I’m a humanities guy, but I’ve never lost my childhood love of math and science. I’m looking forward to the Large Hadron Collider being fired up next year the way normal male Americans look forward to the NBA playoffs. I like to be an informed fan, and since Einstein is the Michael Jordan of scientists, I wanted to know what it is exactly that he figured out, and why it’s so important. Beyond the physics, I wanted to know what put Einstein into the pop pantheon alongside Bob Marley and John Lennon. You never see dorm room posters of Henry Clerk Maxwell or Neils Bohr. The only other scientist who comes remotely close in pop stature is Darwin, but aside from his dramatic beard, Darwin the person doesn’t register much beyond his theories. Why is Einstein such a rock star?
Let’s start with the face. Einstein’s iconic white hair and wrinkles coexisted with an unusually childlike face. Einstein had large, widely-spaced eyes on a large head. The combination of infantile and ancient is psychologically intense. I wasn’t surprised to find out that Einstein’s face inspired the design of Yoda and ET.
Einstein’s parents worried about his intellectual development as a child. He didn’t start speaking until he was three, and he wasn’t completely fluent until nine. A picture emerges of an eccentric and inward kid, with a lot of attention devoted to his own imagination and thoughts, and not much attention left over for everything else. I don’t believe that Einstein was born with a superior brain. His spectacular spatial reasoning and mental imaging abilities came at the expense to his social skills and his personal happiness. History remembers his achievements and tends to gloss over his failed marriage and depression.
Einstein loved to tell the story of being five years old and being shown a small pocket compass by his father. He was elated to discover that something in “empty” space acted on the needle. Einstein would later describe his first brush with the Earth’s magnetic field as one of the most revelatory events of his life. As a kid, he built models and mechanical devices for fun, and he showed mathematical ability early on. In 1891, he taught himself Euclidean geometry from a school booklet (for fun, whee!) and began to study calculus. The teenage Einstein sounds like the consummate math nerd, antisocial and hostile to authority. He only completed one term of the equivalent of high school before dropping out in the spring of 1895.
Einstein’s family was Jewish, but not observant, and he went to a Catholic elementary school. I’m guessing that the contradictions he experienced there were a source for his later outspoken secular humanism.
The same year he dropped out of school at age sixteen, Einstein performed a famous thought experiment with the speed of light. He was trying to wrap his head around one of his era’s most baffling scientific problems. There were these equations, the Maxwell equations, that describe electricity and magnetism extremely accurately. The equations predict that the speed of the light (around 667 million miles per hour) is always the same, regardless of how fast you’re moving when you observe it. If you’re sitting still and you turn on your flashlight, the light zips away from you at 667 million mph. No mystery there. But the Maxwell equations say that if you’re zipping along in a spaceship at 666 million mph and you turn on your headlights, the beams will still race away in front of you at 667 million mph. Scientists in 1895 were making the first really accurate measurement of the speed of light under various conditions, and they were hoping to prove this prediction wrong. Much to their horror, every experiment proved the Maxwell equations right. Einstein was trying to figure out a way out of the paradox by imagining himself to be in that spaceship and turning on your headlights.
Like a lot of scientists, Einstein was a musical person. He frequently used musical terms to express physics concepts. At the insistence of his mother, he took classical violin lessons as a kid, and like most people, disliked them and eventually stopped them. Like dishearteningly few people, Einstein returned to music in adulthood, and became a dedicated amateur classical violinist.
He once said:
If I were not a physicist, I would probably be a musician. I often think in music. I live my daydreams in music. I see my life in terms of music.
Einstein eventually attended university, where he studied math and science in the hopes of getting a science teaching gig. He managed to graduate, but his antagonistic relationship with his professors didn’t help with recommendations or job offers. Instead, the father of a classmate helped him get an unglamorous position as an assistant examiner at the Swiss patent office. It turned out to be a good day job for him. The pace was undemanding and it gave him the opportunity to ponder his favorite subject, the electromagnetic force, at length.
Here’s a fun Java applet that lets you play with a simulated electromagnetic field. We take the field’s physicality for granted in modern life, since we’re always walking through metal detectors and such, but a hundred years ago you could have been forgiven for doubting that such a weird idea could possibly be true. The field concept is not an easy one, and if we weren’t intimately familiar with evidence of its existence, it might sound like a paranoid delusion. The math isn’t much help in making fields more accessible to our common sense, because it requires frightening calculus. It’s humbling to consider Einstein trying to puzzle through electromagnetism for fun while he worked his slacker job in the earliest years of the twentieth century.
During 1905, in his spare time and sometimes during work when no one was looking, Einstein wrote four short articles for publication in Annalen Der Physik, then the leading journal in the field. He wrote them without much scientific literature to refer to or many fellow scientists to talk with. The only science library in town was closed on his only day off. People call them the Annus Mirabilis papers, from Latin for ‘miracle year.’
The first Annus Mirabilis paper was titled On A Heuristic Viewpoint Concerning The Production And Transformation Of Light. (Heuristic means hands-on or practical.) It was a response to Max Planck’s hypothesis that energy comes bundled in tiny little discrete chunks or particles called quanta (singular quantum.) Einstein’s key contribution was to say that energy quantization is a general, intrinsic property of all other electromagnetic energy, not just light. He showed how these little chunks of energy are mathematically related to the energy’s frequency. This later developed into the concept of photons. So that’s the first paper.
Einstein’s second article of 1905 was called On the Motion, Required by the Molecular Kinetic Theory of Heat, of Small Particles Suspended in a Stationary Liquid. It covered his study of Brownian motion, the random jostling of dust motes in the air, or the swirling of milk in coffee. Einstein used mathematical analysis of Brownian motion to provide empirical evidence for the existence of atoms. Before this paper, atoms were recognized as a useful concept, but physicists and chemists debated whether they were real things or just mathematical abstractions. Einstein’s statistical discussion of atomic behavior gave experimentalists a way to count atoms by looking through an ordinary microscope.
The third paper was called On The Electrodynamics Of Moving Bodies, and it introduced the special theory of relativity, of which you have probably heard but whose content is probably mysterious to you. It was to me until I started reading Brian Greene books. Relativity is extremely tripped out. Remember how the velocity of light is supposed to be the same, regardless of how fast you’re moving when you measure it? Einstein interpreted this wildly counterintuitive fact as evidence that everything is always moving through space and time at the speed of light. More accurately, everything in the universe is always moving along the three spatial dimensions and the fourth dimension of time at the velocity of light. Whatever your velocity through space is, your velocity through time is the difference between it and the velocity of light. The faster you move through space, the slower you move through time. The slower you move through space, the faster you move through time. No joke. For a photon zipping along through space at the speed of light, time isn’t passing at all.
So if the theory of relativity is true, and every experiment confirms that it is, why hadn’t anyone noticed before 1905? It’s mostly an accident of scale. We and most of the things we encounter in the world move through space a lot slower than 667 million miles an hour, and by cosmic scales we can only change our velocity by miniscule amounts, so our movement through time is barely affected. It’s like the way the curvature of the earth appears to be zero when we’re standing on it, because it’s so much bigger than we are. We would have found out the earth was round much sooner if it was only twenty-seven miles wide instead of twenty-seven thousand. Time dilation is trivial for our poky selves, but it’s a real fact of the universe. It has more serious consequences at higher speeds and energy levels, and larger time and distance scales. Global positioning systems have to account for time dilation between the different satellites as they hurtle around their orbits.
Heavy, right? It gets better (or worse, depending on your tastes.) Brian Greene asks us to imagine the universe as a loaf of bread arranged along the time axis, where each slice is a freezeframe snapshot of everything in space at a particular moment in time. If you and someone else are moving relative to one another, you slice the spacetime loaf at different angles. Here on Earth, the difference in angle between my spacetime slices and yours are imperceptibly tiny. But what a photon or a person on a far-distant planet considers to be the state of the universe “now” is going to be very different. Quoting Brian Greene, italics his:
If you buy the notion that reality consists of the things in your freeze-frame mental image right now, and if you agree that your ‘now’ is no more valid than the ‘now’ of someone located far away in space who can move freely, then reality encompasses all of the events in spacetime. The total loaf exists. Just as we envision all of space as really being out there, as really existing, we should also envision all of time as really being out there, as really existing too. Past, present and future certainly appear to be distinct entities. But as Einstein once said, “For we convinced physicists, the distinction between past, present and future is only an illusion, however persistent.”
My first exposure to this idea was from Kurt Vonnegut in Slaughterhouse-Five. The Tralfamadorans explain to Billy Pilgrim that humans perceive time “passing” the way we’d perceive a landscape passing if we could only see it through a long cardboard tube while being carried along on rails.
In this way of thinking, events, regardless of when they happen from any particular perspective, just are. They all exist. They eternally occupy their particular point in spacetime. There is no flow… It is tough to accept this description, since our worldview so forcefully distinguishes between past, present and future. But if we stare intently at this familiar temporal scheme and confront it with the cold hard facts of modern physics, its only place of refuge seems to lie within the human mind.
I’m a little disturbed by BG’s confrontational tone – “confront”, “cold hard facts”, “place of refuge” — but let’s bracket that and move on.
The feeling that time flows is deeply ingrained in our experiences and thoroughly pervades our thinking and language… But don’t confuse language with reality. Human language is far better at capturing human experience than at expressing deep physical laws.
Does time have an arrow discernible somewhere in the universe outside our collective imaginations? Intuition says yes, since spilled milk doesn’t unspill. But the basic physics equations don’t specify a direction for time or depend on any asymmetry to it. Post-Einstein, you can treat time as just another direction, like left-right, up-down, forwards-backwards. Equations describing the moon’s orbit or electrons in a molecule have time-reversal symmetry. In theory, you could manipulate the particles into unspilling your milk; it would just be very very difficult, and it’s vanishingly unlikely to ever just happen by itself.
Maybe time’s arrow is just our interpretation of the strong overall tendency towards entropy in the world around us, not a fundamental fact of the universe. The Wikipedia article on time says:
Psychological time is, in part, the cataloguing of ever increasing items of memory from continuous changes in perception. In other words, things we remember make up the past, while the future consists of those events that cannot be remembered. The ancient method of comparing unique events to generalized repeating events such as the apparent movement of the sun, moon, and stars provided a convenient grid work to accomplish this. The consistent increase in memory volume creates one mental arrow of time. Another arises because one has the sense that one’s perception is a continuous movement from the unknown (Future) to the known (Past). Anticipating the unknown forms the psychological future which always seems to be something one is moving towards, but, like a projection in a mirror, it makes what is actually already a part of memory, such as desires, dreams, and hopes, seem ahead of the observer.
Okay. So Einstein’s third paper of 1905 undermined the concept of time. His fourth one was called Does The Inertia Of A Body Depend Upon Its Energy Content? From relativity, Einstein showed how one can deduce the famous equation showing the equivalence between matter and energy, E=mc^2. To get the energy equivalence (E) of some amount of mass (m), you multiply the mass by the velocity of light (c), and then you multiply it by the velocity of light again. A very small amount of mass converts to a very large amount of energy. When hydrogen in the sun fuses into helium, part of its mass gets converted to the energy we receive here on Earth.
If Einstein had been hit by a bus in 1906, we’d still be absorbing his output, but there was more big stuff coming. In 1909, he presented a paper called The Development Of Our Views On The Composition And Essence Of Radiation. In this and an earlier 1909 paper, Einstein showed that the energy quanta introduced by Max Planck also carry a well-defined momentum and act in many respects as if they were independent, point-like particles. This paper marks the introduction of the modern photon concept (although the word itself was coinedÂ later). Being able to mathematically describe and predict the behavior of photons has made possible such modern conveniences as computers, TV and supermarket scanners. The behavior of photons suggests more deep weirdness going on behind the world we experience. Einstein showed that light, like all other forms of mass-energy, must simultaneously behave like both a wave and a particle, a revolutionary idea at the time and still a major head-scratcher.
In November 1915, Einstein unveiled his new theory of gravity, the general theory of relativity. In general relativity, gravity is no longer a force, as it is in Newton’s conception of gravity. Instead, gravity is the warping of spacetime by matter and energy. Empty space itself is the thing being warped in general relativity. As with relativistic time dilation, this warping is a real thing. We don’t notice it because of the scale thing. If there’s a huge amount of mass-energy, spacetime can get stretched like silly putty. You can see it in Hubble Space Telescope photos of very distant galaxies.
General relativity laid the theoretical framework for the big bang theory.
Einstein’s career from 1905 to 1917 was a lot like Paul McCartney’s from Please Please Me through Abbey Road. Einstein’s career after he moved to New Jersey was more like McCartney from Wings through the present: he was a highly visible figure on the landscape, but he didn’t produce any new ideas that anyone cared about. Mathematicians and scientists, like rock stars, are famous for burning out young. Einstein the scientist burned bright and fast, and then coasted amiably along to old age. But Einstein the political figure was just coming into full flower. His authority problems as a kid turned into a principled opposition to fascism and violence as an adult. He was a member of the Rationalist Press Association and an admirer of Ethical Culture. On the much-contested subject of his religious views, here’s what the man himself had to say:
A human being is part of a whole, called by us the Universe, a part limited in time and space. He experiences himself, his thoughts and feelings, as something separated from the rest–a kind of optical delusion of his consciousness. This delusion is a kind of prison for us, restricting us to our personal desires and to affection for a few persons nearest us. Our task must be to free ourselves from this prison by widening our circles of compassion to embrace all living creatures and the whole of nature in its beauty.
He published a paper in Nature in 1940 called Science And Religion:
A person who is religiously enlightened appears to me to be one who has, to the best of his ability, liberated himself from the fetters of his selfish desires and is preoccupied with thoughts, feelings and aspirations to which he clings because of their super-personal value … regardless of whether any attempt is made to unite this content with a Divine Being, for otherwise it would not be possible to count Buddha and Spinoza as religious personalities. Accordingly a religious person is devout in the sense that he has no doubt of the significance of those super-personal objects and goals which neither require nor are capable of rational foundation…In this sense religion is the age-old endeavor of mankind to become clearly and completely conscious of these values and goals, and constantly to strengthen their effects.
The religious and atheistic alike claim him as a hero, but I think if he had to pick a side, he would have come down closer to Darwin and Dawkins:
If something is in me which can be called religious then it is the unbounded admiration for the structure of the world so far as our science can reveal it.
You will hardly find one among the profounder sort of scientific minds without a peculiar religious feeling of his own. But it is different from the religion of the naive man.
For the latter God is a being from whose care one hopes to benefit and whose punishment one fears; a sublimation of a feeling similar to that of a child for its father, a being to whom one stands to some extent in a personal relation, however deeply it may be tinged with awe.
But the scientist is possessed by the sense of universal causation. The future, to him, is every whit as necessary and determined as the past. There is nothing divine about morality, it is a purely human affair. His religious feeling takes the form of a rapturous amazement at the harmony of natural law, which reveals an intelligence of such superiority that, compared with it, all the systematic thinking and acting of human beings is an utterly insignificant reflection.
I believe in Spinoza’s God, who reveals Himself in the lawful harmony of the world, not in a God who concerns Himself with the fate and the doings of mankind.
In 1939, Einstein sent a letter to Franklin Delano Roosevelt urging the study of nuclear fission for military purposes, for fear that the Nazis would develop nuclear weapons first. The letter prompted an investigation that eventually led to the Manhattan Project. Einstein himself didn’t end up working on the bomb, and, according to Linus Pauling, he later regretted having written his letter. Einstein considered himself a pacifist and humanitarian, and in later years, a committed democratic socialist.
I believe Gandhi’s views were the most enlightened of all the political men of our time. We should strive to do things in his spirit: not to use violence for fighting for our cause, but by non-participation of anything you believe is evil.
Einstein was a busy civil rights agitator, and a member the Princeton chapter of the NAACP. With Paul Robeson, he was a co-chair of the American Crusade To End Lynching. When the octogenarian WEB DuBois was frivolously charged with being a communist spy, Einstein volunteered as a character witness in the case, which led to the charges being dismissed. Maybe the biggest compliment America ever paid Einstein was the size of his FBI file: fourteen hundred pages on his activities and movements. The FBI recommended that Einstein be barred from immigrating to the United States under the Alien Exclusion Act, alleging that he “believes in, advises, advocates, or teaches a doctrine which, in a legal sense, as held by the courts in other cases, ‘would allow anarchy to stalk in unmolested’ and result in ‘government in name only.’” Israel offered Einstein the presidency, and he turned it down. He was a supporter of Zionism in the cultural sense but he had some reservations about its nationalistic aspect. In a speech he said:
My awareness of the essential nature of Judaism resists the idea of a Jewish state with borders, an army, and a measure of temporal power, no matter how modest. I am afraid of the inner damage Judaism will sustain.
Anytime I did something dumb in grade school, my friends would say sarcastically, “Nice going, Einstein.” Since then I’ve said it myself more times than I can count. Einstein serves a handy shorthand for the natural genius, the superhuman intellect. He offers the hope that any lazy and undisciplined student might secretly be a genius, one in a zillion. This fantasy isn’t as far-fetched as it seems. People like Einstein aren’t necessarily well-served by the way our society requires us to learn. Sitting at desks in big groups just does not work for all kids. Kids learn a lot from school, but they don’t necessarily learn math and science, they just learn how to pretend to be attentive while managing a lot of boredom.
Einstein donated his brain to science upon his death, and there has been a whole ghoulish cottage industry around its study. Steven Pinker’s theory on Einstein’s brain is that it showed rapid prenatal development of areas of the brain responsible for spatial and analytical reasoning which, in competing for finite bodily real estate, temporarily robbed resources from functions of the brain responsible for speech development. Pinker and others have extended this speculation to explain the development of other famously gifted late-talkers, including mathematician Julia Robinson, pianists Arthur Rubinstein and Clara Schumann, and physicists Richard Feynman and Edward Teller. These people were also said to have shared several of Einstein’s childhood peculiarities, like monumental tantrums, rugged individualism and highly selective interests. Whether or not this is true, it fits well with my larger hypothesis that a genius is basically an obsessive-compulsive who’s lucky enough to be obsessed with something constructive.
By the way, I didn’t have a poster of Einstein in my dorm room, but as an adult I’m proud to have an Einstein action figure sitting on the shelf, above my computer, next to my clock.