Cosmic Wings

Like giant ghostly wings, green auroras fly across the sky in this mountain scene taken near Anchorage, Alaska, on October 10.

These brilliant auroras were triggered by a coronal mass ejection that hit our planet early Thursday morning. A coronal mass ejection is a cloud of superheated gas and charged particles hurled off the sun.

When such an ejection hits the Earth, the solar particles can interact with charged particles caught in our planet's magnetic field to produce the northern and southern lights.