Word: ultraviolet
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...March 10, when the sun's stately rotation brought the turbulent group of sunspots to a position more directly facing the earth, a second, only slightly less powerful flare erupted in the region. Eight minutes later, traveling at the speed of light, a blast of X ray and ultraviolet radiation seared the earth's upper atmosphere. Within an hour, high-energy protons began to arrive, followed in three days by a massive bombardment of lower-energy protons and electrons...
Also radiating from the solar surface is energy in the form of visible light, ultraviolet and X rays. Enough of this energy penetrates the atmosphere to deliver some 100 trillion kW of power to the earth. Reduced to more comprehensible terms, solar radiation amounts to 1.35 kW falling on every square meter of earth, a number that scientists call the solar constant...
...beneficence, the sun is not too kind to those who, intentionally or not, overexpose themselves to its warming rays. While most of the harmful solar radiation is absorbed by the ozone layer, enough ultraviolet light gets through the atmosphere to endanger the unwary...
...Helsinki the conferees were following the lead of the U.S. and European Community, which agreed to a similar proposal earlier this year. The new sense of urgency stems from the growing recognition of the importance of the stratospheric ozone layer. It absorbs some of the sun's ultraviolet radiation, which has been linked to skin cancers and cataracts...
...problem may be that the threat is indisputable. Strong evidence of the effect emerged in 1985, when British researchers announced the existence of a seasonal "hole" in the ozone layer over Antarctica. That was worrisome: ozone between ten miles and 30 miles up absorbs the sun's ultraviolet radiation, which has been linked to cataracts, skin cancers and weakened immune systems in humans and other animals, as well as to damage to plants. Data-gathering flights in the Antarctic in 1987 made the connection between CFCs and ozone destruction all but certain. After a similar expedition through Arctic skies last...