Category Archives: class

Faster than you can say, “3.0 times ten to the eighth meters per second”



photo from here

When I was young, I read a biography of Einstein’s life. (If he wasn’t so brilliant, we might know him as Honest Al). In this book, a story was told about young Albert at the ship docks. A worker had Al stand 50 yards away from him and swung a hammer at an anvil. Einstein learned from this experience an awesome wonder for the speed of sound and light. The rest is history.

What really interests me about the speed of light is how it allows us to peek into the past. When we look out into space, we are not seeing what is, but what was. Here is an experiment I would like to see done – Blake and Chris are standing 3.1 miles away, the point where the earth’s surface curves out of sight, and Blake lights a fire. Let’s say Chris is standing on a cell tower. As soon as Blake lights the fire, he says into his cell phone, “Chris, it’s lit.” Does Chris hear the cell phone first or see the fire first? If he does see the light first, how far away would he have to get in order to hear Blake first?