Devlin's Angle

May 2004

The best popular science essay ever

I became a "math popularizer" almost by accident. In 1983 I had an idea for an April Fools spoof in a national daily newspaper, where I would write a mathematics story that was so counter-intuitive that everyone would think it was a spoof, but the real spoof would be that the story was in fact true. (The story was based on the fact that an engineering company had manufactured a rotary drill that would drill a square hole. To see the mathematics behind this feat, see http://mathworld.wolfram.com/ ReuleauxTriangle.html.) I wrote it up and sent it in to the science page editor at The Guardian newspaper in my then home country of Britain. A couple of days later the editor telephoned me. He explained to me why my piece would not work in a national newspaper, but went on to say that he liked my writing style, and would be interested in seeing other contributions from me. A few months later an engineer at Cray Research discovered a new record Mersenne prime number, and I wrote a 700 word piece describing the discovery. The editor published it, the reader response was good, and within a short while I found myself a newspaper "math columnist", with a twice monthly column in the science section.

It wasn't long before book publishers started to approach me with requests for popular expositions of mathematics. Quite unplanned, I had a second career. Over the years, I have found myself spending more of my time on what has come to be called "public education", but it remains a very small part of my regular activities. Nevertheless, I have taken it seriously. I read as many popular science books and newspaper and magazine articles about science I can, and I study closely the way the different successful science writers and journalists go about their job.

An essential device in trying to convey mathematics or science to a lay audience is metaphor. The more basic and familiar the metaphor, the greater the audience the writer can reach. To my mind, the queen of the metaphor in science writing is K. C. Cole of the Los Angeles Times. K.C. (as she prefers to be called) has published several collections of her articles from the LA Times in book form, and I recommend them all to anyone who wants to try their hand at science writing for a lay audience.

My all time favorite K.C. Cole piece, which I would claim is the best short newspaper article about science ever, first appeared in her "Mind over Matter" column in the Times on May 11, 2000. (Here on the West Coast we don't use the initials "LA", since the New York Times is referred to by its full name.) Titled "Murmurs", it was republished in K.C.'s book Mind Over Matter: Conversations with the Cosmos, published by Harcourt in 2000 (pp. 15-17). In exactly 700 words (the ideal target length for a newspaper column), using a string of brilliantly conceived everyday metaphors, K.C. succeeds in describing the birth and early development of the universe. Not just describing; she brings it to life. At the same time, she manages to convey the dedication and the excitement of the astrophysics community in their quest to piece together this remarkable story.

With K.C.'s permission, I am reprinting her entire article. There is no special occasion. I just felt this marvellous piece deserved a further spin. I have resisted the temptation to analyze the article paragraph by paragraph, although I have done so for myself and found it well worth the effort. You can dissect it for yourself.

Here then, is what I claim is the best short, lay exposition of science there has ever been.


Murmurs

by K. C. Cole

When the universe speaks, astronomers listen.

When it sings, they swoon.

That's roughly what happened recently when a group of astronomers published the most detailed analysis yet of the cosmos's primordial song: a low hum, deep in its throat, that preceded both atoms and stars.

It is a simple sound, like the mantra "Om." But hidden within its harmonics are details of the universe's shape, composition, and birth. So rich are these details that within hours of the paper's publication, new interpretations of the data has already appeared on the Los Alamos web server for new astrophysical papers.

"It's stirred up a hornet's nest of interest," said UCLA astronomer Ned Wright, who gave a talk to his colleagues on the paper - as did so many others - the very next week.

So what is all the fuss about? Why are astronomers churning out paper after paper on what looks to a layperson like a puzzling set of wiggly peaks - graphic depictions of the sound, based on hours of mathematical analysis?

Because there's scientific gold in them there sinusoidal hills.

The peak and valleys paint a visual picture of the sound the newborn universe made when it was still wet behind the ears, a mere 300,000 years after its birth in a big bang. Nothing existed but pure light, sprinkled with a smattering of subatomic particles.

Nothing happened, either, except that this light and matter fluid, as physicists call it, sloshed in and out of gravity wells, compressing the liquid in some places and spreading it out in others. Like banging on the head of a drum, the compression of the "liquid light" as it fell into gravity wells set up the "sound waves" that cosmologist Charles Lineweaver has called "the oldest music in the universe."

Then, suddenly, the sound fell silent. The universe had gotten cold enough that the particles, in effect, congealed, like salad dressing left in the fridge; the light separated and escaped, like the oil on top.

The rest is the history of the universe: The particles joined each other to form atoms, stars, and everything else, including people.

"The universe was very simple back then," said Caltech's Andrew Lange in one talk. "After that, we have atoms, chemistry, economics. Things go downhill very quickly."

As for the light, or radiation, it still pervades all space. In fact, it's part of the familiar "snow" that sometimes shows up on broadcast TV. But it's more than just noise: When the particles congealed, they left an imprint on the light.

Like children going after cookies, the patterns of sloshing particles left their sticky fingerprints all over the sky.

The pattern of the sloshes tells you all you need to know about the very early universe: its shape, how much was made of matter, how much of something else.

The principal is familiar: Your child's voice sounds like no one else's because that resonant cavities within her throat create a unique voiceprint. The large, heavy wood of the cello creates a mellower sound than the high-strung violin. Just so, the sounds coming from the early universe depend directly on the density of matter, and the shape of the cosmos itself.

Astronomers can't hear the sounds, of course. But they can read them on the walls of the universe like notes on a page. Compressed sounds gets hot and produces hot splotches, like a pressure cooker. Expanded areas cool. Analyze the hot and cold patches and you get a picture of the sound: exactly how much falls on middle C or B-flat.

What they've seen so far is both exciting and troubling. The sound suggests that the universe is a tad too heavy with ordinary matter to agree with standard cosmological theories; it resonates more like an oboe than a flute. Something's going on that can't be explained. The answers will come as even more sensitive cosmic stethoscopes listen in over the next few years.

Lest you think these sounds are music only for astronomers' ears, consider: The same wrinkles in space that created the gravity wells that gave it rise to the sound also blew up to form clusters, galaxies, stars, planets, us.

Even Hare Krishnas murmuring Om.


Devlin's Angle is updated at the beginning of each month.
Mathematician Keith Devlin (Email: devlin@csli.stanford.edu) is the Executive Director of the Center for the Study of Language and Information at Stanford University and "The Math Guy" on NPR's Weekend Edition. For a complete list of Math Guy segments, with links to the audio files on the NPR website, go to http://www.stanford.edu/~kdevlin/MathGuy.html

Devlin's most recent book is Sets, Functions, and Logic: an Introduction to Abstract Mathematics (Third Edition), published by Chapman and Hall in 2003.