xMagnetic polarity reversal : A magnetic polarity reversal is a change of the earth's magnetic field to the opposite polarity. This has occurred at irregular intervals during geologic time.
In the spring of 2010, the eruption of a volcano called Eyjafjallajökull in Iceland cancelled many flights in Europe. Eyjafjallajökull is a glaciovolcano, which means it's a volcano that is covered by...Read more