Milky Way and the Northern Lights

The Milky Way appears from behind the colourful curtains of the Northern Lights.

This was the scene last Saturday night, into the pre-dawn hours of Sunday morning, May 5, as the summer Milky Way rose in the east while a display of aurora played across the northern sky. The Northern Lights weren’t particularly bright this night, but the long 2-minute exposure I used to bring out the Milly Way recorded the aurora with colours and an intensity only the camera could see this night.

The green is from oxygen glowing in the lower part of the atmosphere, though still some 80 km up, where only rockets and high-altitude balloons can fly. The tops of the auroral curtains are tinged with the pinks from another type of oxygen emission possible only at the very top of our atmosphere, where molecules are few and far between and what’s left of the air that surrounds us meets the vacuum of space some 150 km up.

From Earth it’s hard to visualize just what we are seeing when we look at display like this. But check out some of the Aurora videos at NASA’s Gateway to Astronaut Photography of Earth. You’ll see time-lapse videos taken from the Space Station as it flies by and through the same types of aurorae with green lower bands and pink upper fringes, beautifully captured floating high above the Earth in vertical curtains reaching up into the blackness of space.