Did you know a rainbow is a full circle? A rainbow is formed when sunlight is refracted (bent), reflected inside raindrops, and then refracted again as it exits. This process sends light out at a specific angle — about 42° from the direction opposite the sun — forming a cone of light. If you trace all those angles around your shadow, they form a complete circle. From the ground, the horizon cuts off the bottom half of the circle, so we usually see just a semicircular arc. You can see the entire