September 19, 2003

THE DARK SIDE OF THE MOON
Não se trata desta vez de nova edição do clássico álbum dos Pinkfloyd, mas sim dos resultados de uma investigação científica divulgado pela revista Scientific American graças aos dados recolhidos pela sonda Shandra nos últimos meses: "We have moon samples from the six widely-spaced Apollo landing sites, but remote sensing with Chandra can cover a much wider area," he remarks. "It's the next best thing to being there and it's very fast and cost effective." He presented data from Chandra collected in July and September 2001 that indicate the presence of oxygen, magnesium, aluminum and silicon over a large area of the lunar surface. When solar radiation hits the moon, it excites some of the elements' electrons. This energy is quickly reemitted by the elements at a characteristic wavelength in a process known as fluorescence, which Chandra detects.