EXOTIC GREEN FLASH: Seaside photographers have a special fondness for the sunset. On rare occasions they can catch the elusive green flash--a split-second pulse of verdant light that signals the disappearance of the sun beneath the ocean waves. On April 7th, astronomy professor Jimmy Westlake photographed a green flash as he stood atop Hawaii's Mauna Kea volcano. The flash he saw, however, did not come from the ocean waves. It happened in the clouds.
