LIVE AURORA WEBCAM: Skies above Scandinavia are glowing green in response to today's geomagnetic storm. An aurora webcam at the Abisko National Park in Sweden is broadcasting the light show in real time. Watch it now.
GEOMAGNETIC STORM UNDERWAY: A moderate G2-class geomagnetic storm is underway as a high-speed stream of solar wind swirls around Earth. First contact with the stream produced a magnificant outburst of auroras over Alaska during the early hours of Oct. 25th. Marketa S. Murray sends this picture from Fairbanks AK:
"The storm finally hit," says Murray, "and the auroras were unbelievable."
More auroras are in the offing tonight. The stream has already produced one episode of strong storming that registered G3 on the scale of geomagnetic activity. Around the Arctic Circle, Northern Lights should be quite bright, and lesser displays could cross the Canadian border into the United States. Free: Aurora Alerts.
SINUSOIDAL GROUND CURRENTS IN NORWAY: Not all space weather occurs high overhead. Sometimes it happens in the soil beneath our feet. Example: On Oct. 23rd in the Lofoten Islands of Norway, electrical currents began to flow through the ground, back and forth with a sinusoidal period of 74 seconds. Rob Stammes recorded the phenomenon at his geomagnetic observatory:
"Just after midnight UTC and around 02.36 local time, my ground current instruments picked up these very stable pulsations," says Stammes.
What's happening here? Ground currents are a sign of changing magnetic fields. Earth's magnetic field around the Lofoten Islands was swinging back and forth, inducing a sinusoidal amperage in the soil beneath Stamme's observatory.
These are natural ultra-low frequency oscillations known to researchers as "pulsations continuous" (Pc). The physics is familiar to anyone who has studied bells or resonant cavities. Earth's magnetic field extends out into space and carves out a cavity in the surrounding solar wind. Pressure fluctuations in the solar wind can excite wave modes in the cavity--usually in a noisy cacophany of many frequencies, but sometimes with almost-monochromatic purity. In such cases, Earth's magnetic field "rings like a bell" with slow tones that reach all the way down to the ground. That's what happened on Oct. 23rd. References: #1, #2, #3.
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