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Sci-fi novels and movies are full of wacky ideas, most often as a springboard for an action-packed adventure rather than a serious attempt to predict future trends in science or technology. Some of the more common tropes, such as accelerating a spaceship to fantastic speeds in seconds without crushing occupants, are just not possible under the laws of physics as we understand them. Yet those same laws seem to allow other seemingly wacky sci-fi concepts, from wormholes to parallel universes. Here’s a look at some of the sci-fi ideas that could really be achieved – in theory, at least.
Wormholes
The idea of a wormhole – a shortcut through space that allows for almost instantaneous travel between distant parts of the universe – sounds like it was created as a fictional story pilot. But under its more formal name of the Einstein-Rosen Bridge, the concept existed as a serious theoretical concept long before science fiction writers got hold of it. It comes out of Albert Einstein‘s general relativity theory, what views gravity like a space-time distortion caused by massive objects. Together with physicist Nathan Rosen, Einstein theorized in 1935 that points of extremely strong gravity, such as black holes, could be directly connected to each other. And that’s how the idea of wormholes was born.
The forces around a black hole would destroy anyone who approached it, so the idea of traveling through a wormhole was not seriously considered until the 1980s, when astrophysicist Carl Sagan decided it was going to write a science fiction novel. According to BBC, Sagan encouraged fellow physicist Kip Thorne to find a feasible way to travel interstellar distances in a flash. Thorne duly devised a way – possible in theory, but highly unlikely in practice – for humans to travel interstellar through a wormhole unscathed. The result found its place in Sagan’s novel “Contact“(Simon and Schuster: 1985) which was later adapted into a film with Jodie Foster in the lead role.
While it is highly unlikely that wormholes will ever become the simple and convenient means of transportation depicted in the films, scientists have now come up with a more viable way to build a wormhole than Thorne’s original suggestion. It is also possible that, if wormholes already exist in the universe, they can be located using the new generation of gravitational wave detectors.
Chain drive
An essential prerequisite for most space adventure stories is the ability to get from A to B much faster than today. Aside from wormholes, there are several obstacles to achieving this with a conventional spacecraft. There is the enormous amount of fuel required, the overwhelming effects of acceleration, and the fact that the universe has a strictly enforced speed limit. This is the speed at which light travels – precisely a light year per year, which in a cosmic context is not very fast at all. Proxima Centauri, the second closest star to Earth, is 4.2 light years from the sun, while the center of the galaxy is 27,000 light years away.
Fortunately, there is a flaw in the cosmic speed limit: it only dictates the maximum speed at which we can travel. through space. As Einstein explained, space itself can be warped, so it may be possible to manipulate the space around a ship in a way that subverts the speed limit. The spacecraft would still travel through surrounding space at a speed slower than the speed of light, but space itself would move faster than that.
This is what the writers of “Star Trek” had in mind when they came up with the concept of “warp drive” in the 1960s. But to them, it was just a plausible sounding phrase, no real physics. It was not until 1994 that theorist Miguel Alcubierre found a solution to Einstein’s equations that produced a real distortion effect, the sister site of Live Science Space.com reported, by contracting the space in front of a spaceship and expanding it rearward. For starters, Alcubierre’s solution was no less invented than Thorne’s traversable wormhole, but scientists are trying to refine it in the hopes that it may one day be practical.
Time travel
The concept of the time machine is one of the great sci-fi plot devices, allowing characters to go back and change the course of the story – for better or for worse. But this inevitably raises logical paradoxes. In “Back to the Future”, for example, would Doc have built his time machine if he hadn’t been visited by the future Marty using that same machine? It is because of paradoxes like these that many people assume that time travel must be impossible in the real world – and yet, according to the laws of physics, it can really happen.
Just like with wormholes and spatial distortions, the physics that tell us it’s possible to time travel comes from Einstein’s general theory of relativity. It treats space and time as part of the same “space-time” continuum, the two being inextricably linked. Just like we talk about warping space with a wormhole or warp drive, time can also be warped. Sometimes it can be so distorted that it folds into itself, into what scientists call a “closed time curve“- although it could just as easily be called a time machine.
A conceptual design for such a time machine was published in 1974 by physicist Frank Tipler, according to physicist David Lewis Anderson, who describes research on the Anderson Institute, a private research laboratory. Called a Tipler cylinder, it must be large – at least 60 miles (97 kilometers) long, according to Humble – and extremely dense, with a total mass comparable to that of the sun. In order for it to function as a time machine, the cylinder must spin fast enough to warp spacetime to the point where time folds in on itself. It might not seem as simple as installing a flux capacitor in a DeLorean, but it does have the advantage that it really works, at least on paper.
Teleportation
The archetypal science fiction example of teleportation is the “Star Trek“ transporter, which, as the name suggests, is described simply as a convenient way to transport personnel from one place to another. But teleportation is quite different from any other form of transport: instead of the traveler moving through space from the starting point to the destination, teleportation results in the creation of an exact duplicate at the destination while the original is destroyed. Seen in these terms – and at the level of subatomic particles rather than human beings – teleportation is indeed possible, according to IBM.
The real world process is called quantum teleportation. This process copies the precise quantum state of a particle, such as a photon, to another that can be hundreds of miles away. Quantum teleportation destroys the quantum state of the first photon, so it looks like the photon was magically transported from one place to another. The trick is based on what Einstein called “spooky action at a distance”, but is more formally known as quantum entanglement. If the photon that is to be “teleported” is contacted with one of a pair of entangled photons and a measurement of the resulting state is sent to the receiving end – where the other entangled photon is located – then this last photon can be passed in the same state as the teleported photon.
It’s a complicated process, even for a single photon, and there is no way to adapt it to the type of instant transport system seen in “Star Trek”. Even so, quantum teleportation has important applications in the real world, such as hacker-proof communications and super-fast quantum computing.
Parallel universes
The universe is all our telescopes tell us – all the billions of galaxies extending outward from the big Bang. But is that all there is? The theory may not say: there could be a whole multiverse universe there. The idea of “parallel universes” is another familiar sci-fi theme, but when portrayed on screen, they usually differ from our own universe in only minor details. But the reality can be much stranger than that, with the basic parameters of physics in a parallel universe – such as the force of gravity or nuclear forces – different from ours. A classic depiction of a truly different universe like this, and the creatures that inhabit it, is Isaac Asimov’s novel “The Gods Themselves“(Double day: 1972).
The key to the modern understanding of parallel universes is the concept of “eternal inflation”. It represents the endless fabric of space in a state of perpetual and incredibly rapid expansion. Every once in a while, a localized point in this space – a self-contained Big Bang – comes out of the general expansion and begins to grow at a calmer rate, allowing material objects like stars and galaxies to form at the same time. interior. According to this theory, our universe is one of these regions, but there may be countless others.
As in Asimov’s story, these parallel universes could have completely different physical parameters from ours. At one time, scientists believed that only universes with virtually the same parameters as ours would be able to support life, but recent studies suggest that the situation may not be as restrictive as this, Previously reported live science. So there is still hope for Asimov’s aliens – but maybe not to come into contact with them, as happens in the novel. Nevertheless, traces of other universes could be detectable to us by other means. It has even been suggested that the mysterious “cold spot” in the cosmic microwave background is the scar of a collision with a parallel universe, wrote Ivan Baldry, professor of astrophysics at John Moores University in Liverpool at UK. The conversation.
Originally posted on Live Science.
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