Storm in a Teacup: The Physics of Everyday Life(49)

And this is what we walk around in every day. Zooming past our heads are overlapping ripples from phones, Wi-Fi networks, radio stations, the Sun, heaters, and remote controls. And those are just the light waves. On top of that is the sound: the deep rumbles of the Earth, jazz music, dog whistles, and the ultrasound being used to clean the instruments in a local dentist’s office. And then the ripples on the cup of tea as we blow on it to cool it, ocean waves, and the undulations of the surface of the Earth itself from the occasional earthquake. And more. We’re filling our world with more waves all the time, as we use them to detect and connect the details of our lives. But they all behave in basically the same way. They all have a wavelength. They can all be reflected and refracted and absorbed. Once you understand the basics of waves, the trick of sending energy and information without sending stuff, you’ve got a huge grasp on one of the major tools of our civilization.

In 2002, I was working in New Zealand at a horse-trekking center near Christchurch. One evening, the phone rang and, to my astonishment, it was for me. The phone had a cordless handset, so I could take it outside and sit on the hillside, looking out through the dusk over the New Zealand countryside. It was Nana. She had decided to call me (I’d been away from the UK for about six months by that time, and I hadn’t spoken to my family at all), and so she pressed the right numbers on her phone and there I was, on the other end. As her familiar Lancashire accent asked about the food and the horses and the work, I was completely distracted by the weirdness of the situation. I was on the other side of a gigantic planet, as far from my family as it was possible to be while still on Earth (7,918 miles in a straight line, and 12,400 miles as a very enthusiastic crow flies), and here was Nana on the phone. Just . . . talking. Chatting. But there was a whole planet in the way. I’ve never quite got over how disconcerting those ten minutes were. These days, our planet is connected by waves. We all talk to each other, all the time, via waves that we can’t see. It’s such a gigantic achievement, and so fundamentally odd. The work of inventors like Marconi and events like the sinking of the Titanic pointed the way toward the world of today where we take these connections for granted. I feel very grateful that I was born just early enough to experience the astonishment that this particular achievement deserves. Our eyes can’t detect these waves, and it’s always hard to appreciate the invisible. But next time you make a phone call, give it a thought. A wave is really a very simple thing. But if you’re clever about how you use it, it can shrink the world.



* One of the unintentional discoveries from my time at sea is that the best way to provoke a bird enthusiast is to casually ask about seagulls. There are gulls (lots of different types), and some of them live in or on or near the sea. But there is no such thing as a seagull. Bird enthusiasts will either spend hours explaining this to you or leave in a huff.

? If you get the chance to see them from the side, you’ll see that they’re actually going around in small circles. The point is that they’re not traveling with the wave.

? Other Pacific Islanders, most notably the Tahitians, also had surfboards. However, it seems that they only lay or sat on them. The Hawaiians pioneered the idea of standing up on the board, and so “surfing” as we understand it today.

§ Experiments showing that light behaves like a wave were relatively straightforward. It took an extremely clever experiment the size of the Earth’s orbit around the sun to reveal the most counterintuitive thing about light: There isn’t any “stuff” that’s doing the waving. Instead, the waves travel as disturbances in electric and magnetic fields. The test became known as the Michelson–Morley experiment, and it’s one of my favorites of all time, because it’s simple to understand, it’s extremely elegant, and it used our whole planet as a vehicle to test their hypothesis.

? Like many materials, diamond slows down different colors of light—different wavelengths—by different amounts. So part of the sparkle comes from the diamond separating out the colors, as well as bouncing them back at you.

# It would be interesting to see the color chosen by children to draw water in a culture that doesn’t have this habit. I think that we identify water as blue because we know about the oceans, and we have aerial photography and very clean swimming pools. But few cultures had those things until recently. Are there enough hints that they would unconsciously color it blue? Or is that entirely a learned habit?

** Although astronomers haven’t always believed that it’s the majesty of the cosmos they’re looking at. In 1964, Robert Wilson and Arno Penzias detected waves from the sky at microwave wavelengths that shouldn’t have been there. They spent a long time trying to work out which bit of the sky or their telescope was messing up the measurement, sure that something was generating extra microwave light. They also cleared out some nesting pigeons from the telescope, along with their droppings (euphemistically described as “white dielectric material” in the paper they wrote). The unwanted background light persisted. It eventually turned out to be the signature of the Big Bang, some of the most ancient light in the universe. There is something special about an experiment that has to be very careful to distinguish between the aftereffects of pigeon poop and the aftereffects of the formation of the universe.

?? Which has very little to do with how a real greenhouse does anything.

?? That’s why mobile phones are called cell phones in US English—the network is cellular.