Why do stars twinkle?
How Earth’s atmosphere turns starlight on and off
On a clear and cloudless night away from light pollution, you can see around 6,000 twinkling stars in the sky. The reason they twinkle is thanks to Earth’s atmosphere acting like a humongous house of mirrors, scattering the light before it reaches the surface. Looking through telescopes on Earth, stars appear as tiny pinpoints of light that appear to flicker on and off. This is because a single beam of light entering the atmosphere is refracted across many different layers.