A way of finding out how old volcanic rock is.
Potassium/argon dating
Fact of the Day
Elizabeth I could cost her hosts so much on her visits that some tried to shut up their houses and stay away to prevent it. This did no good for the earl of Lincoln: Elizabeth broke into his Chelsea residence, had a feast, and then charged the bill to Lincoln.
Quote of the Day
"The Americans cannot build aeroplanes. They are very good at refrigerators and razor blades.
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~ Hermann Göring
On This Day
1284 The future Edward II was born at Caernarfon Castle, Wales. He was the only son from Edward I's first marriage to Eleanor of Castile to outlive his father.
1719 The much-loved Daniel Defoe story Robinson Crusoe was published.
1792 French highwayman Nicolas Jacques Pelletier became the first person to be executed by the guillotine.
1915 Ninety thousand Australian, New Zealand, British and French forces began landing on the Turkish Gallipoli Peninsula. They hoped to secure the northern bank of the Dardanelles, but were forced to withdraw after eight months of intense fighting.
1916 British authorities declared martial law in Dublin for a month, in response to the Easter Rising.
1984 David A. Kennedy, son of Robert F. Kennedy (of the political Kennedy family), died of a drug overdose in Palm Beach, aged 28.
1990 The US shuttle Discovery released the Hubble Telescope into orbit. It remains one of the largest, most versatile and best known space telescopes.