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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.