• Did you know rainbows can theoretically exist on other planets? Rainbow-like optical effects can occur in other worlds, though they require specific liquids or vapors rather than Earth’s water. Known as the glory effect, there is some evidence for them on Venus and even on exoplanets.
• Rainbows (see picture below) tell us about light, water, and our position. They show that sunlight is made of many colors and that light bends and reflects in raindrops. Multiple reflections yield secondary rainbows.
• Because rainbows are an optical illusion, no two people see the exact same view.
• To see a rainbow, stand with your back to the sun and face falling rain or mist to spot the arc. Red light bends at a 42-degree angle. Other colors bend at different angles.
• Droplets must be larger than 1 mm, which means they are falling. The concentration is not high enough to blur the light, so it is much lower than in equilibrium clouds.
• With climate change, the planet will average 4 to 5 more days with rainbows per year due to warmer air holding more moisture and changing cloud patterns. About 66% to 79% of land areas will gain rainbow days, while 21% to 34% of land areas will lose them.

The electrification of modern large industrial heaters now offers an unparalleled opportunity to arrest climate change and improve energy efficiency.