Dark and Quiet Skies: are we still able to observe planetary alignments?

Photo credit: @Jeff Warner, US CO, CatchingTime.com

On the morning of 18 April 2026, four planets aligned in the sky: Mercury, Mars, Saturn and Neptune. This kind of event, known as a planetary parade, was partly visible to the naked eye, though catching Neptune required a small telescope.

Yet even when the planets line up, the view is no longer guaranteed.

Dark and quiet skies, free from light pollution and human interference, are an essential condition for observing the night sky. Those conditions are deteriorating, for three main reasons:

• Excessive artificial lighting that washes out the stars.

• The rapidly growing number of satellites visible in orbit around the Earth.

• Radio interference that disrupts astronomical observation and affects even the most sensitive instruments.

A planetary alignment can happen exactly as predicted, and still go unseen if the sky above us is too bright, too crowded, or too noisy to look through.

Preserving dark and quiet skies is not only an astronomical concern. It is about keeping direct access to the sky, to knowledge, and to a heritage shared by everyone. The night sky has guided navigation, timekeeping and culture for as long as humans have looked up; losing sight of it is a loss that reaches well beyond astronomy.

At Cosmos for Humanity, we advocate for a sustainable space environment: one that does not take away our view of the sky, but protects it. A responsible approach to orbit means weighing what we place above us against what we stand to lose below.

The alignment of 18 April came and went. The real question is whether we are still giving ourselves the means to see the next one.