New Aurora Pictures: "Severe" Sun Storm Brightens Skies

Aurora in the Red

Photograph courtesy NASA

Many auroras appear green, but sometimes other colors such as red show up—as in this picture taken from the International Space Station on September 26.

An aurora's colors depend on which types of atoms cause the splash of light. In most cases, auroral lights appear when charged particles from the solar wind collide with oxygen atoms in Earth's atmosphere, according to a NASA statement.

"This produces a green photon, so most auroras appear green. However, lower-energy oxygen collisions—as well as collisions with nitrogen atoms—can produce red photons, so sometimes auroras also show a red band, as seen here."

(See more aurora pictures.)

Published September 30, 2011

Arc Over the Arctic

Photograph by Darren Horn, My Shot

The northern lights reflect brightly in a lake just outside Yellowknife in Canada's Northwest Territories in a picture taken September 28.

Strong solar storms—such as the September 26 CME that triggered this week's auroras—can also hit low-Earth orbiting satellites with potentially damaging solar particles and magnetic fields, according to NASA. (See pictures of solar eruptions.)

In fact, a recent modeling study found that a solar megastorm would cause satellites to malfunction much faster than previously thought.

Published September 30, 2011

Purple Haze

Photograph by Mika Puurula

Purple and green rays of light streak across the night sky in Sotkamo, Finland, on September 26.

"The moon was at its minimum, and the sky was bright," photographer Mika Puurula wrote on SpaceWeather.com. "There was a powerful aurora show that last[ed] about an hour."

(See "Solar Flare Sparks Biggest Eruption Ever Seen on Sun.")

Published September 30, 2011

English Lights

Photograph courtesy Reed Ingram Weir

Purple and green auroras also painted the sky above Northumberland, England, on September 26.

"We got very lucky with the gaps in the cloud," photographer Reed Ingram Weir wrote on SpaceWeather.com.

(See more pictures: "Huge Solar Storm Triggers Unusual Auroras" [2010].)

Published September 30, 2011

Front-Row Seat

Photograph courtesy Shawn Malone, LakeSuperiorPhoto.com

A brilliant aurora triumphs over the fog on Lake Superior near Marquette, Michigan, on September 26.

"With the solar max coming, hopefully lower latitudes will see what Norway/Alaska get to see on a more regular basis," photographer Shawn Malone told National Geographic News in an email.

(Related: "As Sun Storms Ramp Up, Electric Grid Braces for Impact.")

Published September 30, 2011

Rainbow Auroras

Photograph by Thilo Bubek

A vibrant spectrum of color fills the sky above Tromsø, Norway, on September 26.

"We were lucky that we were able to find a place with clear sky around," photographer Thilo Bubek told National Geographic News. "First we saw some green auroras, but later we saw colors we had not seen this strong [in] the last years."

(Also see pictures: "Multicolored Auroras Sparked by Double Sun Blast.")

Published September 30, 2011

Plain as Day

Photograph courtesy Fabiano Belisario Diniz

The source of the major solar storm was sunspot AR1302, which stretches about 93,000 miles (150,000 kilometers) from end to end and is visible to the naked eye, according to SpaceWeather.com.

Photographer Fabiano Belisário Diniz caught the monster sunspot in a picture he took of the sun setting over Curitiba, Brazil, on September 26.

"It was overcast and cold all day long, but at the end of the day a break in the clouds revealed the sun and AR1302," Diniz told SpaceWeather.com. "What a great sight!"

For more on solar flares, sunspots, and solar wind, read "The Sun-Living With a Stormy Star," in National Geographic magazine >>

Published September 30, 2011