As the Earth rotates in its orbit around the Sun, the path of sunlight moves from east to west across the globe. As we know, when it’s light on one side of the world, it’s dark on the other. To demonstrate this, I filmed the sky at dusk from three locations on the same line of latitude. The three cameras reveal what we normally cannot see: the camera on the right (east) is the first to darken. I calculated that the cameras should be placed 50 miles apart to achieve a practical and discernible difference, this equates to a total distance of 100 miles.