What are bright circles?

Bright circles are big, glowing spots you can see when light shines through something round, like a glass or a bubble.

Imagine you're holding up a clear cup to the sun. On the floor or wall behind you, you might see a bright circle, it looks like a sunny spot that’s bigger than the cup itself. That's because the light is passing through the round shape of the cup and spreading out on the other side.

Think about how water flows from a hose. When the hose is straight, the water goes in one direction. But if you bend the hose or put your thumb over part of it, the water spreads out more, it covers a bigger area.

The same thing happens with light. A round object like a glass or a bubble lets light pass through and spread out into a bright circle, just like water from a bent hose.

So next time you see a sunny spot on the floor that looks round, it might be a bright circle, made by light passing through something round!