Complex Made Simple

Back to the past – time travel is in our future?

Travel machines are being built and scientists say that soon you can get on board

It is all based on Einstein's special theory of relativity and the general theory of relativity Can you go back and be in a different location while time travelling? Each of us can have multiple histories that are inconsistent independently but become consistent as a whole

In the Back to the Future trilogy, Michael J. Fox as Marty McFly is a hero like figure travelling from present to past and back with ease.

At the time in 1990’s, the idea was amusing and for many far-fetched. 

And while you likely won’t be using the DMC DeLorean to travel between time zones that stretch decades or centuries, a few scientist are sure we will turn this into science and soon.

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Laser me up  

Astrophysicist Ron Mallett believes it is possible to travel in time, according to CNN travel.

He was inspired  by the book “The Time Machine by H.G. Wells” to build his prototype time travel machine.  

It is all based on Einstein’s special theory of relativity and the general theory of relativity which claims that gravity is actually the bending of space by a massive object. “If you can bend space, there’s a possibility of you twisting space,” Mallett told CNN travel.

“In Einstein’s theory, what we call space also involves time — that’s why it’s called space-time, whatever it is you do to space also happens to time.”

By twisting time into a loop, he suggests you could possibly travel from the future back to the past and then return to the future again.  He uses lasers to create a circulating beam of light that, he argues, could twist space and time.

His machine is also based around Albert Einstein’s theory of special relativity, which says that time accelerates or decelerates according to the speed at which an object is moving.

For example, if you were on a spacecraft traveling at the speed of light then the theory suggests time would be moving slower for you than people back on Earth.

If you were then to return to Earth having travelled in space for less than a week at this speed, Einstein theorizes that 10 years would have passed on Earth while you were gone.

Mallett is still looking for funding to conduct real-life trials on his machine.  

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Time travel in time only and not space? 

So here’s the age old question. Can you go back and be in a different location while time travelling?  

Albert Einstein’s theories don’t preclude time travel, but should it be possible, it will be travel in time only, not in space.

If you build a time machine and set the controls for six months in the future, in the meantime Earth will have rotated on its axis 182.5 times, and will have moved halfway around its orbit. The distance from Earth to the sun is about 150 million kilometres, so when you arrive six months in the future, Earth will be some 300 million kilometres away from you. Even if you set the dial for a year, you wouldn’t end up in the same place in space because the sun is in orbit around the galaxy.

Get it? Read it again and you will get it.  Travelling through time and remaining in the same location on Earth just isn’t possible.

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Multiple histories theory

One solution to travelling into the past exists using ‘multiple histories’.

Each of us can have multiple histories that are inconsistent independently but become consistent as a whole, and this way changing something in the past to affect the future is now possible.

Dr Barak Shoshany a researcher at the institute told “We show, using a concrete model, that multiple histories can in fact resolve time travel paradoxes.”

Dr Shoshany and his student Jacob Hauser of Pomona College describe a model in which a person could theoretically travel from one timeline to another by stepping through a hole in space-time, or wormhole, in a way that they claim is “mathematically possible”.

He added: “The parallel universes approach we suggest says there are different parallel universes where things are roughly the same, and each one is mathematically on a separate space-time manifold.

“You can go between those manifolds when you travel back in time.”

Multiple timelines would allow you to travel to a different timeline and kill your grandparents without causing a paradox.

Stephen Hawking’s Hawking Conjecture suggests time travel is impossible, commonly considered the orthodox opinion.

Another approach is called the Novikov Conjecture, which describes “only one history”.

Dr Shoshany said: “A way to understand this is if you went back in time, then this already happened and anything that you might have changed has already changed.

“So if you go back and try to kill your grandpa, your gun is not going to work or it misses.

“This is because if you did kill your grandfather that would be inconsistent.”