Stars twinkle, planets don't

⏱ 4 min read

That dazzling “star” that refuses to twinkle? It’s probably a planet.

Stars are so far away they arrive as pure points of light, so our turbulent atmosphere makes them flicker and twinkle. Planets are much closer and show a tiny disk — big enough that the flickering averages out, so they glow with a steady light.

A star arrives as a single point, so our atmosphere makes it twinkle. A planet shows a tiny disk that averages out the flicker — steady light.

Just after sunset you spot a bright point of light that shines steadily, without twinkling, near where the Sun went down. Best guess?

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