Einstein Said along with Your Science Teacher We CanNot Go to Light Speed } XNo More!
(Copyright: Science Photo Library)
Einstein said it is impossible, but as Jennifer Ouellette explains some scientists are still trying to break the cosmic speed limit – even if it means bending the laws of physics.
OPERA’s calibration error dashed those hopes, but there are still plenty of potential loopholes to be explored, such as the Star Trek-inspired warp drive mechanism first proposed by Mexican physicist Miguel Alcubierre in 1994. In general relativity, spacetime is dynamic, not static, warping and bending in response to the presence of mass or energy. Alcubierre suggested that it might be possible to encase a spaceship within a “warp bubble”, whereby space contracted in front of the craft and expanded behind it, enabling it to travel faster than light. But within that bubble, spacetime would remain essentially flat and the craft would technically “obey” the cosmic speed limit.
Alas, once again we face an energy problem: achieving that degree of curvature would require enormous amounts of energy – and negative energy at that – equivalent to the mass of Jupiter. To propel a spacecraft across the Milky Way galaxy may require more energy than can be found in the mass of the entire universe. A more energy-efficient ring-shaped design for such a warp drive was described recently at a symposium on interstellar space flight, offering a meager shred of hope to diehard space acolytes that for future generations, warp drive will be a reality.
However, given what we know about general relativity and quantum field theory, “It almost certainly can’t be done,” says Ken Olum, a cosmologist at Tufts. “Of course, if we are talking about quantum gravity, it’s hard to know, because we don’t really know what that is.”
Former Nasa scientist Kevin Grazier, who was the technical consultant for Battlestar Galactica, says that a version of the Alcubierre warp drive inspired the “jump drive” used in that series. It was based on the assumption that, in this fictional world, the Colonials had merged theories of electromagnetism and gravity, such that if you could create a very intense electromagnetic field, it would be functionally equivalent to an intense gravitational field capable of warping spacetime. Turning that ingenious fiction into a viable reality is another matter altogether.
Brane gain
If we really want to get speculative, Olum suggests FTL travel would be possible if exotic concepts, like those that emerge from superstring theory, prove to be correct.
We inhabit four-dimensional spacetime, but various permutations of superstring theory suggest our universe is just one of many, co-existing within a bubble of five-dimensional spacetime called the “bulk.” Within that bulk, our universe lines up in parallel with all the others, just like the pages in a book. Olum explains that, hypothetically, one could take a shortcut through the bulk, thereby arriving at your destination sooner than if you had travelled along your four-dimensional surface, or brane (short for membrane) as it is known.
Even then, there is a catch. “In brane theories, only gravitons can travel through the bulk,” says Olum. So one would need to invent a machine that could scan an object and transmit the information in the form of gravitons to a second machine on the other end which would then reconstruct that object – shades of teleportation, only with gravitons.
Considering we have yet to observe gravitons in our most powerful accelerators, and the current record for teleporting small clouds of atoms is the relatively non-Cylon-troubling distance of 143 kilometres (88 miles), this scenario must also remain firmly in the realm of science fiction, at least for now. Science advances, but it does so slowly, at a pace nowhere near the speed of light.
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