New Aurora Pictures: Deep-Sky Lights Revealed

Auroral Curtains

Photograph by Wayne Barsky

Ghostly green curtains of light hang over the frozen Koyokuk River in Alaska in a picture taken April 2.

Photographer Wayne Barsky drove more than 300 miles (483 kilometers) north of Fairbanks to witness auroras for the first time. Although Barsky saw just a pale green glow with the naked eye, his long-exposure shot brought out fainter blue tones higher in the atmosphere.

Two days before the sky show, a gust of solar wind had blasted off from the sun. The cloud of charged particles collided with Earth's magnetic field, and particles flowing along the field lines toward the Poles interacted with Earth's atmosphere.

Excited atoms in the atmosphere released the added energy as light, creating the streamers of faint auroras seen April 2 and 3 throughout Canada and parts of the northern United States. (Related pictures: "Solar Storms Light Up Arctic Night.")

Published April 8, 2011

Aurora's Magenta Majesty

Photograph by Zoltan Kenwell

The aurora borealis—or northern lights—appears as ribbons of purple and pink in a picture taken just north of Edmonton, Canada, on the night of April 2.

When the sun's charged particles reach the atmosphere below about 60 miles (96.5 kilometers) from Earth's surface, they mainly hit nitrogen molecules, which glow in rosy shades. More common green auroras are created by oxygen atoms between 60 and 120 miles (96.5 and 123 kilometers) above the ground.

No matter the colors, "everyone should see the Aurora Borealis at least once with their own eyes to really appreciate its splendor," photographer Zoltan Kenwell said in an email to National Geographic News.

Published April 8, 2011

Doused in Green

Photograph by Wayne Barsky

Brilliant auroras dance over snow-capped mountains near the Koyokuk River in Alaska, north of the Arctic Circle, in a long-exposure picture taken April 2

"It was an extremely dark and moonless night, and the frozen river and mountains were illuminated only by the aurora[s], which painted them a pale green," photographer Barsky said.

For high-latitude observers, auroras like this one are fairly common, occurring as many as two or three times a week during the spring and fall. (Also see "Giant 'Space Tornadoes' Spark Auroras on Earth.")

Published April 8, 2011

Ghostly Pillars

Photograph by Zoltan Kenwell

Faint pillars of auroral light spread across the sky above northern Alberta, Canada, in a 15-second-exposure picture taken in the predawn hours of April 2.

Auroras are more common in the Northern Hemisphere during spring and autumn. One theory for why this happens has to do with the fact that the magnetic fields of Earth and the sun are constantly pushing against each other.

If the sun's field tilts in just the right way, it can partially cancel out Earth's magnetic field at the point of contact, effectively ripping holes in Earth's protective "force field." (See "Magnetic-Shield Cracks Found; Big Solar Storms Expected.")

The resulting increase in solar particles reaching the atmosphere feeds auroral sky shows—but can also damage satellites in orbit and electrical grids on the ground.

Published April 8, 2011