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Our everyday experience of interstellar travel usually comes in the shape of the U.S.S. Enterprise zooming around the galaxy at warp speed. Unfortunately, the warp drive is primarily used as a tool by scriptwriters to condense the extreme interstellar distances into hour-long episodes. But there's a growing field of study that actually attaches some physics -- albeit rather "exotic" physics -- to superluminal (a.k.a. faster-than-light) travel.
Earlier this month, scientists and engineers were able to discuss their warp drive concepts at the 100 Year Starship Symposium in Houston, Texas, and there was some good news for sci-fi fans everywhere: the warp drive might not be as energy hungry as previous studies suggested.
Sonny White of NASA's Johnson Space Center presented his calculations on the energies required to travel faster than Einstein's famous speed limit: the speed of light. By White's reckoning, his design of starship -- that is "adjusted into more of a rounded doughnut, as opposed to a flat ring" and oscillates the warp intensity -- could be powered by the approximate mass-energy of the Voyager 1 space probe.
Although "the mass-energy of the Voyager 1 space probe" may not sound like much, if you convert the 722 kilogram Voyager mass into raw energy (using Einstein's famous mass-energy equivalence equation: E=mc2), White's warp drive would require 6.5x1019 Joules (65 exajoules) to create a warp bubble. That's nearly the entire annual energy consumption of the United States.
Clearly, this monstrous energy requirement isn't practical, but it's one heck of an improvement over previous estimates.
A Universe Of Energy
In 1994, physicist Miguel Alcubierre was widely credited to be the first to put some real physics into the warp drive. Although Star Trek would have us believe that you just need some dilithium crystals and a starship captain to point his finger, saying "Engage," Alcubierre discovered that the warp drive was theoretically possible, but it would need all the energy in the entire universe to function.
Alcubierre realized that for a spacecraft to travel faster than the speed of light -- something that Einstein's Special Theory of Relativity prohibits -- the spacecraft would need to somehow create a warp "bubble" around it. This would allow the spacecraft to be contained within its own region of spacetime. If the bubble can be controlled, then the light-speed limit can be exceeded in 'normal' space -- the spacecraft itself would be stationary whereas the bubble in spacetime will zip around at, effectively, infinite speed.
As described by Eric W. Davis, senior research physicist at the Institute of Advanced Studies in Austin, Texas, and co-author of Frontiers of Propulsion Science, the warp drive can be envisaged as a means of "surfing" through spacetime:
"Think of space as the ocean and Michael Phelps is a starship. He's propelled by fission or fusion rockets -- any kind of rocket -- but he's swimming vigorously, leaving planet Earth and he's going to swim all the way to Alpha Centauri, 4.3 light-years away. He's flailing his arms, kicking his feet, expending a great deal of energy and he can't go very fast ... the resistance of the ocean water is going to keep him limited to below the speed of light. Einstein's special theory says you can't go faster than light, you can't even reach it, but you can always stay less than (light-speed). Warp drive is a whole different matter. What you do is use "exotic energy" ... basically just a fancy word for vacuum energy. You're going to use some quantum energy from the vacuum and you're going to surround your starship with a bubble of this energy and it bends space -- it creates a surf effect. Michael Phelps is now standing on a surfboard and instead of swimming through space at less than the speed of light, he's surfing on space. Space is like the wave on the ocean water that surfs him to the beach faster than the speed of light." -- Eric Davis on "Attack of the Show" (video below)
Fill 'er Up with One Jupiter
Although Alcubierre's calculations showed that unimaginably huge amounts of energy would be needed to create this warp bubble, recently, Richard Obousy, co-founder and president of Icarus Interstellar (a key partner of the 100YSS), used our new understandings of quantum mechanics and applied them to the warp drive.
Obousy's approach is to manipulate dark energy -- the mysterious force that appears to permeate the entire Universe, causing it to expand -- in such a way that extra dimensions (as predicted by string theory) can facilitate the creation of a bubble of spacetime.
"Given that extra dimensions have not yet experimentally been shown to exist, and the idea that dark energy is an artifact of these extra dimensions is somehow related to these dimensions is clearly highly theoretical," Obousy told Discovery News, "however it provides us with an interesting perspective from which to examine the problem."
Although this method would theoretically allow a Alcubierre-like solution to traveling faster than the speed of light, vast amounts of energy would still be needed -- the approximate mass-energy of Jupiter no less -- but at least it's an improvement from the "all the energy in the Universe" solution.
Referring to White's work, Obousy continued: "The Jupiter calculation was purposefully created as an 'upper bound' to the problem, and I'm glad that the work performed by my colleagues has demonstrated ways to reduce the energy requirements down further."
The upshot is that the energy requirement for the warp drive is decreasing, albeit theoretically. With the help of quantum mechanics, we've seen a massive reduction in the amount of energy needed. And now, with White's tweak of warpship design, the energy has been reduced by many orders of magnitude. But the biggest news of all is that White and his NASA team are designing laboratory experiments that will, hopefully, form the foundations for a practical solution to building a warp drive.
"The findings I presented today change it from impractical to plausible and worth further investigation," White told SPACE.com's Clara Moskowitz at 100YSS. "The additional energy reduction realized by oscillating the bubble intensity is an interesting conjecture that we will enjoy looking at in the lab."
And as pointed out by Davis in the video below, there's no predicting when the next big physics breakthrough will happen, potentially aiding warp drive studies.
"Disruptive innovations are not predictable, they can pop up at any time between now and 200 years from now ... we could have warp drive within our lifetime," Davis said. "We just can't predict when some genius is sitting somewhere and a lightbulb goes off over his head and he figures out an innovation which can overcome this problem of producing negative energy in large enough quantities."
So the next time someone tells you that the warp drive is "impossible," just tell them that real science is being applied to warping spacetime, NASA is even trying to replicate some of the warping effects with lasers in the lab and, besides, we never know what breakthroughs are just around the corner.
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Until now, there has been little idea about what a spaceship propelled by a warp drive (or a warpship) would look like. Would it resemble the sleek Starship Enterprise? Or will it be like nothing we've seen before?
After speaking with Dr. Richard Obousy, he shared his concept for a futuristic, yet scientifically accurate, warpship design.
The physics behind the warpship is purely theoretical, however. 'Dark energy' needs to be understood and harnessed, plus vast amounts of energy needs to be generated, meaning the warpship is a technology that could only be conceived in the far future. That said, Dr. Obousy's warpship design uses our current knowledge of spacetime and superstring theory to arrive at this futuristic concept.
So here's your exclusive look at what could be the future warp drive propulsion...
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The physics behind the warp drive is, as you'd expect, complex. However, it is hoped that in the future mankind will learn how to harness 'dark energy', an energy that is theorized to permeate through the entire universe. Cosmologists are particularly interested in dark energy as it is most commonly associated with the observed expansion of the universe.
Immediately after the Big Bang, some 13.73 billion years ago, the universe expanded faster than the speed of light, an event called universal inflation. Dark energy (which still has experts baffled as to what it actually is) is theorized to have driven this expansion, and it continues to this day. Much like the 2-dimensional surface of a balloon stretching when being inflated, 3-dimensional space is stretching, propelling the galaxies away from one another.
If an advanced technology could harness this dark energy, a warpship could possibly manipulate the spacetime surrounding it. According to Dr. Obousy, the extra dimensions as predicted by superstring theory could be shrunk and expanded by the warp drive through manipulation of local dark energy. At the front of the warpship spacetime would be compressed, and it would expand behind.
"You can apply the analogy of a surfer riding a 'wave' of spacetime," Dr. Obousy told Discovery Space. This 'wave' would facilitate faster-than-light-speed propulsion without breaking any laws of physics.
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The shape of the warpship was chosen to optimize the manipulation of surrounding dark energy, creating a spacetime bubble. How exactly the bubble would be created is still a mystery. But once the bubble gets created, spacetime at the front of the warpship would be compressed, and behind, it would expand. Inside the bubble, spacetime remains unchanged; therefore the warpship floats in the center of stationary space while the bubble moves through spacetime.
The bubble itself, containing the warpship, "drives the spacecraft forwards at arbitrarily high speeds," said Obousy. This means the warpship can travel faster than the speed of light.
To initiate the warp drive, however, vast amounts of energy would be required. Also, there will be some practical issues to overcome, such as preventing the creation of artificial black holes, as well as catastrophic warp bubble collapse when the power is switched off.
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This graphic demonstrates how the warpship would effectively be "surfing" on a spacetime wave to achieve faster-than-light-speed travel.
Quelle: DiscoveryNews
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