Snowball Earth is a strongly disputed hypothesis developed to explain sedimentary glacial deposits at tropical latitudes from the Cryogenian period. The hypothesis proposes that, about 800 million years ago, the Earth was entirely covered with ice and that multicellular evolution accelerated when the climate began to warm up. Some dispute the feasibility of an entirely frozen ocean and prefer a â€œslushballâ€ scenario to explain the ice's rapid movement. How could life survive in such a climate?
Lucy Maud Montgomery
Back in the day
Joan of Arc was a French military leader and heroine who was canonized as a saint in 1920, nearly 500 years after she was burned at the stake. Inspired and directed by religious visions, Joan organized the French resistance that forced the English to end their siege of OrlÃ©ans in 1429 and led an army to Rheims where she had the dauphin, Charles VII, crowned king. Captured and sold to the English by the Burgundians, she was later tried for heresy and executed. What was the "nullification trial"?
Born on a day like today
One of the most influential guitarists in the history of rock music, Page started his career as a highly sought-after studio guitarist in England. Under his direction, Led Zeppelin became one of the era's most successful rock groups, redefining the musical sound of the 1970s. Page has co-written many popular rock anthems, including "Stairway to Heaven," a song that has been the subject of controversy since reports that it contains a subliminal message surfaced. How does one hear the â€œmessageâ€?