Speed of Light as Mystery

Speed of Light as Mystery

Something strange happens at the speed of light.

The more we think about such questions, the more troubling they become. Paradoxes seem to emerge everywhere if you could travel at the speed of light. Certain ideas had been accepted as true without sufficiently careful thought. Well, Albert Einstein posed a few simple questions that could have been asked centuries earlier. For example, what do we mean when we say that two events are simultaneous?

Imagine that I am riding a bicycle toward you. As I approach an intersection I nearly collide, so it seems to me, with a horse-drawn cart. I swerve and barely avoid being run over.

Now think of the event again, and imagine that the cart and the bicycle are both traveling close to the speed of light. You are standing down the road, the cart is traveling at right angles to your line of sight. You see me, by reflected sunlight, traveling toward you.

Royal Ontario Museum. Most people go about their daily lives as if nothing is happening. Unthinking, uncaring… (quotations from Megan Jorgensen). Source of the image: © Elena

Would not my speed be added to the speed of light, so that my image would get to you constantly before the image of the cart? Should you not see me swerve before you see the cart arrive? Can the cart and I approach the intersection simultaneously from my point of view, but not from yours? Could I experience a near collision with the cart while you perhaps see me swerve around nothing and pedal cheerfully on toward the town of Vincy? These are curious and subtle questions. They challenge the obvious. There is a reason that no one thought of them before Einstein. From such elementary questions, Einstein produced a fundament rethinking of the world, a revolution in physics.