The Last Word On Nothing

(This post is the first in a three-part series. “Talking Universe Blues” will continue over the next two Fridays.)

“Does gravity exist in other universes?”

The question, I admit, stumped me. Did she—fourth row, on the aisle—mean that gravity might be leaking into our universe from a parallel universe? Unlikely. Her puzzled, perhaps lost, expression didn’t suggest that she was coming to the subject bearing an appreciation of brane theory. So, did she want to know whether gravity is universal in the sense that it would, by an extrapolation of the definition of “universal,” apply to other universes? Again, unlikely. Her tone didn’t suggest she was trying to tease out linguistic subtleties. No, something seemed to be missing from the equation—the one that always exists between the Q and the A during a Q&A session. On one side of the equation is the knowledge the questioner wants to acquire. On the other side is the knowledge I can (I hope) provide. In this case, though, something wasn’t adding up.

Think, Richard, think. What does she want to know?

What if what she wanted to know was exactly what she said she wanted to know: whether gravity exists in other universes? I couldn’t answer that question—an inability suggesting that what was missing from the equation was on the answer side, the A side: my side.

It happens. Someone asks a question, and I don’t know the answer. The answer exists; it’s just not in my brain. In which case I simply say, “I don’t know.”

But in this case, what was missing from the equation wasn’t only on the A side. The problem wasn’t that the answer wasn’t in my brain. It was that the answer doesn’t exist. Other universes are a matter of speculation, not knowledge. Yes, something was missing from the equation on the A side, but only because something was missing from the equation on the Q side—her side. I had to ask myself, I realized, not What does she want to know? but the more fundamental What does she know? Or, because I was looking for what was missing on her side of the equation: What does she not know?

Got it.

“Well,” I said, “we don’t even know if there are other universes.”

I’ve been on the road lately, giving readings and talks to help promote my new book, and I’ve found that the Q&A sessions are always an education—not just for the audience (I hope) but for me. These exchanges with the public have gotten me thinking about how to communicate science.

Not that I don’t already think, all the time, about how to communicate science. Usually, though, I think about it in terms of writing. On the page or the screen, the fundamental question is What does the reader know? But trying to reach that reader is, um, problematic. One Amazon reviewer says of my book, “Subject matter was addressed in a manner way over my head.” Another complains of “rather dumbed down science.” In the end, all you can do is hope there are enough Goldilocks readers out there to have made your efforts worthwhile.

In person, though, you can engage in a give-and-take—a Q&A—that can help you gauge an audience member’s level of knowledge. In the case of the woman who asked whether gravity exists in other universes, her follow-up question told me all I needed to know about what she knew—or what she didn’t know.

“How about other galaxies?” she asked.

She didn’t know what she was talking about.

But she wanted to know—and that’s a beautiful thing. What I realized on the road was that people were showing up in large numbers certainly not because of me, and not necessarily because of the book, but because the advance publicity had done its job. It had conveyed to the public the subject of the book: Everything we’ve always thought was the universe—you, me, Earth, planets, Sun, stars, galaxies—is only four percent of what’s out there. The rest is dark: 23 percent dark matter, 73 percent dark energy. As the cashier at one event said as she read the flap copy, “That’s craaaazy.”

Exactly. It’s so crazy that people came to the talks who, I gathered from questions like the ones from Gravity Woman, wouldn’t usually come to a talk on science. (Another Q—different person, same event: Was I suggesting that gravity applies only to our solar system?) Early in the book tour I came to understand that the answer to the question What do they know? was, generally, Very little.

So I learned to start my talks with what I considered the basics of astronomy. I talked about Galileo’s discovery of mountains on the moon, of moons around Jupiter, of hundreds of stars. I talked about the subsequent discoveries, over the following four centuries, of other planets, of other moons around those planets, of other stars. Of planets around those other stars. Of other galaxies. I talked about the motions of galaxies, and about how observations of the motions of galaxies led to the discovery of evidence for dark matter. I talked about the expansion of the universe, and about how observations of the expansion of the universe led to the discovery of evidence for dark energy.

Then I took questions.

And that’s how I learned to ask myself not just What do they want to know? And not just What do they know? But What do they not know?

The morning after the Gravity Woman event, a fellow member of the Last Word on Nothing masthead who had been in the audience e-mailed me to offer her own suggestion as to what had been missing from the Q side of the equation. “High school physics,” she wrote.

By then I’d been on tour for a couple of weeks. I’d given maybe a dozen talks. And I knew better.

High school physics?

If only.

(Next Friday, in “Talking Universe Blues, Part 2”: high school physics.)

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Credits: Christophe Dioux (top); portofembarkation.wordpress.com (bottom)