The southern counterpart to the northern lights – as seen from above by astronauts on the International Space Station.
Charged particles from the Sun stream along the Earth’s magnetic field, guided to the north and south poles, where they crash into our atmosphere and generate light. The color of the light depends on the molecule or atom hit; in this case, the green glow is due to oxygen.
Although the particles generating the light tend to be 80 – 160 km up (50 – 100 miles), the space station is even higher. This view is also well off to the side; the astronaut who took the picture was looking at the limb of the Earth, several thousand miles away. All in all the color, perspective, and the amazing glowing stream combine to make this a lovely and decidedly unearthly photograph from space.
Image credit: NASA/Expedition 23