March 14 – It’s All Relative

Today’s Factismal: Casablanca’s song “As Time Goes By” is about relativity.

If you’ve ever seen Casablanca (and if you haven’t why not? Go rent it now!), then you know the song that Sam sings to Elsa. In a plaintive key, Sam tells of the things that should stay constant in one’s life. But what you may not know is that Sam is only singing the middle part of the song; there’s actually a lot more to it:

This day and age we’re living in
Gives cause for apprehension
With speed and new invention
And things like fourth dimension.

Yet we get a trifle weary
With Mr. Einstein’s theory.
So we must get down to earth at times
Relax, relieve the tension

And no matter what the progress
Or what may yet be proved
The simple facts of life are such
They cannot be removed.

You must remember this
A kiss is just a kiss, a sigh is just a sigh.
The fundamental things apply
As time goes by.

And when two lovers woo
They still say, “I love you.”
On that you can rely
No matter what the future brings
As time goes by.

Moonlight and love songs
Never out of date.
Hearts full of passion
Jealousy and hate.
Woman needs man
And man must have his mate
That no one can deny.

It’s still the same old story
A fight for love and glory
A case of do or die.
The world will always welcome lovers
As time goes by.

Oh yes, the world will always welcome lovers
As time goes by.

Words and music by Herman Hupfeld
© 1931 Warner Bros. Music Corporation, ASCAP

That’s right – the song actually starts out with the effects that Einstein’s theory of relativity had on the world. Even today, relativity is one of the most misunderstood scientific discoveries, what with its twin paradoxes, its strict speed limit, and its statement that elevators and planets are the same. Because it so offends “common sense”, relativity is also one of the most-tested ideas in science and thus far it has passed every test.

Most recently, some scientists at the Large Hadron Collider thought that they might have detected some subatomic particles traveling faster than the speed of light, in violation of relativity. But then other scientists started looking at the data and discovered that one of the cables for the experiment at CERN was loose, which added a slight delay to the signal making it appear that the particles were traveling faster than the speed of light when they were actually obeying the speed limit. Once more, relativity was the victor.

Albert Einstein (Image courtesy Nobel Prize Foundation)

Albert Einstein (Image courtesy Nobel Prize Foundation)

But who came up with the crazy idea of relativity in the first place? It was a young German scientist by the name of Albert Einstein, who was born on March 14, 1879. (He’d be 134 years old today – assuming that he had stayed on Earth.) He had studied physics in Switzerland and hoped to be a teacher but was unable to find a position. So he worked as a patent clerk and spent his spare time working on what he thought of as interesting problems in physics. His spare time was put to good use; in 1905, he published four papers that were to change physics as we know it.

At the time, his best-received paper was an analysis of Brownian motion. For centuries, scientists had been amazed by the random motion of small particles of dust; what caused those motions? Einstein was able to show that the random motion of gas molecules could cause dust mores to move erratically. In doing so, he provided empirical support for the existence of atoms.

Another important paper was his description of the photoelectric effect. It was well-known that exposing a metal to sunlight would cause it to give off electrons (this is the basis for today’s solar cells). What wasn’t known is why it happened only for certain colors of light and why increasing the intensity of the light didn’t change the energy of the electrons. Einstein reasoned that the electrons must be bound to the atoms of the metal in specific orbits with discrete energies; only a photon with the right amount of energy (i.e., the correct color) could cause the electron to break loose. And, because increasing the light’s intensity increased the number of photons, that also increased the number of electrons. As an unintended side-effect, his paper also laid the groundwork for quantum mechanics – which Einstein hated and spent most of his life trying to find an alternative explanation. It also formed the basis for lasers, which he described in the paper.

But it was the last two papers that really shook the physics establishment.In attempting to explain why Michelson and Morley had failed to discover an ether responsible for the motion of photons, Einstein discovered that the laws of the universe change as one goes very, very fast; he discovered that what happened as relative to the speed of the particle and so established special relativity and declared time to be a fourth dimension. Einstein would later expand the idea so that it included all matter and not just photons; this became known as general relativity.

Not content with changing how we looked at time itself, Einstein went on to show that energy and matter were the same thing in different guises. One could take energy and transform it into matter, for example by using heat to create a photon. And, more importantly, one could take matter and convert it into energy, as happens in fission and fusion reactions.

Needless to say, the scientific establishment didn’t take this well. They determined to prove that Einstein and his strange ideas were wrong. Fortunately, an opportunity soon arose. If special relativity were correct, then the mass of the Sun would warp space around it, causing light to bend. So ans star that was looked at when it was near the Sun would appear to be bent out of position. In 1919, there was a solar eclipse that allowed astronomers to measure the position of the stars in the Hyades constellation. Needless to say, Einstein was proven right.

Because his ideas were still too troubling to bear thinking about, but because they had thus far proven to be correct, Einstein was awarded the 1921 Nobel Prize in Physics for the much less controversial photoelectric effect. Being no dummy, Einstein accepted the prize and ignored the controversy.

If you’d like to try an experiment that shows how relativity affects things in free fall, then try this one from the Secret Science Society:

And if you’d like to help physicists refine Einstein’s ideas, then why not contribute the idle time on your computer with LHC@home?

5 thoughts on “March 14 – It’s All Relative

  1. I never knew that about the Casablanca song. That’s very interesting! Always liked the song, now I like it even more.

    And isn’t it ironic that the scientist whose name is most synonymous with genius (Einstein) was so wrong about a perfectly acceptable branch of physics (quantum mechanics)? Famously wrong, but still famously genius. And poor old Neils, nobody outside of physics even knows his name.

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