QR5.2.1 Our Reality Bubble

Figure 5.1. How fast is the earth moving?

Maxwell’s equations describe light as a wave so in the nineteenth century a superfine ether was assumed to propagate it in space. If the earth orbits the sun to give the seasons and spins to give night and day, the ether wind can’t always be stationary (Figure 5.1), so the speed of light should vary: light going against the wind should go slower and light going with the wind should go faster. Then in 1887, Michelson and Morley found to everyone’s surprise that the speed of light was the same in every direction. There was no ether wind! This was deeply counter intuitive – why didn’t the earth’s movement affect the movement of light?

Later, in 1904, Lorentz showed that the equations of light stayed the same if space and time changed as objects moved and in 1905 Poincare deduced the relativity principle, that the laws of physics were the same in every reference frame, so a ball thrown up in a moving car behaves the same as in a stationary car. In our world, constant speed observers see the same laws of physics, so throwing a ball, swinging a pendulum or shining a flashlight is the same on a satellite orbiting the earth at thousands of miles per hour as it is on earth.

This is fortunate because the earth is a planetary platform carrying us through the cosmos. Its spin whirls us around at about 1000mph, it goes around the sun at about 66,000mph and around the galaxy at an amazing 483,000mph. Some estimate our speed relative to the cosmic background radiation at about 1,300,000mph yet science still works on earth as it does in the rest of the universe. How is our reality bubble maintained despite the fact that we live on a moving planet?