Michael Gerson: The return of the unseen
WASHINGTON—Each of the GPS satellites that allow me to navigate to a new restaurant carries an atomic clock that needs to be accurate in order to triangulate the speed and position of my moving car. But there are a couple of problems. Einstein’s Theory of Special Relativity predicts that clocks hurtling through space at satellite speed will appear to tick more slowly than earthbound clocks by about 7,000 nanoseconds each day (a nanosecond is a billionth of a second). General Relativity, on the other hand, predicts that clocks farther from a massive object (the earth), will advance faster than clocks on the ground, in this case by a little more than 45,000 nanoseconds.
If the GPS system fails to compensate for the 38,000-nanosecond difference predicted by an eccentric German physicist, errors in global positioning would increase by about 10 kilometers each day. In 23 days, my restaurant in Washington, D.C., might mistakenly show up in Philadelphia. This is the oddness of modern physics invading the everyday world.
Everyone needs a diversion, even from a job they love. My escape from a political world in which Ted Nugent figures prominently (or at all) is to read books on cosmology and quantum theory and then bore my family with scientific trivia. Note that reading is different from understanding. Being mathematically illiterate, I tend to skip the equations, which is like reading music without comprehending the notes. But I understand enough to know that physics, unlike politics, is experiencing a Golden Age. Microwave receivers detect small variations in the cold, ancient light from the Big Bang. Vast, underground colliders produce elegantly curved sprays of exotic particles.
Revolution has followed revolution. At the macro level, it was only in the late 1990s that astronomers found, against all expectation, that the expansion of the universe is accelerating instead of slowing down. This led to the postulation of an unseen dark energy in the vacuum of space—a force from the void capable of repelling galaxies. Astronomers have also found that stars on the edges of galaxies move faster than gravitational theory would predict, leading to the theory that (so far) undetectable dark matter keeps galaxies from flinging apart. It is estimated that more than 95 percent of the universe—dark energy plus dark matter—is entirely unseen.
The micro level is even odder. A century of quantum physics still has not fully sunken in. The smallest particles do not exist in places, but in probability waves that reach across the universe. In the prevailing (but disputed) consensus, they gain a definite position only upon observation. According to Brian Cox and Jeff Forshaw in “The Quantum Universe,” we inhabit “a world in which a particle really can be in several places at once and moves from one place to another by exploring the entire universe simultaneously.”
At every level, from top to bottom, we only gain knowledge of the world by cutting our ties to common sense and intuition. The largest things are hidden from our view. The smallest things defy any coherent mental picture. There is, in fact, a strangeness at the heart of all things.
What are the philosophic implications? Such deep-down contingency does not, for example, prove or disprove theism. But modern physics leaves room for a reality beyond our senses. In the tame, orderly world of Isaac Newton, the motion, position, past and future of every particle, person or planet were predictable and determined. Compare this to Max Tegmark’s brilliant, outlandish new book, “Our Mathematical Universe,” in which the author argues that probability waves, instead of collapsing, branch off into parallel universes—meaning you and I do as well. He further claims that our external reality is not only described by math, it is actually a mathematical structure—leaving those of us who are mathematically challenged incapable of speaking our mother tongue.
The point here is not that Tegmark’s theories are broadly accepted, only that such theories are no longer considered absurd. Physics has seen the return of the unseen—parallel universes, infinitesimal strings, floating and colliding branes—that are reasonably inferred without being physically observed. I can think of other creative forces in that category. Not for centuries has physics been so open to metaphysics, or more amenable to an ancient attitude: a sense of wonder about things above and within.