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There was physics before Einstein in the same way that there was biology before Darwin. Einstein didn’t just add some new ideas to physics. And he didn’t just add a unifying framework for doing physics, like Newton. Einstein took what people thought was physics, turned it upside down, then turned it inside out.


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There was physics before Einstein in the same way that there was biology before Darwin.  Einstein didn't just add some new ideas to physics, and he didn't just add a unifying framework for doing physics like Newton.

Einstein took what people thought was physics, turned it upside down, and then turned it inside out.

In the same way that Darwin's work made people see life itself differently, Einstein's work made humanity reexamine time and space.

The classical worldview associated with names you know, like Euclid, Aristotle, and Newton held that the rules governing space and time were absolute.

One meter was always one meter long.  One hour would always be one hour long.  Matter was made up of immutable and indivisible atoms.  And energy moved through a medium called ether because everything had to move through something, right?

God wouldn't just make, I don't know, a howling void.

And with new disciplines like thermodynamics and fun applications like steam power and light bulbs, human understanding of the fundamental forces of nature seemed pretty solid.

To quote historian of science (?) , by 1900, "Physics was perceived by many to be an almost completed discipline."  

But within this almost completeness lurked many unanswered questions.

One of the biggest was the failure of the Michelson-Morley experiment in 1887.  They'd attempted to demonstrate that the speed of light changed just a little when measured from the earth, which is always moving, relative to the ether, which never moves.

But despite meticulous efforts, they couldn't find any slowing down.  Light moved at a constant speed, almost as if there was no ether.

Then there was the electron and radioactivity.  In 1897, English physicist J.J. Thompson showed that cathode rays were made up of discrete particles way smaller than whole atoms - electrons.

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And around the same time, Marie Curie proposed a theory of radioactivity, which classical physics didn't predict.

Then, in the early 1900s, Ernest Rutherford experimented on radioactive decay.  He named radioactive alpha, beta, and gamma particles, classifying them by their ability to penetrate different kinds of matter.

And Henri Becquerel measure beta particles and realized they were actually electrons exiting the nuclei of atoms at high speeds.

So by the early 1900s, radioactive decay was understood, and the crisis of the immutable atom was as deep as the crisis of the ether.

A bunch of people were investigating Maxwell's equations and looking at black-body radiation, or the heat emitted by dark objects when they absorb light.

Then Heinrich Hertz, the original radio wave guy, discovered the photoelectric effect, or the paradox that certain metals produce electrical currents when zapped with wavelengths of light above a certain threshold.

Things started to get messy.  Energy was thought to be a continuous wave, but according to wave-based theory, there might be infinite energy radiated back by black bodies zapped with certain wavelengths.

This seemingly violated the newly established laws of thermodynamics, like, infinite energy doesn't seem right.

So in trying to explain the weird results about light and heat, German physicist Max Planck theorized that light may not be a wave after all, but a series of particles or quantum units - all very non-classical.  Sorry Aristotle.

Check out Crash Course physics for more on, uh, the quantum weirdness here.

Enter: Albert.  Einstein was born in 1879 and grew up in southern Germany, Italy, and Switzerland.

He dropped out of high school, then studied to teach physics and math and became a Swiss citizen.  But he couldn't get a teaching job because he was Jewish.

So in 1901, he took a job at the patent office and started a PhD at the University of Zurich, which he finished in 1905.  You're gonna wanna remember that year, 1905.

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Now, Al was not an academic hotshot or a self-funded amateur, he was a working-class nobody who did physics on the side.  But he was also a patent officer who spent his days poring over technical documents.

He was an outsider obsessed with math because math is beautiful, and yet he was a deeply practical person who believed that good math and science could be communicated plainly.

Plus, he was young and bold, and he had a super smart and supportive first wife, Serbian mathematician Mileva Maric.  So the year he finished his PhD, 1905, Al published his dissertation and four papers that changed physics overnight.  This was his annus mirabilis, or miracle year - like 1666 had been for Newton.

Help us out, thought bubble.

At age 26, Einstein published revolutionary work on 1. Brownian Motion, or the random motion of particles in fluids, 2. The Photoelectric Effect, supporting the idea of energy as a series of particles, not a wave, 3. the Equivalence of Mass and Energy, and 4. Special Relativity.

Special Relativity, especially, made Einstein a scientific rock star.  He proved that nothing can move faster than light.  This explained why Michelson and Morley hadn't observed light slowing in ether.  And a lot of other things.

Einstein got rid of all reference frames for space and time.  There was no longer some universal space in which physics happened.  All measurements became relative to the position and speed of the observer.

Space and time became one mathematically continuous space-time.  So an event at one time for observer A could take place at a completely different time for observer B.

And the only constant in the entire system became the speed of light - which classical physics predicted could change!

From special relativity followed the equivalence of mass and energy proof, which was also mind-blowing.  It's probably the most memorable physics formula ever, since it's printed on mugs and t-shirts the world over.

E=mc^2, or energy equals mass times the speed of light squared.  Or mass and energy can be converted into one another.

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