The guy who wrote "Back to the Future" calls BS on a video claiming to have captured a real-life time traveler ... and it boils down to the logistics of breaking the space-time continuum.
Bob Gale -- who penned the scripts to the beloved '80s trilogy -- tells TMZ ... it's time to slam on the DeLorean brakes on Alec Schaal's theory that he caught a dude who actually time-traveled by popping into his shed ... and supposedly emerged way older.
In his (movie) expert opinion ... the logic simply doesn't add up to real time travel, as he's familiar with it, which is why he thinks this whole damn thing is a hoax.
As Bob points out to us ... Marty McFly (AKA Michael J. Fox) did NOT age when he traveled from 1985 to 2015 in 'BTTF II.' Actually, no one aged when they traveled through time in any of the films ... and BG thinks that same rule would likely apply to time travel in our world.
He says ... "I think someone is unclear on the concept! As I see it, the guy either has an aging machine (maybe he spent a few hours watching the news), or a makeup kit to give him those looks, or it's his father!"
In other words ... he's not buying it -- even though much of the internet has fallen for this hook, line, and sinker.
The footage -- which is actually pretty decent for such a ridiculous-sounding claim -- appears to show a random younger guy mosey onto a property before ducking into a shed. Alec says the dude had just vanished ... only to emerge a day later looking super old.
Alec thinks he has an actual time traveler on his hands... but Bob isn't saying "Great Scott" just yet -- and clearly believes we need an extra gigawatt or two to put this over the edge.