November 8, 1895: Wilhelm Roentgen, German physicist, accidently discovered X-rays. While testing whether cathode rays could pass through glass, he noticed glow coming from nearby chemically coated screen. He dubbed the rays that caused this glow X-rays because of their unknown nature. Scientists were quick to realize benefits of X-rays, but slower to comprehend the harmful effects of radiation. Initially, it was believed X-rays passed through flesh as harmlessly as light. However, within several years, researchers began to report cases of burns and skin damage after exposure to X-rays. During the 1930s, 40s & 50s, many American shoe stores featured shoe-fitting fluoroscopes that used to X-rays to enable customers to see the bones in their feet. Today, X-ray technology is widely used in medicine, material analysis, & devices such as airport security scanners. November 8, 2004: Following four years of Arctic study, international team of 300 scientists announced the Arctic is warming at nearly twice the rate as rest of the globe. Subsequent satellite imagery shows a continually shrinking ice cap, with most years scoring new annual lows. What the exact loss of Arctic ice will mean for the worlds future weather & climate is not well understood. Accelerated climate change due to loss of polar reflectivity (albedo) is a major concern. November 8, 1997: Yangtze River was blocked in preparation for world’s largest hydroelectric power project. Benefit was cheap & abundant hydroelectric power in China. Cost was displacement of thousands of people & major ecological impact. November 8, 1931: Fredrick Allison, American chemist, reportedly discovered the heaviest halogen, astatine (atomic number 85). Astatine was first synthesized & correctly identified in 1940 by bombarding bismuth with alpha particles. All astatine isotopes are highly radioactive and very short lived. In the 1920s & 30s, scientists were eager to find the elements 85 & 87, as predicted by Mendeleev’s periodic chart. November 8, 1923: Jack St. Clair Kilby, American electrical engineer, was born. His interest in electronics grew out of his school-age hobby of amateur radio. Working at Texas Instruments, he devised way to miniaturize complicated transistor circuit by building its components on a block of silicon with internal connections that eliminated external wiring. In 1965, Kilbys team developed first shirt-pocket electronic calculator using integrated circuits. November 8, 1656: Edmond Halley, English astronomer & mathematician, was born. He identified proper motion of stars, studied the moons motion & tides, realized that nebulae were clouds of luminous gas among the stars, and that the aurora borealis (northern lights) was associated with the earths magnetism. Halley was first to calculate orbit of comet that was named after him, which makes an appearance every 76 years.
Posted on: Sat, 08 Nov 2014 15:49:04 +0000
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