The Father of Modern Physics
By Matt McKeown
Einstein's theories can sound like an avalanche of weirdness for its own sake. The truth is simpler, and more interesting.
If any name on our author bank is synonymous with scientific genius, it is Albert Einstein. One of the seminal intellects of the twentieth century (which was arguably a decent hundred years for science), Einstein rewrote the very laws of physics. Space could bend; time, dilate; matter, collapse to a mathematical point. The concepts themselves are dizzying. It’s tempting to look backwards and say, in the words of The Book of the Dun Cow, “In those days the earth was still fixed in the absolute center of the universe. It had not yet been cracked loose from that holy place, to be sent whirling—wild, helpless, and ignorant—among the blind stars.” But it would be a mistake not to appreciate that Einstein’s, too, is a glittering universe.
Einstein gained notice in the academy in 1905 with four prominent scientific papers, two of them on ideas he was the first to propose: the theory of special relativity and mass-energy equivalence. In 1933, he came to the United States, and taught at Princeton until his death in 1955.
Most of us have a vague knowledge of Einstein’s work from grade school and pop culture allusions—something about E = mc2, and black holes, and putting twins on rockets to make them different ages. These concepts are of course both obvious and practical. Still, I hope the reader will bear with me if I explain a little. There is a lot of Einstein to choose from; let’s focus on just one thing, special relativity.
Relativity is a theory about frames of reference. Although applying the theory usually involves a lot of complex math, the core concept is really quite simple: some things look different depending on (or relative to) where you’re standing, while other things look the same regardless. Einstein’s brilliance lay in applying this familiar principle in a new way: not only space, but motion and even time itself, are relevant parts of our frame of reference. In physics, some things can “look” different depending on whether we are moving (relative to the thing in question), in what direction, and how quickly—and one of these things is the passage of time. And on the other hand, some things do “look” the same no matter what. One of those things, according to Einstein’s theory, is the speed of light.
This has some fascinating implications. Let’s imagine two planets that both get hit by asteroids. An observer standing on one planet sees both impacts happen at the same time. But another observer, in a rocket traveling past the planets at one-third the speed of light, distinctly sees the impacts happen at different times. Which observer is correct? Well, both are, if we remember to adjust for their different frames of reference. (The adjustment is something called a Lorentz transformation, but we can’t stop to explain the details.) It’s a little bit like hearing a fire truck siren zoom past you on the sidewalk: it goes from a high pitch to a much lower one to you, even though a person riding the truck would not hear any difference. It turns out, based on Einstein’s theory, that our perception of time can be “stretched” in much the same way our perception of sound waves can—albeit through a very different mechanism.
Now, an observer would need to travel at a sizable fraction of the speed of light to notice time dilation between events. And even then, the distance required to observe it would be hundreds of thousands of miles. So special relativity doesn’t show up in our lives, right? Wrong! You probably have something with you right now that depends on special relativity to work: your phone.
One of the standard features of modern phones is GPS, which relies on satellites. In order to calculate distances and times correctly from their own rapidly moving frame of reference, these satellites have to take relativity into account; if they didn’t, their measurements would be off by a factor of ten every day. In other words, the 32 mile drive from DC to Annapolis would, the next day, show up as a 320 mile drive, the distance from DC to Detroit. Correcting based on special relativity allows GPS satellites to stay reliable twenty-four hours a day, all over the world (leaving us with only the maps themselves to blame for getting us lost).
The theory of relativity has had an impact on philosophy and culture as well. In some ways, it aligns with the literary ideas of the postmodern movement: both Einstein and some postmodernists were interested not in abolishing the idea of truth, but in examining the frames of reference we use to understand truth—with the ultimate purpose of knowing more about reality, not less. Of course, plenty of people who understand neither physics nor literary theory will freely misuse both. It is a lot easier to throw around a phrase like “It’s all relative” to sound intelligent, than it is to perform Lorentz transformations. But these misuses do not change the fact that Einstein’s vision of the universe is both surprisingly useful and weirdly fascinating.
Aristotle opened his Metaphysics with the statement “All men by nature desire knowledge.” If you find yourself desiring more knowledge on this particular topic, the YouTube channel Minute Physics has an eight-part series of short videos explaining special relativity in greater depth (the series as a whole clocks in at a little less than an hour). We also published a student essay a while back on the black hole information paradox, another indirect descendant of Einstein’s work.
Every week, we publish a profile of one of the figures from the CLT author bank. For an introduction to classic authors, see our guest post from Keith Nix, founder of the Veritas School in Richmond, VA.