A spectacle of cosmic dust from Paranal

This Picture of the Week takes you all the way to ESO’s Paranal Observatory in the Chilean Atacama Desert, to enjoy a spectacular sunset next to the Very Large Telescope (VLT). But that’s not the only wonder displayed by the clear skies of the Atacama. See that blueish glow across the sky?

The zodiacal light — also called “false dawn” when seen before sunrise — is a faint, diffuse band of light in the night sky, reaching up from the horizon. It follows the direction of the ecliptic — the plane of Earth's orbit around the Sun. This plane is rich in tiny particles of dust, which scatter sunlight and create this phenomenon. The other planets in the Solar System orbit the Sun in roughly the same plane, and therefore can be often seen within the zodiacal light. In this particular image, Venus is the brightest source and Mars is the faint, reddish dot to the upper-right of Venus.

If you’ve never seen zodiacal light before, you’re not alone: the glow is so faint that light pollution or even moonlight can outshine it. Luckily, the Atacama Desert still preserves the full glory of its night skies, a heritage to be protected. How appropriate also that the VLT Unit Telescope enjoying this spectacle of sunlight in the image is the one nicknamed Antu, which, in the Mapudungun language of central-southern Chile, means “The Sun”.