In tanks in the lab, they simulated the sun passing over the ocean during the course of a day, and they used a custom -
built polarimeter to measure how the lookdowns reflected the polarized light.
One group, Nat Gopalswamy of NASA's Goddard Spaceflight Center in Greenbelt, Md., and his colleagues, will test a new version of an instrument called a
polarimeter,
built to measure the temperature and speed of electrons leaving the sun.