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

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

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

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balls rolling.

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

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

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

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

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

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and embracing apples.

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

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

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

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

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

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

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and traveled in waves, like water.

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

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

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

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Physicists seemed to have mastered the
universe;

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

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

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

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

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hanging over the subject.

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

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

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

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

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

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thought experiment. So, hold on to
your heads.

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

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

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

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shrink in size.

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

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

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

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

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

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

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

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

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

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

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and where everything is uncertain.

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His famous equation lead to nuclear energy.

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Without special relativity the Large Hadron
Collider would be pointless.

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

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by both Church and science.

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Galileo would have been pleased.
Well done, Albert.