The story of physics is, for the most part,
a tale of ever-increasing confidence.

For 300 years, physics was all about observing
and measuring —finding out how stuff works.

In the early 1600s, an Italian got the ball
rolling, by measuring and observing

balls rolling.

Galileo, also timed pendulus, and dropped
different-sized objects

off the leaning tower of Pisa
to see what would happen.

And, despite upsetting the Pope —his ideas
had apparently made God very crossed—,

Galileo's work became the rock on which
modern physics is founded.

Later, free from angry Popes, Isaac Newton
moved things on by abandoning balls

and embracing apples.

Why, he wondered, did they always fall
downwards? Not sideways, or up.

By 1687, he had an answer; it was a force
called gravity, which worked on balls

and apples. And planets, holding them in
nice predictable orbits around the sun.

In the 1800s, James Clerk Maxwell cast his
eye over more mysteries.

He showed how electricity and magnetism
are related, and can be combined as

one force: electromagnetism. And that light
had electric and magnetic parts,

and traveled in waves, like water.

Physics was now on a roll.
New discoveries built on earlier ones,

and some even had practical uses: Newton's
laws predicted the existence of Neptune;

Maxwell's work gave us radio and tv, and
there's nothing much more useful than that.

Physicists seemed to have mastered the
universe;

all that was left was to plug a few 
remaining holes.

But, by 1900, the holes were getting bigger.
The latests discoveries didn't build on

the old ones. Things like X-Rays and radioactivity
were just plain weird, and in a bad way.

All was not well in the world of physics.
Top scientist Lord Kelvin saw dark clouds

hanging over the subject.

Then, in 1905, a Swiss patent clerk started
a full-on storm.

26-year-old Albert Einstein tore up the
script. First, he claimed that light is

a kind of wave, but also comes in packets,
or particles. In the same year, he published

his famous equation: E = mc^2. It says that
mass and energy are equivalent.

And if that wasn't shocking enough, he
released the mind-blowing results of a

thought experiment. So, hold on to
your heads.

It starts with the assumption that the speed
of light in a vacuum is constant.

Now, imagine that someone watches a spaceship
flying very fast. What they would see

is the ship's clocks running slower than their
own watch; and the ship will actually

shrink in size.

But, for the astronauts inside, all would be
normal.

Einstein said that time and space can
change. They are relative depending

on who's observing them.
This is special relativity.

Now, special it might have been, but it
wasn't enough.

Albert had only just started. Next he showed
how balls and apples weren't

the only things subject to gravity.
Light, time, and space were also affected.

Gravity slows down time, and it warps space.
The stronger it is, the more space is warped

and the more light is bent. Einstein called
this "general relativity."

His ideas shattered traditional physics.
He'd opened the door onto the weird world

of the quantum, where cats can both be alive
and dead, where good plays dice,

and where everything is uncertain.

His famous equation lead to nuclear energy.

Without special relativity the Large Hadron
Collider would be pointless.

General relativity predicted both black holes
and the Big Bang, an idea now endorsed

by both Church and science.

Galileo would have been pleased.
Well done, Albert.