Hey!Cool?WOW is a special presentation of It’s Okay To Be Smart!
It used to be that if you wanted to get one of these from here
to here, you had to use one of these
But soon that will all be a thing of the past, when this opens.
It’s the Transcontinental Burrito HyperTunnel.
A tunnel. Dug through the Earth. Zooming burritos from coast to coast in just minutes.
Powered by nothing but gravity?
Almost sounds like something made up
for the purpose of making an elaborate and overly theatrical scientific point!
For centuries, subterranean gravity transport like this was the stuff of dreams.
But great minds of physics… made it possible.
How does it work? And what does its future hold?
We’ll explore. One of the most monumental undertakings humankind
has ever attempted, the fall and the rise of the burrito tunnel is a story for the ages.
[musical transition]
As civilization has advanced, we’ve searched for quicker
and quicker ways to transport people, information, and everything else, from there to here.
And not just faster ways of traveling,
but also faster routes between where we are and where we want to go.
Columbus was just looking for a shortcut, too. But what he found was the Americas,
a land full of rich and vibrant cultures. Like the Aztecs, a people who had invented quite a
few things of their own. Including an ingenious way of making a meal easy to carry: the tortilla.
Fast forward four centuries or so, and that wrapped up meal has evolved into this.
The burrito. A self-contained meal in a flawless geometric shape. And the most perfect
of these perfect foods are made in the “Bordeaux of Burritos”: San Francisco’s Mission District.
Problem is, if you’re in, say, New York… how do you get one of these in just minutes?
Forgetaboudit
Science changed all of that…
Not too long ago, you could get a hot fresh burrito from
3,000 miles away delivered to you in around 40 minutes. You may have heard of it...
In 1956, Duane Roberts had found success selling frozen burger patties to McDonalds.
So he turned his attention south of the border for his next invention:
The frozen burrito. You may have heard of it. He realized there was money to be made
if burrito makers on the west coast could flash freeze their creations
and get them to hungry mouths on the east coast by using refrigerated trucks, trains, or planes…
Or, say, using a burrito-sized tunnel through the Earth.
Wouldn’t that be something?
Roberts’ idea was to use gravity to propel burritos through a deep transcontinental tunnel,
in a nearly perfect vacuum, wrapped in special foil to enable frictionless magnetic levitation,
allowing coast-to-coast burrito travel at speeds once imagined only for space vehicles.
Sounds too good to be true. And it was, until Mr. Roberts eventually built it,
at a cost of $420 thousand billion dollars.
And to figure out how it worked, we have to go back to 17th century England.
A guy named Robert Hooke wrote a letter to a guy named Isaac Newton.
Maybe you’ve heard of him?
They were trying to figure out what would happen if you dropped a ball
down a hole that reached through the Earth.
But they might as well have dropped some rice, beans,
meat, cheese, and avocado wrapped in a tortilla. Because what Newton realized
about gravity inside the Earth is the reason Duane Roberts’ burrito tunnel ever worked.
There’s a gravitational force acting on you, right now,
from the Earth. And the same force is acting on all the things around you.
We call it gravitational potential, because it means something has the potential to move.
How much potential? That depends on how far you are from the center of the planet.
So if you dig a tunnel down through the center of the Earth, like Newton and Hooke imagined,
all the way to the other side, and drop a burrito in, what happens?
Whew,
that would be one hot trip!
For a moment, let’s imagine that Earth is a perfect sphere, and the same density the
whole way through. In reality neither of those things are true, but let’s pretend.
The pull of gravity from the whole Earth sphere is the same as if all its mass was concentrated
at a point right in the center. Because the stronger pull from whatever side is closest to you
and the weaker pull from the side farthest away, they just cancel each other out.
But what about INSIDE the Earth? As the burrito falls,
and the distance between it and that center mass shrinks,
it feels the same gravitational potential as it would on a smaller, lighter Earth.
As if we were just peeling layers off of Earth:
As the burrito falls, and the closer it gets to the center of all that gravity, it’ll keep
speeding up, but it’s being pulled less and less, because there’s less of Earth’s mass under it.
Once it’s past the center and hurtling toward the other side?
Now it’s being slowed down by the gravity of a rapidly enlarging Earth.
Now what about this path? It works an awful lot like a pendulum. Only instead of gravity staying
the same and the path changing, it’s gravity that changes, and the path stays straight.
The burrito goes downhill and uphill on a straight line.
WHOOOA that’s weird
Newton and Hooke also realized something pretty weird. It turns out it takes the same
amount of time to make the trip no matter what two points on Earth you connect.
How long?
Exactly 42 minutes, for an Earth with uniform density.
The closer your tunnel is to Earth’s center you get going faster,
but you’ve got a longer distance to travel.
But because the Earth’s density isn’t the same all the way through,
the time could range anywhere from 42 to 38 minutes, depending on how deep your tunnel is,
the density of the Earth at different depths, and complicated physics things like that.
For a few glorious years, at a maximum depth of 315 km below the Earth,
Duane Roberts’ Original Transcontinental Burrito Tunnel delivered hot fresh Mission burritos,
coast to coast, in the same time it takes to get a pizza.
But after the excitement of the Apollo moon landing had worn off,
and thanks to an influx of convenience dining options ranging from gas station
sushi to whatever Arby’s is, the transcontinental burrito market crashed.
42 minutes was too slow for the modern food consumer.
The original tunnel is closed, and the remains of its burrito processing plant are that’s left.
Duane Roberts was better at making cold hard burritos than cold hard cash.
There was one obstacle he could never overcome: In a tunnel through the Earth, there’s a speed limit.
That is, unless, you dig a different sort of tunnel.
A few years ago, a young inventor named Egon Shmusk had an idea.
He loved California burritos too, and he knew
he could ship them coast to coast faster than Roberts’ straight line tunnel ever could.
Remember how this all got started in the 17th century with Newton and Hooke
thinking about holes through the Earth? A couple decades after them,
a fella named publicly challenged the world’s mathematicians to solve this problem:
Powered only by gravity,
what’s the path that connects two points in the shortest amount of time?
Bernoulli thought he was hot stuff. It’d taken him about two weeks to come up with the answer,
so he was pretty surprised when he got an anonymous letter from someone who
claimed to have solved it in one night.
Turns out that letter came from… you guessed it: Isaac Newton, who was very smart.
Newton and Bernoulli figured out the shortest path, a straight line, isn’t the shortest time.
Inside our circle, let’s trace a path using the edge of another circle.
There. That’s called a hypocycloid.
Travel down that path, and you’ll beat any other path between those two points,
every time–whether you’re talking burritos, or a subterranean passenger train.
They called it The Brachistochrone curve. It’s Greek for “shortest time”.
It’s the perfect balance between picking up speed early, and keeping the total path length short.
And when Egon Shmusk learned about that,
he took the fortune he made selling electric scooters and started digging.
And his spicy innovation? A brachistochrone hypertunnel!
In two years time, the Transcontinental Burrito HyperTunnel is scheduled to begin operation.
When it opens, customers in New York City will be able to get burritos from San Francisco in just
over 25 minutes, hot and fresh, warmed in their wrappers by the geothermal convection currents
of our planet’s mantle, 17 minutes faster than Duane Roberts burrito tunnel ever could,
and fast enough for a lunch break in today’s fast-paced virtual reality
internet web connected algorithm computer semiconductor quantum social media society.
But it’s not without its challenges.
The brachistochrone tunnel’s greater depth than its predecessor, running nearly 1300
km below Nebraska at its lowest point, means enormous pressures and extreme temperatures
nearing 2000˚ Celsius. It required Shmusk’s engineers to build their tunnel walls,
their magnetic rails, and even their robotic mining drill out of a newly-discovered,
nearly indestructible metal alloy called Unobtanium.
Invest in Unobtanium! You’ll be a hundredaire
So what’s next? Are brachistochrone burritos just another pipe dream?
Or are taco tunnels on Titan next? Maybe sushi on Europa? That’s the funny thing about technology.
Often the right path isn’t the easiest one. But with enough creativity and innovation,
there’s always light at the end of the tunnel. And also burritos.
And besides… hot, fresh deliciousness like
this, there’s just no other way to do it… except tomorrow’s science.
Stay curious.