Just recently I was back out at the Integratron out in Landers. For those of you that don't know the Integratron is a building with a large wooden dome out in the Mojave Desert. For more information you can check out their web page at http://www.integratron.com/. One of the big draws for people visiting the Integratron is the acoustics. They have events there called “sound baths” which use crystal singing bowls to create interesting sound patterns.
But the fact that the structure has a dome also creates what is known as a whispering gallery. The term gets its name from the dome of St. Paul's in London. Visitors discovered that strange whispers could be heard when no one was standing next to you. It was determined that the voices were coming from other visitors on the other side of the dome. And at the Integratron the effect is quite remarkable. You can be standing, or lying down as for the sound bath, and you may actually hear the person on the other side of the dome more easily than someone next to you.
The physicist, Lord Rayliegh, developed a theory where he explained how the sound waves travel around the inside of the circular structure. And the sound isn't just for the opposite side, the sounds can actually be heard all along the perimeter of the structure. Waves of this nature became known as whispering gallery waves. And the theory has been used in different branches of science.
At the small scale, optical whispering gallery waves have been used to detect single viruses. And acoustic waves have been used to detect defects in rounded structures. Then again, rainbows are formed as light travels around in spherical water droplets suspended in the sky. And the light travels around the interior of the droplet by whispering gallery waves. At larger scales, when an earthquake occurs waves are released through the Earth and these waves travel around the world, which is round like two domes and can be detected for hours after the earthquake. And even larger variations have been detected in the surfaces of stars.
In Washington D.C. there is a room in the Capitol that is now know as the National Statuary Hall. This is a circular room that now houses a collection of statues. But back in the first half of the 19th century it was actually where the House of Representatives met. Being a circular room, it too acted as a whispering gallery. There is a story that while a member of Congress, John Quincy Adams used the hall's acoustics to eavesdrop on fellow members of Congress.
So nature is willing to give up its secrets, though sometimes we have to learn to hear them in the whispers around us. We just have to take the time to understand them, and then follow them to all the places that they may lead. But even if you don't have any interest in the mysteries of the Universe, track down a domed building and just have some fun with the acoustics. Just be careful what you say. You never know who's listening on the other side of the room.