Differences in gas can make light bend, or refract. Think of an object seen through air rising from an asphalt road on a hot day. That warm air slightly warps light, and you see this distortion. Also, rainbows are a result of sunlight refracted in atmospheric water droplets. So, Earth’s atmosphere will bend some colors from especially bright stars more so than others, which makes the source look like it’s flashing colors. — Liz Kruesi, Associate Editor
Earth’s atmosphere is made of layers of gas, and light from distant objects must pass through it to get to our telescopes.