Just like magic, big “islands” appear to come and go on the lakes and seas of Titan, the largest moon of Saturn. They first showed up in radar images snapped 10 years ago by the Cassini spacecraft. And planetary scientists have been trying to explain them ever since.

Titan is bigger than the planet Mercury. It has a cold, thick atmosphere. Hydrocarbons at the top of the atmosphere create an orange haze — like the smog that blankets many cities. Methane and ethane form clouds. They also fill the lakes and seas.

In most of Cassini’s images, these bodies of liquid looked dark and calm — any waves would be no more than a fraction of an inch high. But occasionally, a bright patch would appear — like an island suddenly rising from the depths.

There are several possible explanations: big waves, patches of nitrogen bubbles, and others. And a study this year suggested sheets of ice. In this scenario, particles would drop from the haze layer, forming ice grains along the way. The grains could collect in sheets along the shore. The ice would be porous, like a sponge or a honeycomb. A sheet might break away and float into a lake or sea. Eventually, though, the spaces would fill up, the ice would sink, and the island would vanish — just like magic.

Look for Saturn near our own moon the next few mornings. It’ll stand well to the left of the Moon at dawn tomorrow, but much closer to the Moon on Thursday.

Script by Damond Benningfield