Summer isn't even over in the Northern Hemisphere, but the season of the northern lights is clearly getting an early start.
Saturday's autumnal equinox marks the traditional start of the aurora season in Arctic regions, and with solar activity building up to the top end of its 11-year cycle, we can expect more than the usual allotment of glow-in-the-dark skies. For some reason, this last week of summer has been particularly active on the sun.
"Another day, another coronal hole high-speed stream," the National Oceanic and Atmospheric Administration's Space Weather Prediction Center reports today on its Facebook page. That means there's a higher chance of interaction between the electrically charged particles of the solar wind and our planet's magnetic field. SpaceWeather.com's Tony Phillips quotes NOAA forecasters as saying that there's a 25 to 30 percent chance of strong polar geomagnetic storms over the next three nights.
If the geomagnetic buffeting gets too strong, that's potentially bad news for electric-grid managers and satellite operators. But a mild elevation in solar activity is a boon for aurora-watchers, and it looks as if we're experiencing the bright side of a solar upswing right now.
Chad Blakley, a photographer and tour guide for Lights Over Lapland at Sweden's Abisko National Park, says the sights have been impressive — and he has the pictures to prove it.
"Aurora season has been in high gear for nearly a month in Abisko, and it looks as though this year could be something very, very special," he told me in an email. "We are entering the peak of the solar maximum, and if history is any indicator we should see a marked increase in aurora activity. As you can imagine, I am one very happy man."
Ed Stockard sent in a similarly glowing report from Summit Station, a research facility that's 10,530 feet above sea level on the Greenland ice sheet. "The auroras came on fast and furious, moving and dancing across the entire sky," he told SpaceWeather.com. "Aurora season has definitely begun on top of the ice sheet. Bring on the lights!"
Stockard has already been posting some fantastic pictures to his Flickr gallery. In a follow-up email, Stockard told me more about the Summit Station operation, which is sponsored by the National Science Foundation:
"There are five of us here for what we call the first phase of winter. This lasts between mid-August and early November. At that time, another crew of five takes over until sometime in February. A third phase completes our winter phase until mid-April, when an inflated summer crew comes in. The summer season is busy at Summit with researchers mainly from the U.S. but also around the world, doing their NSF-funded research. Most science involves atmospheric research and is tied to the deep ice core drilled here in the 1990s. ..."
Check out these images from Blakley and Stockard, as well as a time-lapse video captured by Helge Mortensen in Tromsø, Norway. You can expect to see a lot more of this in the months to come.
The northern lights ripple over Summit Station on the Greenland ice sheet.
The auroral display takes on different hues over Sweden's Abisko National Park. The color variations are due to the differences in the composition of the atmosphere at different altitudes. The greenish glow dominates, but the aurora can turn reddish at higher altitudes, as seen here. Check out the Causes of Color website to learn more about auroral colors.
More about the aurora season:
- Your guide to the northern lights
- SpaceWeather.com: Aurora gallery
- Space.com: How the northern lights work
- Cosmic Log archive for auroral glories
Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, sent via email every weekday. You can also check out "The Case for Pluto," my book about the dwarf planet and the search for new worlds.