Cosmologist Janna Levin on the Musical Nature of the Universe

There's rhyme and repetition in two-minute songs...and in galaxies 300 million light years away. Coincidence?

credit: Maggie Shannon

Here’s a wound from early in my teaching career: After listening to a student’s song in class, I recommended he repeat a phrase. He asked, “Why?” and before I could respond, a disgusted student hissed, “Because we’re not in a music class . . . we’re in a music industry class.” I didn’t sleep that night.

Song sections repeat, but why? When we rhyme, we repeat a sound, but why? Martin Luther King Jr. repeated the phrase, “I have a dream,” but why?

Philosophers and writers—Plato, Kierkegaard, Nietzsche, Vico, Woolf, and McLuhan, to name a few—have agonized over the roots of repetition. They discuss past lives, time spirals, eternal returns, and the possibility that repetition doesn’t even exist. All of which is fascinating, but if I’d answered my student’s question—“Why repeat stuff?”—with, “Well, class, gather ’round. Nietzsche once said . . . ,” they’d have walked out.

I wondered if a universal answer might come from the universe itself. So I asked an expert.

credit: NASA

It’s Space Time

I met Janna Levin at a grand opening party for a mutual friend’s robot factory. She’s a cosmologist, the Claire Tow Professor of Physics and Astronomy at Barnard College of Columbia University, a Guggenheim Fellow, chair and director of sciences at Pioneer Works, and author of Black Hole Blues and Other Songs from Outer Space, which tells the story of the fifty-year search for the sound of colliding black holes as they “slosh in space-time . . . like waves on an ocean.”

Songwriters and astrophysicists have an affinity for repetition. It’s frequently used as a tool in music, but for astronomers, there seems to be an assumption that repetition is indicative of intelligent life—or at least that the possibility can’t be taken off the table.

Absolutely. One of the things SETI—the Search for Extra Terrestrial Intelligence—does is that they look for very regular mathematical signals because they assume that nature won’t provide such a thing—nature’s messy, and so nature can’t do anything so regular. So if you find an incredibly regular signal, you’re hoping that it was sent by somebody who controls their environment, you know, who made it go that way.

What does it say about us that we’re so intrigued by repeated information?

I am a big believer that we inherit mathematical structures because math made us. Evolution is guided by forces of nature— that’s how we evolve—and those forces, not surprisingly, leave an imprint in the structure of our minds. What else is going to be left there, something magic, some magic thing, you know? So what do we have but the forces prescribed in our minds, which are certain structures, how the neurons connect? Of course they have to be mathematical. And in some larger, genetic sense of who our family was, who our parents were—our parents were the laws of physics. And in our minds, it’s encoded there. And we’re discovering the structure of our minds.

There are also communications within the animal kingdom, like birdcalls, that repeat. And the repetition corrects for errors. So, you know, if you didn’t get it the first time, you get it the next time . . .

We want to be unique in language, but we also want to be repetitive enough that you recognize the words. I want to say those words to you over and over and over again, like with children. And then they acquire language. You need the repetition first to understand what the words mean, but then I want to be able to say something unique by assembling those words in a certain way.

That’s a basic theory of songwriting—choruses that repeat and teach themselves
to the listener . . .

Right. LIGO [the Laser Interferometer Gravitational-Wave Observatory that has recorded the sound of black holes colliding] has a real hard time detecting something that only bursts once. It has to repeat for it to be able to pull it out. In fact, one of the things we really hope from LIGO going forward is that it will hear something for long enough that it’ll be able to hear repetitions—that’s exactly what it’s going to want to look for. And those repetitions will allow it to identify something.

The LIGO facility in Livingston, Louisiana (credit: LIGO)

That’s what I’m talking about!

That’s what science is about—reproducibility, experimentation, the fact that somebody else can do it and get the same answer. I was talking to someone from Oxford who said, “Look, this is a real experiment: In your mind, imagine a circle, divide it by the diameter. You have just derived the formula for pi. That is an experiment. And anybody can do the same experiment in their minds and get exactly the same answer.” I consider that to be as tangible as anything. It might not mean that I physically, externally, took out a tape measure, right? But that is as real to me as if I had, and in some sense it’s more real because my tape measure is imperfect, but in my mind, it’s perfect. How is that not real? That’s real.

Terrifying, yet completely reproducible. Like a Rush song.

So, repetition, whether from the same source or the same computation, makes something real.

I think a lot of people who are as inclined as I am toward abstraction struggle with “reality” because it’s less real. “What do you mean that chair was blue? I think it’s persimmon-colored.” “I think it’s lavender.” Like, there’s less reality in reality than there is in our minds. So it’s quite comforting to know that if you’re from Bangladesh, 200 years ago, and you did the same pi thought experiment, it’s 3.14159 et cetera. There’s a sense of connectedness that’s very profound. Very profound. So I think if you think of repetition as an evolutionary trait, then it makes sense that we have it.

*

“If repetition sounds boring to you, just look up at the night sky. See? Not boring!”

I’ll always wish I had a better answer to give my disillusioned student that day, and maybe that’s what regret is—the ache of our internal math not checking out.

And yet, strangely, it’s worked out for both of us: she does, in fact, repeat choruses now, and is finding a lot of success in her career; and that same question—”Why repeat stuff?”—repeats, every semester, like clockwork, or bird calls, seasons, pulsars, the calculations of pi, or yes, the chorus of a song.

An enhanced excerpt from Music, Lyrics, and Life, available in print and audiobook.

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