Why do stars scintillate, or twinkle? When we look up into the night sky and see pulsating lights from stars, it's actually a visual distortion. If viewed from high above our atmosphere, starts to not twinkle at all. The twinkle comes from light moving through layers of differeing temperatures and turbulence in the atmosphere. The light that finally reaches our eyes is constantly getting distorted and shifted by moving blobs of air. If you get high enough off the ground, distortion is minimized. That's why most observatories are located on mountaintops, above the layered air of low altitudes.
Greater than usual scintillation is caused by unstable air, increasing humidity, and high winds in the atmosphere, and is a reliable indication of approaching precipitation. In some tropical countries, the increased twinkling of stars high in the sky is considered a sign that the rainy season will soon begin. You can also watch the colors of the stars: high humidity makes stars twinkle blue, further evidence of coming rain.
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