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On The Physics and Philosophy of Time 5 min read

On The Physics and Philosophy of Time

By Cary Littlejohn

I’m not sure what was in the air in mid-December, but I belatedly came across two references to time.

That’s a slightly odd-feeling sentence, and it’s because of the many and varied ways we use “time” in everyday speech; it feels like I’m cutting off the end of a sentence, perhaps, or that I’m a a bit confused and speaking imprecisely.

But the sentence is correct as written: The pieces — one written, the other a podcast — are about the concept of time. And if you thought that sentence felt weird, hoo boy, are you in for a treat if you choose to dig into these two pieces.

The podcast just addresses it right there in its title: Time Is Way Weirder Than You Think.

It’s this interesting mix between hard-and-fast physics and the philosophical. The reality of time versus the feeling of time. It’s ever-presentness versus its human social construct-ness.

From the podcast’s show notes, here’s a brief overview of what the conversation includes:

It’s not an exaggeration to say that “clock time” runs our lives. From the moment our alarms go off in the morning, the clock reigns supreme: our meetings, our appointments, even our social plans are often timed down to the minute. We even measure the quality of our lives with reference to time, often lamenting that time seems to “fly by” when we’re having fun and “drags on” when we’re bored or stagnant. We rarely stop to think about time, but that’s precisely because there are few forces more omnipresent in our lives.

“You are the best time machine that has ever been built,” Dean Buonomano writes in his book [“Your Brain Is a Time Machine: The Neuroscience and Physics of Time.”]( Buonomano is a professor of neurobiology and psychology at U.C.L.A. who studies the relationship between time and the human brain. His book tackles the most profound questions about time that affect all of our lives: Why do we feel it so differently at different points in our lives? What do we miss if we live so rigidly bound to the demands of our clocks and appointments? Why during strange periods like pandemic lockdowns do we feel “lost in time”? And what if — as some physicists believe — the future may already exist, with grave implications for our ability to act meaningfully in the present?

We discuss what time would be in an empty universe without humans, why humans have not evolved to understand time the way we understand space, how our ability to predict the future differs from animals’, why time during the Covid lockdowns felt so bizarre, why scientists think time “flies” when we’re having fun but slows down when people experience near-death accidents, what humans lost when we invented very precise clocks, why some physicists believe the future is already determined for us and what that would mean for our ethical behavior, why we’re so bad at saving money, what steps we could take to feel as if we’re living longer in time, why it’s so hard — but ultimately possible — to live in the present moment and more.

The NPR article, which was published just three days before the podcast interview, also has an engaging headline: Researchers say time is an illusion. So why are we all obsessed with it?

It’s much more a two-part analysis, the second of which deals with a lot of the conversations had between Ezra Klein and Dean Buonomano. There is talk of time stretching and slowing down due to Einstein’s general theory of relativity.

But the beginning of the NPR article deals with the incredibly technical and complex process by which we keep time now that we humans have invented it.

Did you know about the National Institute of Standards and Technology (NIST)? It’s located in Boulder, Colorado, and it’s literally where our collective time is kept.

From the article:

To get a sense of where the rigid time that governs most of our lives comes from, Sherman takes me into a beige-colored laboratory crammed with experimental equipment and computers. There are three big boxes looming above lab benches, holding three high-precision atomic clocks. Each box is labeled with a name: One’s called George, another Fiona, and the third is Elvis.

“They all have quirks and personalities,” Sherman explains. “When they fail at 2 a.m. you want to have a little bit of compassion for them, so you give them names.”

George, Fiona and Elvis are just part of the 21-clock ensemble NIST uses to generate the official time. These three clocks tick using hydrogen atoms. The atoms are excited using radiofrequency energy and then sent into a chamber. Once inside, they decay, emitting a specific frequency of light.

Think of it as striking an atomic tuning fork, Sherman says.

The excited hydrogen emits “a tone of light,” he says. The rest of the clock “is an instrument that tries to sample — tries to listen — to a little bit of that light and count the cycles of oscillation in that light.”

Those light cycles are the “tick” of the clock. By averaging a subset of the 21 clocks together, NIST has created a system that can count the time to within one quadrillionth of a second. That means the government’s clock can keep time to within a second over the course of about 30 million years.

In another room, that timing signal is sent out across the United States, and via satellite to other government laboratories in other parts of the world with clocks of their own.

It’s an impressive system, but there’s a catch. You’ve got to keep counting. If you stop, if you blink, you don’t know the time anymore.

“In exchange for this wonderful idea,” Sherman says, “you’re now beholden to count forever and not lose track.”

If I’d found these as soon as they were published, I feel confident in saying they would have found me in a somewhat contemplative moment when it comes to time. Their publication would have been midway between a birthday and the (then) coming new year. Both are excuses to mark the passage of time. Both feel related to the work being done at NIST in Boulder — the precise hour / minute / second when the calendar flipped from not-my-birthday to my birthday (and from my birthday back to not-my-birthday); the precise hour and minute I was born; the precise moment 2022 faded away and 2023 burst onto the scene.

But that same passage of time can make a person think of the bigger, grander stuff as well. It orients a person, for just a bit, in the universe, and it reminds us of how very small we are. It makes us think about what else is out there, the wonder and beauty and complete chaos that had to be wrangled so that we could simply exist.

I find the juxtaposition so fascinating. The ways in which our lives have come to be so time-dependent and -specific are relatively unremarkable; it’s all we’ve ever known. But to think about the universe separate and apart from the human understanding of time? It’s one of those thoughts that, if dwelled upon for too long or too intently, can hurt your brain. But in the best possible way. It gives us a deeper appreciation of our reality.