One of the signs of the onset of the end of this world; the final, three-year-long winter (with no intervening summers), it marks the coming of the Ragnarok, the battle that will end the world.

In a Snowball Earth, ice stretches all the way from the poles to the equator, the oceans freezing over. Norse mythology has a word for it: after Fimbulwinter, the ‘winter of winters’ in which the Earth wasRead More...