Biomythography - Note 30
Infinite Light in a Box
"You can't do it," Richard said.
"Well, I want to try." I put my hands on my hips and wished I'd brought my light box. Then I could show it to Richard and maybe he'd understand. I'd made a drawing for him with a good pencil on his elementary school lined paper. I'd tried to show him the angles of the light rays.
"It's impossible." He leaned closer for emphasis.
"Light is particles. It bounces. And it bounces off mirrors." My drawings weren't finished but I was sure about the concept. Since light bounced between mirrors, I could shut the door of the box at any time and capture the light that was inside. The photons would keep bouncing around off mirrors until I opened the box.
Something was wrong with my box, though. It never seemed to capture light in a way I could detect. The problem might have been in my detection method. (It was: open the box in the dark.) The issue might have been in the tape and mirrors. My mother wouldn't let her eight-year-old son cut up her mirrors to fit exactly into the box. There were gaps between the reflective surfaces.
Actually, I wasn't sure how to cut a mirror. One of the neighbors was a rock collector. He had a diamond saw. I wanted to try that. My next idea was to break a bunch of mirrors and tape the shards together.
"Mom!" Richard called. "Tell him it's impossible."
That was unfair. Calling a parent into the debate was like bringing in a tank against the infantry. But I was ready with my description and my drawings. I was sure my ideas matched with what I had read in physics articles. Richard's mother, Mary, kept saying something had to be wrong. To her irritation, I kept insisting the principles were fine.
"It won't work," Mary said. "I can't explain it in terms of photons but I'm not going to argue about it anymore. I know someone who can. John!"
She called her husband over. Now it was Richard and two adults against me. But I was sure I was right. I had been reading about photons all year. John, a tall and normally quiet man, ambled over.
"Tell him that this is impossible," said Mary. Richard added extra 'impossibles' for emphasis.
"Well, let me hear him say what he's trying to do, first."
For the third time, I tried to draw it. I described the light box and the basic idea of photons bouncing endlessly off mirrors until I released them.
"There are a few things wrong with the experiment," he said. Maybe he suppressed a chuckle. It was only for a second and, if that's even what it was, he kept it muted. Rather than growing scornful, his voice grew extra careful and gentle. "For one, did you know that mirrors aren't perfect?"
My eyes widened. Whatever he was getting at, I knew it had never occurred to me. Mirrors reflected light. I knew they did.
"Lightwaves aren’t particles or at least they're not just particles. But never mind that. You do understand a lot of what you've read. The problem is that, even if photons were exactly how you think, your box would fail because the mirrors can only reflect a percentage of the particles each time. I don't remember what percentage it is for standard, consumer-grade mirrors but it doesn't matter. Even if you capture eighty percent of the photons each time, that still means you're losing twenty percent. And the light bounces so fast. You're losing all of the light in less than a second. In less than a tiny fraction of a second, even.”
"It's impossible, right?" Mary said. Richard nodded. "Just tell him that it's impossible."
"Well, hate to say that because there are a few labs trying to do this sort of light capture right now." He couldn't keep from showing a twinkle in his eyes. "They have better equipment than cardboard and mirrors. Even the best scientists couldn't do it with that. So with the tools you've got, I'm sorry, it isn’t feasible."
I felt slightly crushed but not as much as I might have been. Mostly, I felt confused by the word ‘feasible.’
"But this is a really good experiment to try," he continued. He spoke as if he wanted to get that part in quickly before I lost heart. "There is a team at University of Maryland using specially focused lenses to coax light into a circle. They've got that part done. What they really want to do is something you mentioned, too, and that's to isolate a single photon. They haven't achieved that yet but they think they're close.”
He went on to say that it was a very interesting problem to a lot of physicists.
“How do you capture light?" He rolled his shoulders, less than a shrug but definitely a gesture of uncertainty. "It’s difficult.”
John Price, as usual, seemed a bit like someone else had dressed him but he didn't mind. He was always well put together and yet seemingly indifferent to his clothes. This time, he'd worn a plaid shirt that didn't look like something he would pick for himself. It was too busy and too bright. The sleeves were short, though. The fabric was light and he looked comfortable on the warm day as he explained photons for a few minutes more.
He talked about light being a wave and a particle both. I wasn't happy with his ideas. How could light be more than one thing? That didn't match with the binary logic my father was teaching me. And what did it mean for a fundamental particle to be a wave? At no time in the discussion, though, did he make fun of my cardboard box with mirrors taped inside.
John said there was nothing wrong with my detection method of opening the box in the dark.
"If a box like that could work, you'd see a flash of light." He half-shrugged again. "Or maybe it would happen too fast and it would be hard to see but that part is really not bad design."
The most critical thing he reiterated was that I was trying to solve a multi-million dollar problem. Other good experiments might be done with my limited materials. If I thought of those, I should do them.
“Anyway, aren’t you worried that breaking mirrors could cause bad luck?” His voice took on a teasing tone but still with gentleness.
“No.” That sounded like something one of my uncles would say. But I hadn’t thought of it.
“Oh, that’s good.” He nodded to himself.