What causes atmospheric twinkling?

Atmospheric twinkling happens when light from stars or other faraway objects bends and wobbles as it travels through Earth's air.

Imagine you're looking at a candle flame on a windy day. The flame flickers because the warm air around it moves in different directions, making the light look like it’s dancing. Something similar happens with stars, but much farther away!

Air is not always still, and it’s made of tiny layers that can be warmer or cooler than others. When light from a star passes through these layers, it bends a little bit each time it hits one. This bending makes the star appear to shift position very slightly.

Now think about playing with water in a kitchen sink. When you look at something under the water, like a spoon, it looks bent, that’s because light changes direction as it moves from air to water. The same idea applies here: light is bending as it goes through different parts of Earth's atmosphere, making stars seem like they're twinkling.

Sometimes this makes the star look brighter or dimmer too, just like how a flame can flicker, but with stars, you’re seeing something that’s very far away, and it feels like it's having a little party in the sky!