SOLAR WIND APPROACHES EARTH: NOAA forecasters say that a stream of solar wind could hit Earth's magnetic field during the late hours of April 19th. We think April 20th is more likely. Either way, polar magnetic unrest is possible in the next 24-48 hours. High-latitude sky watchers should be alert for auroras. Free: Aurora Alerts
AURORA SEASON IS NOT FINISHED: As northern spring unfolds, the Midnight Sun is coming to the Arctic Circle. Nevertheless, auroras are still visible. Sacha Layos photographed this display over Fairbanks, Alaska, on April 18th:
"I didn't expect much last night, so I went to sleep like a normal person," says Layos, who spends most winter nights under the stars of Alaska photographing auroras. "I happily woke up from a dream to this sky around 2:30 a.m.!"What happened? A crack opened in Earth's magnetic field--something that happens often during weeks around equinoxes. Ambient solar wind poured in to fuel the unexpected display.
The green in her photos shows that northern aurora season is not yet over. However, the blue in her photos shows that the end is near. Enjoy it while you can.