Stars twinkle due to the Earth’s atmosphere. As light from a star travels through the vacuum of space and enters our atmosphere, it encounters varying layers of air with different temperatures and densities. These layers cause the light to refract, or bend, in different directions. This refraction varies constantly due to atmospheric turbulence, making the star ’s light appear to flicker or ‘ twinkle ’ when observed from the ground. Stars twinkle , while planets (usually) shine steadily. Why ? Stars twinkle because they’re so far away from Earth that, even through large telescopes, they appear only as pinpoints. What makes stars appear to twinkle in the night sky, as seen from Earth? And why is it that stars twinkle , but planets do not? Learn how light, air, and physics create the twinkle of stars in this fascinating article. Discover the difference between stars and planets, the role of atmospheric turbulence, and the history of star gazing.
