Whatever the case, that doesn't stop some people claiming, or believing, urban legends about time travel being a reality.
Here are some of the most preposterous, and yet fascinating, persistent urban legends on the subject.
What are some urban legends about time travel?
And so, without further ado, here are some of the most notable urban legends about time travel. This list is far from exhaustive and is in no particular order.
1. The famous time-traveling urban legend of Billy Meier and the Plejarens
One famous urban legend about time travel is that of "Billy" Eduard Albert Meier and the Plejarens. Swiss-born Meier, so the legend goes, was abducted by a race of aliens called the Plejaren who decided to take him on a journey through time.
Back in the 1970s, Meier claimed that these friendly time-traveling aliens took him to prehistoric Earth (where he witnessed dinosaurs first-hand) as well as the ancient surface of Mars.
While on Mars he was, so he claimed, also introduced to Jmmaneul -- the actual Jesus. But Meier was just relying on his fantastical tale to be believed, he even, so he claimed, had photographic evidence.
However, his time-traveling snaps turned out to be a creatively decorated garbage lid with blurry images taken from contemporary books and TV shows.
2. John Titor claimed to be from the year 2036 but then disappeared
Another urban legend about time travel is the story of John Titor. He first showed up on internet discussion boards in the late 1990s with fantastical stories and predictions of the future under the pseudonym of "Timetravel_0," but later changed his screen name to John Titor.
“Food and livestock are grown locally. People spend much more time reading and talking together face to face. Religion is taken seriously and everyone can multiply and divide in their heads,” were but some of his illuminations of the near future.
He also made some interesting claims about Y2K and believed that the 2004 Olympics would be canceled due to world conflict.
However, sometime in 2001, Titor disappeared as soon as he had arrived claiming he needed to return to his own time. Most of his predictions have since been proven completely false.
3. Have you heard of the urban legend about Rudolph Fentz?
Another urban legend about time travel is the case of Rudolph Fentz. Back in the 1950s, so the story goes, a guy with mutton chop sideburns and Victorian-era duds mysteriously appeared from nowhere in the middle of Times Square.
The man looked startled, according to eye-witnesses, and was eventually run over by a car and killed. When his body was searched, 19th-century money was found as well as documents dating from 1876 that didn't appear to have aged a day.
From these documents the man's name was found, Rudolph Fentz.
Attempts were made to track down his family -- if he had any. A Mrs. Rudolph was later tracked down who just so happened to be the widow of Rudolph Fentz Jr. (the mysterious dead man's son).
Rudolph Jr., so the story goes, recalls how his father simply disappeared one day in 1876 and never returned. Shortly after it was discovered that the urban legend originated from a 1950s short story by Jack Finney.
Finney would later go on to write sci-fi classics like "Invasion of the Body Snatchers" and "Time and Again".
4. You have probably heard about "The Philadelphia Experiment"
Yet another persistent urban legend about time travel is the story of "The Philadelphia Experiment". According to the legend, back in the early-1940s, the U.S. Navy was able to render the destroyer, USS Eldridge, invisible and move it.
By all accounts, the warship was dematerialized and transported to Philadephia from Norfolk, Virginia, and back again. Some even claim the vessel was sent backward in time by 10 seconds.
Apparently, the experiment didn't go quite to plan and some of the crew remained invisible thereafter. You won't be surprised to hear that there is no real evidence for these claims, but that doesn't stop the legend persisting to this day.
It was even the subject of a 1984 film.
5. The legend of the time traveler who made a killing on the stock market
Yet another urban legend about time travel is the story of Andrew Carlssin. Apparently, in 2002, an unknown investor called Andrew Carlssin managed to turn an $800 dollar investment into $350,000,000 by trading in high-risk stocks.
Carlssin, so the story goes, was arrested and later confessed he was a time traveler from the year 2256. Sadly, like many other legends on this list, this one is also not true.
The tale first appeared in the entertainment site know for inventing fantastically fictitious stories, "The Weekly World News". Despite it being clearly fake, the story still crops up from time to time.
6. Have you ever heard of "The Chronovisor"?
Yet another urban legend about time travel is the story about a seemingly fantastical device called "The Chronovisor". The device, so the story goes, was invented by a Benedictine monk called Father Pellegrino Ernetti in the 1950s.
His invention was a form of magical television/camera that could tune into times and places in the past. Apparently, the device was used to record footage of the crucifixion of Jesus Christ, among other things.
The device, as well as the footage, is recorded, is now apparently held within the vaults of the Vatican never to be seen by the outside world. We'll let you decide on the validity of this story.
7. The interesting tale of Royal Air Force commander Robert Victor Goddard
Yet another urban legend about time travel is the story of Royal Air Force commander Sir Robert Victor Goddard. While flying over the abandoned RAF station Drem, in Scotland, in 1935, Goddard claims he experienced a time slip of some kind.
The airfield had been decommissioned after WW1, and this is exactly what Goddard saw on his first pass over it. However, on his return trip, he got waylaid in a storm and struggled to regain control.
When he did, the storm abated and Goddard was amazed to find the airfield apparently in use with aircraft and even engineers milling around. Seconds later, the storm reappeared and Goddard once again fought to keep control.
He made it home safely but later wrote about his experiences in the 1970s book "Flight Towards Reality". However, the strange thing is that the Drem airfield was indeed recommissioned in 1939 in preparation for the Second World War.
8. The famous "hipster time traveler"
Yet another persistent urban legend about time travel is the story about the "hipster time traveler". Sporting sunglasses and what appears to be a t-shirt and matching textured sweater, he was very out of place for a 1940s photograph.
It first became famous in the early-2010s, and the photo is genuine.
It captures the 1941 reopening of the South Fork Bridge in Gold Bridge, British Columbia in Canada. However, all of these items were available at the time for anyone to buy, hence it being something of a hoax.
Yet, the image is a little eerie, to say the least.
9. The urban legend of "Project Pegasus" and the U.S. "chrononauts"
And finally, another persistent urban legend about time travel is the tale of "Project Pegasus". Back in 2011, tow men, Andrew D. Basiago and William Stillings claimed that they were former “chrononauts” who had worked with an alleged DARPA program called "Project Pegasus".
The project, so they claimed, was conducted throughout the 1970s and 1980s, and the pair were chosen for a mission to Mars. Allegedly they were to travel there using some mixture of time travel and teleportation.
They also claimed to have met a young Barack Obama who was also part of the program. The claims were later officially denied by the White House.