Belt of Venus

What is this naturally occurring atmospheric phenomenon that makes the sky blush?

We are used to seeing glorious sunsets and sunrises, but on the opposite horizon to the Sun a little-known atmospheric phenomenon called the Belt of Venus – named after the Roman goddess of love – can be witnessed, offering equally stunning views.

Belt of VenusAs the Sun sets or rises its light moves through the atmosphere and casts a shadow of the Earth onto the sky. For a setting Sun, as the light moves downwards, this shadow appears to get closer and closer to the horizon until the Sun disappears from view completely and the sky is left black. For a rising Sun, however, the opposite is true until the shadow dissipates and the sky appears entirely blue.

The dark band of the Earth’s shadow at dusk and dawn often has a light pink arch above it, known as the Belt of Venus. It extends about 10-20 degrees up from the horizon, acting as a boundary between the shadow and the sky. The effect is due to the reddened sunlight being backscattered in the atmosphere, which produces the rosy glow.