717 CE - The Byzantine navy uses Greek fire to defeat an Arab armada of over 2,500 ships, thus lifting the Siege of Constantinople during the Arab-Byzantine wars.
Photo of the Day
Henequen farm in the Yucatán Peninsula.
In the News
Putin Calls for Talks on East Ukraine 'Statehood'
Iraqi Forces Break Two-Month Siege of Amerli
Pakistan PM Still Surrounded by Protesters After Deadly Clashes
Libyan Armed Faction Takes Over US Embassy Annex in Tripoli
Rebels in Central African Republic Expel Government Ministers
Iraqi Forces Break Two-Month Siege of Amerli
Pakistan PM Still Surrounded by Protesters After Deadly Clashes
Libyan Armed Faction Takes Over US Embassy Annex in Tripoli
Rebels in Central African Republic Expel Government Ministers
Quote of the Day
"A difference which makes no difference is no difference at all". --William James
Song of the Day
Artist - The Heptones
Album - Book of Rules
Film of the Day
Director - Tim Burton
Starring - Michael Keaton, Jack Nicholson
Wiki of the Day
Californium is a radioactive metallic chemical element with the symbol Cf and atomic number 98. The element was first made in 1950 at the University of California Radiation Laboratory in Berkeley, by bombarding curium with alpha particles (helium-4ions). It is an actinide element, the sixth transuranium element to be synthesized, and has the second-highest atomic mass of all the elements that have been produced in amounts large enough to see with the unaided eye (after einsteinium). The element was named after the university and the state of California. It is the heaviest element to occur naturally on Earth; heavier elements can only be produced by synthesis.
Two crystalline forms exist for californium under normal pressure: one above and one below 900 °C (1,650 °F). A third form exists at high pressure. Californium slowly tarnishes in air at room temperature. Compounds of californium are dominated by a chemical form of the element, designated californium(III), that can participate in three chemical bonds. The most stable of californium's twenty known isotopes is californium-251, which has a half-life of 898 years. This short half-life means the element is not found in significant quantities in the Earth's crust.[a] Californium-252, with a half-life of about 2.64 years, is the most common isotope used and is produced at the Oak Ridge National Laboratory in the United States and the Research Institute of Atomic Reactors in Russia.
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