What is time?
A deceptively simple question, yet it is the key
to understanding relativity.
It is sort of the reason my hair is going gray.
[laughter]
When we describe motion, we do so
as a function of time, 10 meters per second, 100 miles per hour.
But the mathematical description of velocity
is moot unless we can define time.
Is time universal?
In other words, is there an audible tick-tock
throughout the galaxy, a master clock, so to speak,
forging ahead like Mozart’s metronome?
The answer my friends is no.
Time is not absolute.
In fact, for us, the living physicists, the distinction
between the past, present, and future
is but a stubborn illusion.
[music playing]
A lot to consider, I know.
I know.
[laughter]
But understanding time is essential to understanding
relativity.
Now, I want you all to close your eyes.
Not to worry, I don’t bite.
But I am on the lookout for a new pen.
[laughter]
Go on close your eyes.
To truly grasp the idea of time, we must take a step
back and ask, what is light?
So journey with me to the Sun.
Light travels from the Sun to the Earth through space, yes.
When I was your age, I wanted to know
how can something, light, travel through nothing, space?
Let us isolate a light beam and travel alongside it.
But let us go faster.
You’re there with me.
Faster.
Faster!
What is time?
[thud]
PROFESSOR WEBER: Herr, Einstein, wake up!
I wasn’t sleeping, sir.
I was thinking.
Oh, really.
About what exactly?
The secrets of the cosmos, I suppose.
I suggest you think about trigonometry
instead, with your eyes open.
And sit up!
Laws of sines and cosines?
c squared equals a squared plus b squared, subtract
2 [inaudible] cosine b.
PROFESSOR WEBER: The area of a triangle?
STUDENTS: The area equals b squared times a times
b over 2 times c.
PROFESSOR WEBER: What is the solution [inaudible]
differential equation?
Herr Einstein, are you still too busy contemplating
the secrets of the cosmos to solve this equation?
Oh, no sir.
I’ve already solved it.
PROFESSOR WEBER: Leave, now.
On what offense?
PROFESSOR WEBER: Your mere presence spoils the respect
of the class for me!
That is not an objective reason.
Out!
[music playing]
The natural log of a constant multiplied by x
equals the natural log of 1 plus v squared.
And since v equals y over x, that gives us
the final function, x squared plus y squared
minus c x cubed equals 0.
And speaking truthfully, sir, your mere presence
spoils my respect for the future of Prussian mathematics.
Out.
[door slamming]
