Space and time physics
Wormholes: secret tunnels in the air, real or mathematical
Imagine the two ends of a piece of paper being thousands of miles apart, but if the paper is folded, there's only one finger at the end -- the wormhole, which is the fold of the universe。
In countless science-fiction films, interstellar spacecraft drilled into wormholes, passing from one end of the galaxy to the other. This fascinating concept, is it just a science fiction writer, or a real physics prophecy? The answer is exciting: the wormhole is a legitimate solution to a broad relativity equation — it may exist in mathematics. But there's a huge gap between "mathematics may" and "realism."。
Einstein and wormhole were born
In 1935, einstein and his student natan rosen, while studying the interpretation of general relativism, discovered a strange temporal and temporal structure: two black holes could be connected by a "throw" to form a time and space tunnel. This structure is known as the einstein-roson bridge, the name of the wormhole that we call today, officially introduced by physicist john wheeler in 1957。
The broad relativity describes the curves of time and space: mass and energy can cause time and space to curvature. A very high-mass object bends the surrounding space-time depth, while theoretically, the two extremely bent space-time "throats" can be connected to each other, forming a shortcut to close to zero the distance between the two distant points。
Intuitive interpretation:
Imagine the universe as a giant rubber film. Normally, there must be a long journey along the membranes from point a to point b. But if you can fold the membrane, get a and b on the other side of the membrane, then you can put a hole through the past -- the shortcut is the wormhole. The distance hasn't changed, but the road has changed。
Why does the wormhole collapse suddenly
However, the einstein-rosen bridge has a fatal flaw — it is extremely unstable. According to a broad relativism calculation, this primitive wormhole collapses at the moment of formation, and there is not enough time for any substance or signal to travel. It is not a truly accessible tunnel, but rather a door that opens and closes immediately。
This raises a key question: is there any way to open a wormhole and keep it open for long enough? The theoretical answer is "negative energy" material, also called "exotic matter"。
Negative energy: the magic of a wormhole
In 1988, the physicist kip thorne (the nobel prize laureate for physics in 2017) and mike morris presented the "passable wormhole" model, maurice-sorn wormhole. They have demonstrated that if there are substances with negative energy density, it is in principle possible to stabilize the throat of the wormhole, keep it open and allow objects to cross。
Interestingly, negative energy is not a mere fantasy. The kasimir effect in quantum mechanics proves that between two very close parallel metal plates, a vacuum zero can produce negative energy densities. This is the real thing that can be measured in the laboratory. But the negative levels of energy that humans can control today are countless orders of magnitude different from what is needed to build a wormhole。
Wormholes are temptingly associated with time travel
Even more dazzling is the theoretical achievement of time travel in the wormhole. Thorne points out that if the wormhole is in a different gravitational environment on both ends or moves at different speeds (relativity effects can lead to different time flow speeds), the traveler across the wormhole will "time travel"-- – not only is there space that cuts across the universe, but there may be a return to the past or to the future。
This immediately triggered a troubling "grandfather paradox": if you go back through the wormhole and stop your grandfather from meeting your grandmother, you will not be born. How can you cross back? To that end, hawking put forward a "time-sequenced conservation assumption" that there was a mechanism in nature that would destroy wormholes with quantum effects, thereby preventing the cause and effect of the violation。
Er= epr conjecture:
In 2013, physicists mardasena and saskind raised the striking assumption that wormholes (einstein-rosen bridge, er) and quantum entanglements (einstein-podorski-rosen, epr) may be different descriptions of the same thing. Each pair of quantum entanglement particles may be connected through a wormhole. The geometry of time and space may have been woven by quantum tangles。
The wormhole has not been observed yet, but it's not just a science fiction patent. It is one of the most fascinating puzzles at the intersection of broad relativity and quantum mechanics. As the theory of gravitational wave astronomy and quantum gravity progresses, perhaps one day we can really find evidence of space and time in the universe. It will be the most exciting moment in the history of human awareness。
Interactive topics
If the wormhole is real, what do you want to do with it
It's going across the universe
Go back to the past and change something
To explore the secrets of parallel universes
There can be no wormhole
