The plasma mass reportedly had a quiet center, multiple arms, and a "trend of anticlockwise rotation." In addition, it "rained" electrons instead of water droplets several hundred kilometers over the North Pole. The event -- which occurred during low solar and otherwise low geomagnetic activity -- lasted almost eight hours before gradually breaking down. Its features reportedly resemble a "typical hurricane in the lower atmosphere," which has been observed in the lower atmospheres of Mars, Jupiter and Saturn. Similar phenomena have been spotted on the sun, known as solar tornadoes. In an accompanying release, Reading Professor Mike Lockwood said that just being able to prove the existence of plasma hurricanes is "incredible."