00:00Time travel, you know? It's the stuff of sci-fi movies and epic novels, right?
00:05Well, today, we're going to peel back all that fiction and take a hard look at the actual science behind
00:09it all.
00:10And we're going to kick things off with a story that, honestly, feels like it's straight out of Hollywood.
00:15Take a look at this number.
00:18$350 million.
00:20I mean, that is just a staggering amount of money.
00:22But here's the truly mind-blowing part.
00:25That massive fortune?
00:26It was made in just two weeks, and it all started with an investment of only $800.
00:32A return like that isn't just lucky.
00:34It's, well, it's basically impossible.
00:37And yeah, back in March of 2003, the FBI thought so, too.
00:41It just screamed insider trading.
00:43So they arrested a man named Andrew Carlson.
00:46But his explanation for how he did it?
00:48Well, it was something else entirely.
00:50He told them, flat out, that he was a time traveler from the year 2256.
00:55He said he knew exactly which stocks were going to pop because, for him, it was all just history.
01:00Now, here's where it gets really weird.
01:01When investigators tried to find him, you know, birth certificate, social security number,
01:05they couldn't find a single record of an Andrew Carlson existing anywhere before December 2002.
01:10And then, just like that, poof, he was gone.
01:14Some anonymous person posted his million-dollar bail, and right before his court hearing, he vanished.
01:19Never seen again.
01:20So you have to ask, could he have been telling the truth?
01:23Is time travel actually real?
01:25Well, to even begin to answer that, we have to understand what time is.
01:29For centuries, we were all on Team Newton.
01:32His view was that time is like an arrow, flying straight, at the exact same speed for every single person
01:38in the universe.
01:39But then, then Albert Einstein came along and just flipped the whole game on its head.
01:43He said, no, time is more like a river.
01:46Its flow can change.
01:48It can speed up.
01:48It can slow down.
01:49And that one idea right there is the key to everything.
01:53This all hinges on a concept called time dilation.
01:56It's Einstein's big idea that your experience of time isn't fixed.
02:00It's relative.
02:01And it can actually be stretched or compressed by two of the most fundamental forces we know of, speed and
02:07gravity.
02:07And what that gives us are two scientifically plausible ways to get a one-way ticket to the future.
02:13You either need to go unbelievably fast, or you need to cozy up to something unbelievably heavy.
02:20Let's break that down.
02:21So, first up is speed.
02:23The fancy term is kinematic time dilation.
02:26But the rule is actually pretty simple, even if it messes with your head.
02:30The faster you fly through space, the slower you move through time.
02:33At least compared to someone who's just standing still.
02:35And look, this isn't just some theory on a chalkboard.
02:38It's been proven.
02:39Back in 1971, scientists and the Haefeli Keating experiment put these super-accurate atomic clocks on jetliners and just flew
02:47them around the world.
02:48And guess what?
02:48When they landed, the clocks on the planes were just a few nanoseconds behind the identical clocks they left on
02:53the ground.
02:54The pilots literally aged a tiny, tiny bit slower.
02:57They had traveled microseconds into the future.
02:59Okay, the second method is all about gravity.
03:02Einstein imagines space and time as this single, connected fabric.
03:06And a massive object, like a planet or a star, is like dropping a bowling ball into that fabric.
03:10It creates a deep curve, a dip.
03:13The heavier the object, the deeper the dip, and the slower time itself actually flows for anything near it.
03:19In fact, you use this principle every single day.
03:21The GPS satellites orbiting way up above us are further away from Earth's gravity, so their clocks actually tick just
03:28a little bit faster than ours do down here.
03:30For your GPS to work at all, engineers have to constantly correct for that time difference.
03:35It's pretty wild.
03:36Time travel is literally built into your phone's map app.
03:38So, who holds the world record for time travel?
03:42It's a Russian cosmonaut named Gennady Padalka.
03:45By spending a total of 879 days in orbit, zipping around our planet at over 17,000 miles per hour,
03:52he traveled 0.02 seconds into his own future.
03:55He is, literally, younger than he would have been if he had just stayed home.
04:00Okay, so, we've pretty much established that traveling to the future isn't science fiction anymore.
04:05We're already doing it, even if it's just by tiny fractions of a second.
04:09But that brings us to the big one, the one everyone really wants to know about.
04:13What about going back to the past?
04:15This is where we step out of proven science and into the really wild world of theory.
04:20Some physicists, like the brilliant Kip Thorne, have suggested that maybe, just maybe, a spinning black hole could twist space
04:27-time so violently that it could actually loop back on itself, creating what we'd call a wormhole.
04:32In physics, they call it a closed time-like curve, which is a fancy way of saying a pathway to
04:37the past.
04:38But, and you knew there was going to be a but, right?
04:40It is a massive one.
04:42To actually keep that cosmic tunnel open long enough for someone to get through, we would need something called negative
04:48energy.
04:48It's a hypothetical substance that would have to have anti-gravity properties, and we have never, ever seen it, and
04:54we have absolutely no idea how to make it.
04:56But let's pretend for a second we could solve that.
04:59Even if we could build the machine, we immediately slam into a wall that's even bigger than the physics.
05:04I'm talking about the complete breakdown of logic itself.
05:07I'm talking about paradoxes.
05:09You've probably heard of the most famous one, the grandfather paradox.
05:13It goes like this.
05:14You build a time machine, you go back in time, and you stop your grandparents from ever meeting each other.
05:20Well, if you do that, then you're never born.
05:22But if you were never born, then who went back in time to stop them in the first place?
05:27You see?
05:27It's a perfect, circular, inescapable contradiction.
05:31And then there's another mind-bender, the predestination paradox.
05:35This idea says you can't change the past because, well, you were already a part of it.
05:39Let's say you go back in time to save a friend from a terrible accident.
05:42This paradox suggests that your very attempt to intervene, your presence there, might be the very thing that causes the
05:49accident.
05:49History is a closed loop, and you're already in it.
05:52Which, of course, brings us all the way back around to our mystery investor, Andrew Carlson.
05:57Given everything we know now, from time dilation to paradoxes, could his story possibly be true?
06:03Well, the truth is, not exactly.
06:06The whole incredible story came from just one place.
06:10An article in a paper called The Weekly World News.
06:14And if you're not familiar with it, The Weekly World News was a famous satirical tabloid.
06:19Think Bat Boy, Elvis Sightings, that kind of thing.
06:22It was pure entertainment, totally made up.
06:24The story was just so good that a few other news outlets actually picked it up and reported it as
06:29fact.
06:30But yeah, it was a hoax from the very beginning.
06:32So even though the story of Andrew Carlson isn't real, it does make you think, doesn't it?
06:38Traveling to the future is a scientific reality.
06:40But going to the past seems totally locked down by paradoxes and physics we can't even imagine.
06:46And that leaves us with one last lingering question.
06:49One that the great Stephen Hawking famously asked.
06:51If travel to the past is ever possible, where are all the tourists from the future?
06:56The future?
06:56Here we go.
Comments