Time machines similar to Dr Who’s Tardis are possible, Professor Brian Cox said in a speech at the British Science Festival.
“Can you build a time machine?” said Professor Cox. “The answer is yes.”
There’s just one, tiny problem, Professor Cox says - if you can build a machine capable of time-travel, you can only travel into the future. You can’t come back.
Professor Cox also suggested that research at the LHC might uncover extra dimensions - thus, perhaps finally explaining how the Tardis is bigger on the inside.
Professor Cox , a Dr Who fan, is to deliver a 60-minute speech on Dr Who to be screened by the BBC on November 23 - tackling questions such as extraterrestrial life, travelling to other dimensions and time travel.
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Professor Cox says that time travel is possible, and has already been done - albeit at a very small scale. The technology to accelerate something as big as a police box to near light speed does not yet exist.
Professor Cox says that, armed with such technology, “You can go into the future; you've got almost total freedom of movement in the future.”
To “travel” forward in time, you simply need to accelerate to speeds close to the speed of light, Cox says - as you get close to that speed, time slows down, but only for you, according to Einstein’s Theory of Special Relativity.
“If you go fast, your clock runs slow relative to people who are still. As you approach the speed of light, your clock runs so slow you could come back 10,000 years in the future," said Professor Cox.
Cox said previously on Conan O’Brien’s chat show that travel into the past was “impossible”, saying, “You can travel into the future as fast as you like. You can’t travel into the past.”
But in his speech in Birmingham, the physicist went into more detail - suggesting that “wormholes” often used in science fiction as portals through time may not offer a simple way to travel into the past.
“In General Relativity, you can do it in principle. It's to do with building these things called wormholes; shortcuts through space and time. But most physicists doubt it. Hawking came up with the 'chronology protection conjecture' - physics we don't yet understand that means wormholes are not stable.”
Travelling between different dimensions, though, might be easier - a relief for the Doctor, for whom “transdimensional engineering” was a key part of the Tardis.
Cox says, “We look for extra dimensions at the LHC (Large Hadron Collider). You can imagine extra dimensions in space, and that we are living on a sheet of higher dimensional space.”
Whether this explains how the interior of the Tardis is “dimensionally transcendental” - bigger on the inside - will perhaps be revealed in Cox’s speech on the 23rd.