Space & Atmosphere
Why Do Stars Twinkle?
Stars do not actually flicker. Earth's atmosphere bends their light in constantly shifting ways, creating the twinkling effect. Planets do not twinkle for a specific reason.
Space & Atmosphere
Why Are Sunsets Red?
Sunsets are red because sunlight travels through far more atmosphere at a low angle, scattering away blue light and leaving only red and orange to reach your eyes.
Space & Cosmology
Why Is Space Black?
If the universe is full of stars, the sky should be blindingly bright. The reason it is dark has to do with the age and expansion of the universe itself.
Optics & Atmosphere
Why Do Rainbows Curve?
Rainbows are circles. You see an arc because the ground gets in the way. The curve comes from the precise angle at which each raindrop returns light toward your eyes.
Nature & Physics
Why Is Snow White?
Snow is white because millions of tiny ice crystals scatter all wavelengths of light equally in every direction. Your eyes receive the full spectrum at once, which looks white.
Space & Astronomy
Why Can We See the Moon During the Day?
The moon is visible during the day because it reflects enough sunlight to stand out against the blue sky, depending on its phase and position.
Light & Atmosphere
Why Is the Sky Blue?
The sky is blue because blue light scatters off air molecules more strongly than red light, filling the daytime sky with scattered blue wavelengths.