In science fiction, wormholes are often used to travel long distances in space. Are these magical bridges possible in reality?
With all the enthusiasm, the future of humanity in space (here by space does not mean the solar system and not even the galaxy) looks hazy. We are bags of meat and water, there is still more water, and the stars are very, very far away. Armed with the most optimistic spaceflight technology imaginable, reaching another star in a lifetime is unlikely to succeed.
Reality tells us that even the closest stars are inconceivably far away, and it will take a huge amount of energy and time to make the journey. Reality says that we need a ship that somehow can survive for hundreds or thousands of years, during which generations and generations of astronauts will be born, live their lives and die on the way to another star.
Science fiction, on the other hand, teases us with seductive techniques of advanced movement. Turn your warp drive on and watch the stars fly by, and the journey to Alpha Centauri is like a cruise.
It's even easier to take a wormhole. A magic bridge connecting two points in space and time with each other. Just determine your destination, wait for the stargate to stabilize and move. Move to a place half a galaxy away from you.
It would be nice. Someone must definitely invent these wormholes, paving - no, cutting - a path for us into a brave new future of intergalactic travel. Where did these wormholes come from and why are we still not using them?
A wormhole, also known as the Einstein-Rosen bridge, is a theoretical method of piercing space and time so that two points in space can be connected together. And then move instantly from one to another.
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A classic example of a wormhole demonstration was shown in the movie Interstellar: you draw two dots on paper, then fold the paper and pierce both dots with a pencil. Ok, everything is clear on paper, but what about physics?
Einstein showed that gravity is not a force that attracts matter like magnetism, but rather bends spacetime. The moon thinks it is moving in a straight line through space, but is actually following a curved path created by Earth's gravity.
Albert Einstein and physicist Nathan Rosen decided that it was possible to confuse spacetime so closely that two points would share the same physical location. If you then manage to stabilize the whole thing, you can carefully separate the two regions of space-time so that they are in the same place, but at any distance from each other.
Dive into the gravity well on one side of the wormhole and instantly find yourself on the other side. Millions or billions of light years away. And while wormholes are theoretically perfectly possible to create, in practice, from what we know at the moment, it is almost impossible.
The first major problem is that wormholes are impassable according to general relativity. Think about it: the physics that predicts these things doesn't allow them to be used as a method of transportation. This is a strong argument against them.
Second, even if it is possible to create wormholes, they will be completely unstable and collapse immediately after formation. If you try to walk one way, you can easily end up in a black hole.
Third, even if they are passable and stable, the attempt of any material to pass through them - even photons of light - can lead to collapse.
However, there is a glimmer of hope, as physicists have not fully figured out how to combine gravity and quantum mechanics.
This means that the universe itself can hide facts about wormholes that we do not yet understand. The possibility exists that they emerged naturally as part of the Big Bang, when the spacetime of the entire universe was entangled in a singularity.
Astronomers suggested looking for wormholes in space by observing how their gravity distorts the light of the stars behind them. But so far nothing has been found.
There is also the possibility that wormholes appear naturally, like the virtual particles we know exist. Only they will be extremely small, on a Planck scale. You will need a small spacecraft.
One of the most fascinating consequences of wormholes is that they can be used for time travel.
This is how it works. First, create a wormhole in the lab. Then take one end of the wormhole, place it on the spacecraft and fly at close to light speed so that the time dilation effect works.
For humans, only a few years will pass on a spaceship, while hundreds or even thousands of years will pass on Earth. If you can manage to keep the wormhole stable, open, and walkable, it would be very interesting to travel through it.
If you walk in one direction, you will not only cover the distance between the wormholes, but you will also travel from one time to another. Moreover, it should work in both directions, back and forth. Some physicists, like Leonard Susskind, think that this will not work because it violates two fundamental principles of physics: conservation of local energy and the energy-time uncertainty principle.
Unfortunately, it seems like wormholes should remain in science fiction for the foreseeable future, and perhaps forever. Even if the opportunity arises to create a wormhole, it will have to be kept stable and open, and how to prevent the matter in it from collapsing. However, if we ever accomplish this feat, the issue of travel in space will be resolved.
