www.spaceweather.com
A QUAKE IN EARTH'S MAGNETIC FIELD: When a CME from the sun struck Earth on April 22nd, our planet's magnetic field reverberated from the impact. A day later, a stream of solar wind arrived, hit, and had the same effect. In Lancashire, England, a magnetometer operated by Stuart Green captured the quaking of Earth's magnetic field:
"The data clearly show when the relative calm was shattered on April 21st at around 16:30 (UT) when the CME struck, being quickly followed by fast flowing solar wind from a large and persistent coronal hole," says Green. "The rumblings have been continuing through the intervening days."
Vibrations in the magnetic field allow particles normally trapped in our planet's magnetosphere to rain down around the poles, igniting auroras. Thomas J. Spence was camping in the Boundary Waters Canoe Area of northern Minnesota on April 22nd when the sky suddenly lit up:
"I ventured into the BWCA less than 24 hours after the ice was gone from Kawihiwi Lake--and coincidentally not long after the CME impact," says Spence. "The aurora began soon after sunset and continued until first light. It was an incredible first spring trip into this amazing wilderness."