A solar pond is a man-made pool of saltwater that not only absorbs heat from sunlight, but is able to store it for use in heating or power generation. In a freshwater pond, sun-warmed water rises to the top, loses its heat to the atmosphere, becomes denser, and sinks again. In a solar pond, however, a layer of highly salty water remains trapped at the bottom by its own density, even as it is warmed by sunlight—thereby storing heat. Typically, how hot is the bottom of a solar pond?
Back in the day
Built in 1808 and towering over the center of Dublin, Ireland, Nelson's Pillar was a massive monument to Horatio Nelson, Britain's most famous naval hero. It was controversial from the start. In 1966, Irish Republican Army members destroyed the pillar with a bomb. Irish Army engineers then removed the pillar's pedestal with a controlled explosion, which is said to have caused more damage than the original blast. The head of the statue was later stolen from storage. Where did it end up?
Born on a day like today
One of the most important political figures in the history of modern Greece, Karamanlis helped rebuild Greece's economy while serving in various posts after WWII. Chosen as prime minister in 1955, he formed a government and a new conservative party, the National Radical Union. In 1960, he established an independent republic on Cyprus to ease tensions with Britain and Turkey over the island. He resigned in 1963 and lived in exile in Paris until 1974. What finally brought him back to Greece?