Mount Etna is a volcano on the island of Sicily, just off the southern tip of the boot of Italy. Etna is the highest active volcano in Europe, and because it's erupted so often over the last few centuries, it's one of the most studied volcanoes in the world.

The most recent series of eruptions of Mount Etna began about a month ago, thrusting the volcano into the news headlines. Satellites captured some of the most spectacular photographs from space that I've ever seen of the smoke plume from an erupting volcano.

This was the view back on July 22. On that day, brisk northwest winds drove Etna's smoke plume out over the Mediterranean Sea. Here's a color view of the same area a few hours later when the trail of smoke was even thicker. The strong northwest winds spread the plume more than 300 miles downwind in a shape that resembles a comet. In recent weeks, the volcano has quieted a bit, but Mount Etna has erupted off and on over the last decade, so we probably have not heard the last from it.