It’s hard to look away from a stunning sunset. If you turn around, though, you might see another colorful show, although one that’s more subdued than the main event.

As the Sun drops below the western horizon, Earth’s shadow climbs into view above the opposite horizon. It forms a dark blue band that climbs higher as the evening progresses. It’s also visible in the dawn sky, shortly before sunrise. The band forms a thin wedge where it intersects the horizon, and grows thicker as it approaches the point directly opposite the Sun.

At the same time, a band of bright pink appears above the shadow. It’s known as the anti-twilight arch. It’s created when the red hues of sunlight strike particles in the atmosphere on the opposite horizon, causing them to shine reddish pink. It’s also known as the Belt of Venus. And right now, Venus – the “evening star” – is directly opposite that band in early evening.

As the fuzzy line that separates the two bands climbs higher, it gets even fuzzier. Soon, it reaches a height where the atmosphere is thinner, so less red light is scattered there. The pink belt fades to blue, and both the Belt of Venus and Earth’s shadow merge into the darkening night.

Earth’s shadow extends far into space. When the geometry is just right, the Moon passes through the shadow, creating another beautiful show: a lunar eclipse. And an eclipse is coming up tomorrow night. We’ll talk about that on our next episode.

Script by Damond Benningfield