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MARKUS KLUTE: Welcome
back to 8.20--

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Special Relativity.

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In this short video, we look
at the historic backdrop,

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the time in which Einstein
was able to develop the theory

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of special relativity.

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What were people thinking?

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What was the physics
landscape of the time?

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How was technology developed?

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And how did all those things
come together for Einstein

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to thrive and come forward with
those important discoveries

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in physics?

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We have to go back to 1900,
around that time in which

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Einstein was able to break
through, break out, and come up

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with completely new
ideas in physics.

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Before we go into the
discussion of the timelines,

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I'd like you to be invited to
come to Geneva, to Switzerland,

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to Bern, to Zurich-- to
the places in which this

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all happened.

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Especially Bern is
a historic town,

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wasn't destroyed in
the Second World War.

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And if you walk
down the streets,

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here is a picture
of me two years ago

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in front of the Einstein house.

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The streets are basically
unchanged for the last 150

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years, so you look
up into the window,

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and you see Einstein
looking down at you.

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So if you go back
200 years, in Italy,

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people like Volta
and others started

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to make use of
electromagnetic effects.

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The first batteries
were developed.

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And a theory, a wave theory
of light was developed.

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That then let-- slowly
developed into the theory

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of electromagnetism
and the understanding

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of those phenomena.

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And the very same
time, in Europe,

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the first railroad
systems were developed.

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Electromagnetic
induction was understood.

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And then in the
1860s, Maxwell was

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able to put all
of those concepts

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together in his famous Maxwell
equations, which are discussed

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at length in 8.02.

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People were then,
because of the railroads

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but also because of
telegraphic cables,

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able to communicate and
move over a larger distance

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in a shorter amount of time.

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And that led to the need
of synchronizing clocks.

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To that point, in each town
had one or a few clock towers.

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And you just read off the time,
and it was the time of day.

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There was no need
to be able to tell

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what time is it in
London when you have

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your breakfast in Munich or
what time the store opens

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in a different city.

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There was no need for this
kind of synchronization.

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But with the expansion
of railroads,

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specifically, there was
a need to understand

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when a train when a train
is on a track and such

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that it doesn't intersect
with another train, avoiding

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collisions.

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You also want to know when you
have to be at a train station

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in order to catch the train.

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Those things became
important, and they

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led to patents filed around
this time and also later on.

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On the theory of light,
people developed all kinds

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of ideas and conflicting
ideas of, for example,

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mechanical models
of light, which

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relied on the existence of a
medium in which light travels.

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And we'll discuss
this at length.

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In the 1880s, there's
a new phenomena

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in the structure of physics.

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Up to this point,
there was a professor

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of physics at an institute.

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He had a chair, and everybody
was working for them.

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But then there was
a change in the way

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physics research was conducted,
such that there started

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to be a division of labor
between experimental physicists

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and theoretical physicists.

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Around this time, Thomas
Edison developed light bulbs,

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meaning that light
and electricity,

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those two things became
more woven together.

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Electromagnetic waves
were discovered.

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And Michelson and Morley
conducted the experiment.

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And they did not find a medium
which carried light waves.

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And we'll discuss the
Michelson-Morley experiment

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in much more depth.

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But this was basically
the backdrop.

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Michelson and Morley-- the
idea of electromagnetic waves,

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how do they actually travel.

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What is the speed in
which they travel?

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What are the medium?

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And how does this all interact?

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So Einstein was born into this.

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He was born in Ulm, a German
town, a small German town,

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on March 14, 1879, on Pi Day.

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He spent his youth in
Munich, where his father--

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he had an electrical
company, a company

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which provided electrical
services-- for example,

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for the Oktoberfest in Munich.

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And his business
went up and down

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and had to be relocated
later into Italy.

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It was a difficult
and interesting time.

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So Einstein went to
school in Munich,

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in a gymnasium in Munich.

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And at some point,
it was time for him

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to go to military service.

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And he avoided this
by becoming stateless.

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He then wanted to enroll in
a university in Switzerland,

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Polytechnic of the
Eidgenossische Technische

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Hochschule in Zurich.

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But he wasn't quite admitted,
mainly because his French

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wasn't quite sufficient.

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So he had to go an extra round
of studying in order to be then

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admitted to the Polytechnic.

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One of his mentors at the
time was Herr Professor Weber.

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He was a leading
physicist there.

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And they had an
interesting relationship,

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which I come back to
in a little while.

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While studying in
Zurich, Einstein

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met his wife, Mileva Maric.

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She was also a physics student,
one of the few female physics

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students there.

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And they fell in love,
and they married.

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And they had a child together,
or children together.

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In 1900, Einstein graduated.

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He wasn't the best
student in class.

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Neither was Mileva Maric.

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And he had a hard
time finding a career.

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So he wanted to stay
at the university

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and enter an academic career,
and that required the mentors

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to be in favor of this.

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And since Einstein didn't quite
develop a good relationship

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with Herr Weber and the
other professors around,

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they didn't want him there.

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They didn't promote his career.

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So he didn't know
quite what to do--

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went back to his
parents, to Italy,

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and didn't get any
traction from where he was.

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And he was quite anxious
about this, which

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is visible in letters he wrote.

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But he had good friends there.

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He had a good friend, Marcel
Grossmann, specifically,

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who helped him get into,
after some back and forth,

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a position as a lower
level patent clerk

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in a patent office in Bern.

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And so this was the
starting point for a career.

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So he had this-- he
was a patent clerk.

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He had a lot of time on
his hands beyond that.

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And that started something
which was called the Olympia

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Academy, which consisted
of a group of people who

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studied with and
friends of Einstein,

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including Marcel Grossmann.

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And they talked and spent
time, took long walks,

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spend time drinking,
partying, if you want,

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but specifically
talking about physics.

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And in this framework, Einstein
was able to develop this ideas.

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And then 1905 came--

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not in a sudden, but in 1905, he
was able, out of this context,

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to develop five very,
very important papers.

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The first one was
on light quantum.

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He was able to
describe the emission

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and absorption of light.

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In April, then, which was
part of his PhD thesis,

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he was able to characterize
the size of molecules.

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And in May, he was able to
show the existence of atoms.

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He was basically
demonstrating this

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by following Brownian
random motion of atoms.

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And then in June, he wrote a
paper named electrodynamics

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of moving bodies.

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And that is the paper in which
he discovers or describes

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special relativity.

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On further review, he
discovered that there's

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a consequence of
special relativity

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that energy and mass are
equivalent in his famous

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equation E equals mc squared.

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And we'll come to this, as well.

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So this is basically the
framework of this lecture.

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If you then move forward into
general relativity, which

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was developed by
Einstein in 1915,

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you can then, again,
follow the development

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of signs of quantum mechanics
of general relativity

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and the conundrum of
describing those two

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concepts at the very same
time, in which, then, Einstein

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lived and moved.

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His career developed
then from there on,

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not instantly but
systematically.

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He had a call as a
professor in Berlin later on

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and, after the Nazis
took over in Germany,

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decided to flee Germany.

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And he moved to
the United States,

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where he took on a
position in Princeton.

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The rest is history,
as you want,

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and we'll hear more
about this tomorrow.