TRAVELLING through time may not be a fantasy explored solely in the world of science fiction as most theoretical physicists agree that it is possible.
But while we all know that we can move forward in time (it’s happening right now), most experts agree that it is not possible to move backwards and visit the past.
Is time travel possible?
Theoretical physicists such as Professor Steve Hawking and Professor Brian Cox believe that travelling at the speed of light could propel humans into the future.
This is based on the Albert Einstein's Theory of Special Relatively, published in 1905, in which an object moving at the speed of light would experience time slowing down.
This would mean that while the person moving fast would see their clock slowing down, time would stay the same for people who were moving normally.
The most obvious problem with this theory is figuring out how to propel a human at the speed of light without killing them.
The boffins at CERN in Switzerland have propelled tiny particles at the speed of light using the Large Hadron Collider – but are a long way off strapping humans into a similar kind of machine.
Another theory is using wormholes to transport humans from one point in space to another instantly.
This idea was theorized in 1916 and was again developed from Einstein's groundbreaking relatively theory.
Kip Thorne, renowned theoretical physicist at California Institute of Technology (Caltech), further developed the wormhole theory in the 1980s.
Thorne, who exec-produced mind-bending time-travel blockbuster Interstellar, believes that humans in the future would have to construct their own wormholes in order to travel through them.
This is because wormholes would evaporate before anything, even light, could pass from one opening to another.
He ultimately believes that while potentially possible, humans would never have the resources or engineering know-how to time travel through these cosmic tunnels, reports Space.com.
What the experts say?
Prof Stephen Hawking: “Time travel was once considered scientific heresy. I used to avoid talking about it for fear of being labelled a crank. But these days I’m not so cautious. In fact, I am obsessed by time.”
Prof Brian Cox: “Time travel into the future is possible. In fact, it’s an intrinsic part of the way the universe is built. We’re all time travellers in our own small way.”
Prof Ronald Mallett: “Depending on breakthroughs, technology and funding, I believe human time travel could happen this century,” says the Professor of Physics at the University of Connecticut in the US.
What have alleged time travellers claimed recently?
A viral clip shows a man, who claims he travelled to the year 2118, brandishing a blurred photograph which he says proves his ridiculous story.
Alexander Smith has told how he made frequent trips back and forth in time as part of a "top secret" CIA mission in 1981.
The snap he claims to have shot while "visiting" 2118 appears to be of a futuristic city.
Speaking to Apex TV, he said: There are many threats to the human race. The number one threat to humanity as we know it is global warming, rising sea levels as well as the increase in Co2 in our atmosphere.
“We must take steps now to combat global warming."
The alleged former CIA man also revealed that when the aliens arrive, they will visit the world’s top officials.
He added: “Aliens do visit us, there are intelligent extra-terrestrials that do come to Earth, this is in the mid 21st century.
“There is actually contact with intelligent extra-terrestrials long before it was revealed to the public.
“These aliens don’t necessarily live among us but they do visit from time to time.”
Another viral video features a man who claims he's from the year 2030 and who says he had passed a lie detector test.
The self-styled time-traveller, who calls himself Noah, begged to stay anonymous claiming he could be assassinated for revealing what the future holds.
Among his claims are that Donald Trump gets re-elected in 2020, there will be a revolution in Artificial Intelligence and powerful computers will be worn like Google-style glasses.
Fearing people would be sceptical he agreed to take a lie-detector test – although the machine testing him is never shown on screen.