This video was made possible by CuriosityStream. When you sign up at curiositystream.com/HAI,
you’ll also get access to Nebula—the streaming service that HAI is a part of. Ahh, the roaring twenties. Flapper girls, the Harlem Renaissance, prohibition,
Art Deco, the birth of Hollywood, automobiles, women talking on cellphones, the Teapot Dome
scandal… wait, sorry, back up… was that a woman talking on a cellphone? Yeah, look at that. This background actor in Charlie Chaplin’s
1928 film ‘The Circus’ is definitely holding some kind of modern-looking cellphone. Now, you know me. I like to come to quick, simple conclusions
without any evidence or further explanation, so it’s very tempting for me to jump on
the internet bandwagon, declare this woman a time traveler, and get back to my busy schedule
of not acknowledging your demands for me to make a brick video. Unfortunately, my advertisers said they’d
drop me if I started spreading misinformation, so I’m legally obligated to point out that
there weren’t cell towers in 1928, this cellphone would have no way of operating without
cell towers, many archivists have determined that the object she’s holding is not a cellphone
and actually an early hearing aid called an Acousticon, and that time travel isn’t possible. Except, it kind of is. In fact, there’s a world record for time
travel, and it’s held by this guy: Sergei Krikalev, who has traveled a full 0.2 seconds
into the future. Okay, well, I guess that doesn’t sound as
exciting as this woman who appears to have traveled back to 1928, but he actually did
it, okay? The only world record she holds is “most
controversial hearing aid,” and maybe “dumbest hat.” As for Krikalev, his time-traveling exploits
are very real, but they’re gonna require a super quick explanation of gravitational
time dilation and Einstein’s theory of special relativity. Alright, so, basically, time and space are
interconnected in a giant four-dimensional sheet called spacetime. When mass is placed on that sheet, it becomes
warped, which affects both the gravity and relative rate of time in that part of the
sheet. It’s sort of like how when you are placed
on your sheet, you start to experience time differently, or maybe that’s just you taking
a nap and waking up later. I’m not sure. But analogies aside, it’s also important
to note that energy can warp spacetime, so objects moving at different velocities can
also experience time at different rates relative to one another. It’s sort of like how when you stop moving
and get into bed, time seems to accelerate, or maybe that’s just you taking a nap again. Look, you just need to know that time moves
at different rates depending on forces like gravity and velocity and mass and all that
other good stuff, okay? Good. Now that we’re all physics experts, let’s
meet Sergei. Sergei is a Russian cosmonaut, and former
Soviet cosmonaut, before the Soviet Union dissolved and left him stranded in space for
311 straight days. But, in total, Sergei has been in space for
exactly 803 days, 9 hours, and 39 minutes, or roughly the time it takes to get through
the security line at Newark airport. Now, in space, two forces are acting on the
flow of time around you: low gravity and super high velocity. The low gravity, actually, makes time move
faster in space, which would have Sergei going back in time upon returning to Earth, but
this is cancelled out by the space station traveling at just under 5 miles per second
making time move much slower instead. Traveling that fast, for that many days, means
that Sergei technically traveled into his own future, and is going to live 0.2 seconds
longer relative to everyone else on earth. And also probably a lot longer than that,
cause the dude is just in plain good shape. I mean, look at him. Look at that jawline. Phew! Anyway, you’re probably wondering now, “Well,
I haven’t been in a space station, but I have traveled pretty fast on a plane, or in
a car, or I’ve run really, really quickly over to my computer because I got a notification
that a new HAI video was out—does that mean I’ve time traveled, too?” And the answer is… yes, technically. In fact, you can use this equation to determine
just how much time you’ve gained over your sad, boring friend who has been sitting perfectly
still at sea level for his entire life. But before you book tickets to live out the
rest of your life on a commercial airliner, I should point out that the gravitational
time dilation in airplanes usually balances—or even overtakes—the effects of the velocity. That is to say, if you lived the rest of your
life on an airplane, it might end up being ever so slightly shortened by the effects
of lower gravity on time, and also the effects of only consuming peanuts and tiny bottles
of gin on your body. If you really wanted to extend your life,
you’re much better off living on something like a bullet train, or, y’know, just wearing
a damn mask. Now, you might remember a video we made about
a year ago about why the Hudson Bay region of Canada has less gravity, but what we didn’t
tell you is that time also moves ever so slightly faster there, too. In fact, because of gravitational time dilation,
time moves at different rates on different parts of the earth, and it even moves slightly
faster at the top of your head than the base of your feet, unless, I guess, you’re doing
a handstand, in which case you’re probably having too much fun to be worried about stuff
like this anyway. But if you’re looking for the place on earth
where time goes by the very slowest, look no further than here, Newark International
Airp—wait, sorry, we’ve hit our Newark roast quota for the month. The actual answer is probably deep in a cave
somewhere in Chile, but because of the Earth’s shifting crust, its gravitational field changes
over time, too, so we never quite know just how fast time is moving around us. Now, if you manage to bend space and time
to score an extra 0.2 seconds on Earth, I would recommend using that extra time to watch
the first 0.2 seconds of HAI’s first 30-minute special, featuring a super special mystery
guest, and premiering exclusively on Nebula very, very soon. Now you could just get a subscription to Nebula
for 30 dollars a year, but I’ll let you in on a little secret: by signing up for CuriosityStream
at curiositystream.com/HAI, you’ll get a subscription to Nebula for free, and you’ll
also get an incredible library of thousands of documentaries by big names like Nick Offerman,
Jane Goodall, and Stephen Hawking. Also, for a limited time, CuriosityStream’s
annual subscription is on sale for just $15 a year. That’s half the price for double the streaming
services, so now is definitely the time to sign up. Once again, that’s two amazing streaming
services, countless hours of content, and a super special 30-minute HAI original that
you won’t wanna miss, all by signing up at curiositystream.com/HAI.
