- [Voiceover] It takes less than one second
to order stock trades between New York and Chicago.
And that's still too slow.
(upbeat dubstep music)
- You're in the early 1860s.
Riders on the Pony Express
took an insane trip through bear country,
carrying sacks of mail from St. Joseph, Missouri
all the way to Sacramento, California.
Now that's a 2000-mile trip
and they used to do it in about ten days.
It's a pretty heroic speed for the time if you ask me.
- But even the most suicidal horsemen
could not keep up with the progress of technology.
- [News Presenter] Write on a telegraph blank
and your words appear by modern magic
on paper thousands of miles away.
- Once we had the transcontinental telegraph line in place,
Pony Express became about as useful
as mobile pager would be today, and we did not stop.
We invented fiber optic cable
and this transmits data at near the speed of light.
That's a 186,000 miles per second
and it is the universal speed limit
so now it's not so much about speed, it's about throughput.
That's how much data you can shove through a length of cable
at a given amount of time.
And we've gotten really good at that too.
In 2012, communications companies got together and built a
12-core fiber optic cable capable of carrying
one petabit of information per second across 30 miles!
I know what you're saying, "What does that mean in English?"
Well, prepare to have your minds blown with a bit of math.
If a Pony Express rider carries a 20-pound bag of mail
full of letters that weigh 1/2 an ounce apiece,
that's 640 letters.
1/2 a page of printed text is usually about 1KB,
so let's say each letter contains about 4KB of written text.
That's 2.5MB of information per trip.
So let's shorten the rider's journey
to the length of a 30-mile fiber optic cable.
To equal the power of the petabit fiber,
the Pony Express would have to deliver
53,687,091 bags of mail.
Or, 34,359,738,368 individual letters every second.
But is that fast enough?
On the cosmic scale,
transmission delays can be a real kick to the cosmic pants.
Take the Curiosity rover for example.
It landed on Mars and it took 14 minutes
for a transmission from the rover to get to Earth.
14 minutes, that's half an episode of Jeopardy
before you find out if the rover landed safely or if
Jawas had sold it for scrap parts.
So is there a way to communicate faster
than the speed of light?
It's time to get a little spooky.
We're talking quantum entanglement.
That's when you entangle two quantum particles,
such as photons, and the behavior of one
tells you something about the behavior of the other.
And it's non-local,
meaning you could separate those photons
all the way across the galaxy and still by observing one
you would know the behavior of the other.
Instantaneous data transmission,
there's no travelling through space.
But there are some problems.
We aren't sure if it's even possible
to coherently send information via random quantum states and
some people bring up the fact
that nothing can go faster than the speed of light
and if you were to try it, the laws of physics would
gently tap you on the shoulder and
ask if you wouldn't mind stepping outside.
Beyond that, there's another problem.
Comes with faster-than-light communication.
You see, if I were to send a message now
using faster-than-light communication,
it would actually get to where it was going
before I had sent it.
This is a paradox that happens all the time
when we talk about these things.
You would actually send messages to the past.
Which I guess means you could send a message saying,
"Hey, don't invest in the Pony Express!"
- But, if there's one thing that Pony Express taught us,
it's never bet against science and technology.
So, even if we can't learn about
how to make this faster-than-light communication work,
I reckon we're gonna learn something pretty useful
along the way.
(peaceful music)
(whoosh)