Time travel may seem like a far-fetched concept born out of a science fiction film, but an expert says the theory it exists isn't totally impossible.
Time travel, the idea a person can move through certain points in time, has gained momentum in recent years with photos containing unexplained details emerging online.
In 2018, a photo taken in 1943 in Newquay, Cornwall, showed people relaxing at Towan Beach.
A man in a brown suit was looking at something in his hands and it was speculated on Twitter he may have been looking at a mobile phone, despite the first handheld device not being invented until the 1970s.
While it seemed nothing more than a far-fetched theory, futurist Dr Richard Hames suggests time travel may not be completely out of the question.
"I think there is evidence that we might be able to travel in time because if you go by [Albert Einstein] in terms of science, the theory is the faster you go through space the slower you go through time – so you could claim that present day astronauts are time travellers," he told Yahoo News as part of its Conspiracies Unpacked series.
"But in terms of science fiction, then we're a long way short of that, being able to travel those distances over that amount of time."
However, Dr Hames said that time travel wasn't "completely impossible".
"If you look at the extraordinary literature around science fiction, it's amazing how often science fiction eventually becomes science fact," he said.
"What the best scientists in the world do is they play with ideas.
"So that is a possibility, I think it is plausible, yes, to go back in time."
Dr Hames said he does not believe people would have the capacity to travel into the future but there was scope to go into the past.
"But to go back in time also you'd need to be able to travel faster than the speed of light," he said.
Do parallel universes exist?
When talking about the grandfather paradox in terms of time travel, where a person couldn't exist if they travelled back in time and killed their grandfather before the conception of their parent, Dr Hames speculated there were instances where that could be possible.
"The only solution there of course is to use parallel universes where you could actually commit the event in one universe then travel to another universe to get back," he said.
"It's plausible in that sense."
Dr Hames said he wouldn't rule out the possibility of multiple universes.
"Whether we'll actually be ever able to prove that or use that is a different kettle of fish."
With so much unknown about our universe, Dr Hames said concepts like time travel could not be totally ruled out of theory.