why

Exploring Everyday Wonders: Light, Sky, Moon, Rainbows, and Rain

Why the sky looks blue (and a note about the Moon): The Sun emits white light, which contains all colors. As this light passes through Earth's atmosphere, shorter blue wavelengths scatter more than the others, making the sky appear blue to our eyes. In contrast, the Moon has no atmosphere, so its sky stays dark even during daytime.
How rainbows form and a simple near-home experiment: When sunlight enters raindrops, it bends (refracts) and splits into the spectrum of seven colors. Because dispersion happens in a consistent way, rainbows appear in the same color order every time. You can try a mini rainbow by spraying water with the Sun behind you.
Why the Moon seems to follow you and how rain happens: The Moon looks like it chases you simply because it is very far away—about 384,000 kilometers from Earth—so its motion is barely noticeable compared with nearby objects. Rain arises from the water cycle: the Sun heats water from oceans, lakes, and rivers into vapor, which rises and condenses into clouds; when clouds get heavy, rain falls, replenishing water for plants, animals, and people.