Quantum Entanglement Simplified

When people talk about the universe,
they usually mean the vast expanse of space.

Billions of lightyears across,
that they can see with radio telescopes…

…and cosmic imaging.

They think about stars
and galaxies and planets…

…and all the big stuff out there.

You have astronomical bodies moving
under the force of gravity.

However, there is another universe.

An unseen world,
that governs everything we see.

When we go down in size
trillions of times smaller…

…to the microscopic world…

…the rules are much less intuitive then
the ones we are used to from the large scale world.

The magic of the microscopic universe
begins at about a ten billionth of a meter.

Or the size of an atom.

Matter behaves so differently
at this level…

that scientists have developed
an entirely new set of rules…

to describe what’s going on.

They call it Quantum Theory
and what it says is extraordinairy.

This baseball represents a subatomic particle
like a an electron or a foton of light…

…that routinely does
all sort of weird, strange things…

in the microscopic universe.

The sub-atomic version of this baseball:
can be invisible,

can go through solid objects with ease,

can be in multiple places at the same time,

and can, seemingly, go backwards in time
and change the past.

This means I can throw
this microscopic baseball…

…to first base and to home plate
at the same time…

…or change the seemingly
predetermined outcome…

…of a play
while it’s still going on.

Now, this is the stuff of science-fiction
but really we know it to be true…

…or, at least, it appears to be true
in our quantum world.

We get all sorts of weird things happening.

If scientists can understand
how these weird things work…

…they’ll be able to put them to use
in our everyday world….

revolutionizing modern computing…

and perhaps even allowing us to communicate
across the cosmos, instantly.

The key to making this miracles come true
is a process called Quantum Entanglement.

In Quantum Physics,
what happens to an object over here…

…can instantly affect
an object over here…

…and ‘over here’
could be millions of miles away.

This is how it works:

when two sub-atomic particles interact,
they can become entangled.

That means their spin, position
or other properties become linked…

…through a process unknow
to modern science.

If you then make a measurement
of one of the particles…

…then that instantaneously determines
what the behaviour of the other particle should be.

And when the experiment is done
it is found that, indeed,

the other particle’s quantum state
is exactly determined…

once you’ve made a measurement
of the partner particle’s quantum state.

That means if a scientist
observes one entangled particle…

…and forces it to spin clockwise.

…the other entangled particle
will immediatly start spinning in the opposite direction.

That seems intriguing
but it’s hardly earth shattering…

until you consider
that the two entangled particles…

…can be seperated
by billions of lightyears..

…and still, the moment you observe
one particle’s spin…

…you’ve dictated the other particle’s spin.

That’s weird, because it may suggest
that information has travelled instantaneously…

faster than the speed of light
from one particle to another.

I don’t understand it,
I don’t know that anyone does.

Spooky action at a distance
as Einstein called it.