The moon is often thought of as a lifeless and inactive place. But a new study reminds us that our pale celestial guardian is more dynamic than it seems from afar. Fresh measurements of its flimsy atmosphere back up the idea that our lunar companion is surrounded by an electric shell, and that shell seems to gather power when Earth shields it from the fury of the sun during a full moon.

In effect, when you gaze at a bright full moon shining in the sky, you are probably seeing the lunar orb at its most electric.

Worlds with atmospheres tend to have outer layers known as ionospheres. Material that reaches these extraordinary heights bumps up against the vacuum of