Why are rainbows circular when viewed from an aeroplane? © Getty Images

Why are rainbows circular when viewed from an aeroplane?

While we enjoy a semi-circular view of rainbows on land, why can this come full circle when we take to the air?

Asked by: Beat Furrer, Switzerland

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Rainbows are formed when light emerges from water droplets that are in just the right place for the rays to enter our eyes. Such droplets always lie on a circle facing the Sun. Unless we’re airborne we can only see a ‘bow’, as the ground blocks out the rest.


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