According to Einstein's special theory of relativity, light traveling in a vacuum is the universal speed limit. But scientists love to try and break rules — and now a tweaked version of Einstein's equations suggests that faster-than-light travel might just be possible.
Albert Einstein's theory of special relativity was first published way back in 1905. It's a theory built on Galileo's suggestion that all uniform motion is relative — essentially that there can never be an absolute state of rest, because it's always possible to view a problem from a different frame of reference and see a stationary object as moving.
Einstein extended the theory well beyond Galileo's, and one crucial upshot was that the speed of light is the same for all inertial observers, regardless of where they are or how they're moving. In other words, the speed of light can't be broken.
Now, a team of scientists from the University of Adelaide has published a host of formulae that extend Einstein's work — and suggest that modified versions of his old equations predict that traveling beyond the speed of light is a theoretical possibility. The new work is based on all the same old principles used by Einstein, but they're extended to include a hypothetical infinite velocity.
Importantly, they've manged to extend the theory without recourse to exotic physics or imaginary masses, which is a favoured trick among physicists trying to sneak through a faster-than-light argument. Instead, they've approached the problem as mathematicians. James Hill, one of the researchers, explained to Cosmos:
"Essentially it sort of breaks the world up into two parts, we've got our Universe and then there is this place where everything is going faster than the speed of light and it could well be the key to understanding things like black holes and colliding galaxies."
In other words, the theory isn't suddenly going to see a host of Earth-bound experiments revealing particles that zip through the air faster than light. It could, however, begin to explain some of the complex physical phenomena we're yet to get a proper grip on — such as dark energy and black holes — because conventional laws of physics begin to break down there anyway.
It's worth remembering, though, that this is a new theory that hasn't been tested. Compared to Einstein's well-trodden work, which we know holds up to scrutiny, it's a precocious newcomer that still needs to prove itself.
Testing it out, though, may prove to be difficult. Speaking to Cosmos the theoretical physicist Craig Savage, who wasn't involved with the research, explained that "the theory doesn't say anything about the world as we know it." That in itself will make it difficult to test.
So physicists are faced with a new challenge: to work out if this theory is testable and then, if it is, to try and perform the experiments. "If the world it hypothesises exists," continues Savage, "then it seems to me the theory predicts some strange results for hypothetical faster-than-light physicists." The future of physics could just have gotten very, very interesting. [Proceeding of the Royal Society A]
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