Faster than light

Light fascinated me as a child, and I shared all the facts and mysteries with my own kids as well. But as far as I know, none of them followed my lead in trying desperately to conquer it

Reading Time: 4 minutes

Our family has a longstanding relationship with the speed of light. We take care never to exceed it, for one thing. But there’s more than that.

As a kid, I had a lot of light-related fascinations—that light had a speed at all, for starters, and that it was so unimaginably fast, yet also finite and measurable. I learned that the moon was a light-second away, the sun eight light-minutes, and Proxima Centauri, the nearest star, 4.2 light-years. I knew the Milky Way, one galaxy of billions, is 100,000 light-years side to side.

Light helped me finally grasp the real immensity of the universe—and my own infinitesimalitude.

Light is SO much faster than (pfft) sound—almost a million times faster, which is why lightning is already kicking back with a light beer when thunder comes panting up behind.

This stuff gave me endless fodder for discussion on first dates. It also neatly took care of second dates.

Light helped me finally grasp the real immensity of the universe—and my own infinitesimalitude.

When it came time to marry, I limited the pool to those with no more than two degrees of separation from the speed of light. Turns out my college friend Becca attended the same high school as Nobel laureate Albert Michelson, he of the Michelson-Morley experiment, which laid the groundwork for special relativity by showing that light weirdly measures at the same speed even if you are moving rapidly toward or away from the source.

Becca and I were married in a San Francisco Lutheran church with You-Know-What streaming through the windows. Coincidence?

Our kids picked up the thread. As we drove home from his football practice years ago, Connor (then 12) asked why time slows down as you go faster. The previous week we had discussed the very cool Hafele-Keating experiment in which cesium clocks flown around the world differed from identical clocks on the ground by a few nanoseconds. (I think I spotted the exact moment during practice when he was thinking about Hafele-Keating instead of Offensive-Lineman.)

I said at the time that our velocity through space plus our velocity through time equals the speed of light, so the faster you go through space, the slower you necessarily go through time.

In less than five seconds, he said, “So light doesn’t experience time, then.”

Holy buckets. I’d never thought of it.

A few years later, standing with his then-nine-year-old sister Delaney in the dark, waiting for the school bus, I discovered that I’d never shared the insanely cool fact that many of the stars we see aren’t there anymore. Some may have blinked out centuries ago, but the end of the column of photons, even at 186,000 miles a second, still hasn’t reached us. Tomorrow morning we might suddenly see a “new,” bright star in the sky, which is actually a nova that happened millions of years before. That’s what nova literally means, a new star. But it isn’t really being born—it’s dying.

She made all those astonished, comprehending sounds I’d come to love. I quickly re-combed her hair as the bus pulled up.

Around the same time, on the heels of the announcement that the speed of light might have been exceeded by neutrinos at CERN, my wife took the opportunity to give her second graders a little insight into how science works. “All these years we thought light was the fastest thing possible,” she said. “Even Albert Einstein said that was true. Now maybe, just maybe, scientists have found that it’s possible for something to go even faster. First they have to test and test again to be sure, and if it is, they’ll say, ‘Wow, we were wrong. We have to change our minds.'”

It’s true that we’re capable of upending our Newtons and Einsteins when the evidence insists, but it doesn’t happen as gladly as we sometimes pretend. Individual scientists are just as prone as the rest of us to kick and scream and bite to protect their favorite conclusions, until the collective enterprise of science itself busts them upside the head. The important message for these second graders, though, is that science contains the ability, the means, even the willingness to change its conclusions in light of new evidence, despite whatever preferences individual scientists might have. (The CERN scientists assumed they made an error in measurement, by the way, something that has happened before—and researchers in the Netherlands subsequently found the error, a correction confirmed by four other teams. Einstein, for the moment at least, is right again.)

All this light conversation brought me back to experiments I conducted when I was about seven years old, just inside my front door in St. Louis, Missouri. The edge of the glass on our front storm door was beveled, which formed a little prism, which at a certain time of day threw a tiny, intense rainbow on the floor.

I decided I was going to catch that rainbow. In a shoebox.

In what may be the perfect illustration of a seven-year-old mind, I knew that light was the fastest thing in the universe, which meant I would have to be super fast to beat it.

I found a shoebox and held it above the rainbow. I slowed my breathing, concentrated…then CLOMP! brought the box down on the rainbow.

Too slow. The damn thing was on top of the box.

In what may be the perfect illustration of a seven-year-old mind, I knew that light was the fastest thing in the universe, which meant I would have to be super fast to beat it.

I’d do this for a good half hour at a time before giving up, but only for that day. I was back at it the next day at exactly the same time, when the window-prism once again caught the sun at just the needed angle. I kept up the experiment for long enough to eventually notice that the time was not exactly the same each day, and there was a new thing to wonder about.

I remember thinking maybe light is a little slower in the winter, and that’s why it’s colder then. So I tried again in January. But even with its winter boots on, light was always just a liiiittle faster than I was, and the rainbow appeared on top of the box.

Eventually my dream of catching the rainbow went the way of so many others. But those experiments at CERN give me hope. Maybe I just need a box made of neutrinos, and I’m back in the game.

Dale McGowan is the author of Parenting Beyond Belief, Raising Freethinkers, and Atheism for Dummies. He holds a BA in evolutionary anthropology and a PhD in music.