41.   Sunlight, or solar radiation, is transformed into power through a semiconductor unit, or PV cell.

42.   The earth failed to cool off quickly because the high levels of carbon dioxide in the atmosphere kept trapping lots of solar radiation.

43.   The enclosures contained samples of paint and optical materials that were left exposed to space, including micro meteoroids, solar radiation and a reactive form of oxygen.

44.   The external influence could be either natural, like a change in solar radiation, or artificial, like carbon dioxide emissions.

45.   The device, a portable reflectometer, was designed to measure deterioration in the hull after long exposure to solar radiation and other corrosive elements.

46.   The new buildings will be heated with heavy summertime doses of solar radiation -- and in the winter, jet fuel and possibly wind power.

47.   The original material has deteriorated faster than NASA anticipated from its exposure to solar radiation.

48.   The natural ones include changes in solar radiation, and sulfate droplets called aerosols cast aloft by erupting volcanoes, which cool the atmosphere by reflecting sunlight.

49.   The researchers reached this conclusion by analyzing changes in solar radiation absorbed by plants as they perform photosynthesis.

50.   The ozone layer normally provides a shield from cancer-causing solar radiation.