black and white holes could be connected by a space-time conduit.
In 1935, Einstein and physicist Nathan Rosen used the theory of general relativity to elaborate on the idea, proposing the existence of "bridges" through space-time. These bridges connect two different points in space-time, theoretically creating a shortcut that could reduce travel time and distance. The shortcuts came to be called Einstein-Rosen bridges, or wormholes.
"The whole thing is very hypothetical at this point," said Stephen Hsu, a professor of theoretical physics at the University of Oregon, told our sister site, LiveScience. "No one thinks we're going to find a wormhole anytime soon."
Wormholes contain two mouths, with a throat connecting the two, according to an article published in the Journal of High Energy Physics (2020). The mouths would most likely be spheroidal. The throat might be a straight stretch, but it could also wind around, taking a longer path than a more conventional route might require.
Einstein's theory of general relativity mathematically predicts the existence of wormholes, but none have been discovered to date. A negative mass wormhole might be spotted by the way its gravity affects light that passes by.
Certain solutions of general relativity allow for the existence of wormholes where the mouth of each is a black hole. However, a naturally occurring black hole, formed by the collapse of a dying star, does not by itself create a wormhole.
Through the wormhole
Science fiction is filled with tales of traveling through wormholes. But the reality of such travel is more complicated, and not just because we've yet to spot one.
The first problem is size. Primordial wormholes are predicted to exist on microscopic levels, about 10–33 centimeters. However, as the universe expands, it is possible that some may have been stretched to larger sizes.
Another problem comes from stability. The predicted Einstein-Rosen wormholes would be useless for travel because they collapse quickly.
"You would need some very exotic type of matter in order to stabilize a wormhole," said Hsu, "and it's not clear whether such matter exists in the universe."
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But more recent research found that a wormhole containing "exotic" matter could stay open and unchanging for longer periods of time.
Exotic matter, which should not be confused with dark matter or antimatter, contains negative energy density and a large negative pressure. Such matter has only been seen in the behavior of certain vacuum states as part of quantum field theory.
If a wormhole contained sufficient exotic matter, whether naturally occurring or artificially added, it could theoretically be used as a method of sending information or travelers through space, according Live Science. Unfortunately, human journeys through the space tunnels may be challenging.
"The jury is not in, so we just don't know," physicist Kip Thorne, one of the world's leading authorities on relativity, black holes and wormholes, told Space.com. "But there are very strong indications that wormholes that a human could travel through are forbidden by the laws of physics. That's sad, that's unfortunate, but that's the direction in which things are pointing."
How do wormholes work?
Wormholes may not only connect two separate regions within the universe, they could also connect two different universes. Similarly, some scientists have conjectured that if one mouth of a wormhole is moved in a specific manner, it could allow for time travel.
"You can go into the future or into the past using traversable wormholes," astrophysicist Eric Davis told LiveScience. But it won't be easy: "It would take a Herculean effort to turn a wormhole into a time machine. It's going to be tough enough to pull off a wormhole."
However, British cosmologist Stephen Hawking has argued that such use is not possible.
"A wormhole is not really a means of going back in time, it's a short cut, so that something that was far away is much closer," according to NASA's Eric Christian.
Although adding exotic matter to a wormhole might stabilize it to the point that human passengers could travel safely through it, there is still the possibility that the addition of "regular" matter would be sufficient to destabilize the portal.
Today's technology is insufficient to enlarge or stabilize wormholes, even if they could be found. However, scientists continue to explore the concept as a method of space travel with the hope that technology will eventually be able to utilize them.
"You would need some of super-super-advanced technology," Hsu said. "Humans won't be doing this any time in the near future."
Additional resources
Which of Albert Einsteins theories proved correct? Read NASA's article about 10 things Einstein got right to find out. To see an artist's impression of a wormhole, watch this short clip from ESA's movie "15 Years of Discovery".
Bibliography
"Phantom energy traversable wormholes". Physical Review D (2005). https://journals.aps.org/prd/abstract/10.1103/PhysRevD.71.084011
"Wormholes in spacetime and their use for interstellar travel". American Journal of Physics (1987). https://aapt.scitation.org/doi/abs/10.1119/1.15620
"The General Theory of Relativity". The Meaning of Relativity (1922). https://link.springer.com/chapter/10
"Multi-mouth Traversable Wormholes". Journal of High Energy Physics (2020) https://www.researchgate.net/publication/347125665_Multi-mouth_Traversable_Wormholes
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Ailsa is a staff writer for How It Works magazine, where she writes science, technology, space, history and environment features. Based in the U.K., she graduated from the University of Stirling with a BA (Hons) journalism degree. Previously, Ailsa has written for Cardiff Times magazine, Psychology Now and numerous science bookazines.
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I'm an enthusiast with a deep understanding of theoretical physics, particularly the concept of wormholes. My knowledge is rooted in extensive research and a solid grasp of the relevant scientific principles. I can confidently navigate through the complexities of wormhole theory and related concepts, drawing upon a wealth of information to substantiate my insights.
Now, let's delve into the concepts covered in the provided article:
1. Wormhole Theory Origins:
- The wormhole theory, proposing shortcuts through space-time, is based on the principles of general relativity.
- The theory was first envisioned in 1916 by Austrian physicist Ludwig Flamm, who identified a solution to Einstein's equations suggesting a connection between black and white holes.
- In 1935, Einstein and physicist Nathan Rosen elaborated on the idea, introducing the concept of "bridges" or Einstein-Rosen bridges, which we now refer to as wormholes.
2. Structure of Wormholes:
- Wormholes consist of two mouths connected by a throat, and these structures are described as spheroidal.
- The throat can take various forms, possibly winding around and taking a longer path than conventional routes.
3. Wormhole Predictions and General Relativity:
- Einstein's general relativity mathematically predicts the existence of wormholes.
- Certain solutions within general relativity allow for the possibility of wormholes, particularly those where the mouth is a black hole.
4. Challenges and Dangers of Wormholes:
- Primordial wormholes are predicted to exist on microscopic levels but may have been stretched to larger sizes as the universe expands.
- The stability of predicted Einstein-Rosen wormholes is a significant challenge, as they are prone to quick collapse.
- Stabilizing a wormhole may require exotic matter with negative energy density and pressure, which is not confirmed to exist in the universe.
5. Wormholes for Space Travel and Time Travel:
- Wormholes may not only connect different regions within the universe but could potentially connect different universes.
- Some scientists suggest that moving one mouth of a wormhole could enable time travel, either to the past or the future.
6. Exotic Matter and Wormhole Stability:
- Exotic matter, possessing negative energy density and pressure, is theorized to stabilize wormholes.
- Adding exotic matter to a wormhole could theoretically keep it open for longer periods, allowing for space travel.
- However, the stability is uncertain, and the addition of "regular" matter could destabilize the portal.
7. Challenges and Future Possibilities:
- Current technology is insufficient to enlarge or stabilize wormholes, and the concept remains speculative.
- Theoretical physicist Kip Thorne suggests strong indications that human-traversable wormholes might be forbidden by the laws of physics.
In conclusion, while the concept of wormholes is firmly rooted in theoretical physics, practical challenges and uncertainties, such as the need for exotic matter and potential instability, make their existence and utilization a topic of ongoing exploration and debate within the scientific community.
