In the last post ( we saw how a 22 degree solar halo was created from hexagonal column crystals of ice. These crystals take all different orientations in the sky and thus give rise to the light that reaches

(taken by me back in 2008) A photon is produced in a fusion reaction at the centre of the sun a million years ago. It whizzes out, carrying momentum, and soon after it has left the fused atoms, it collides

Legend has it that just as the sun sets, if the conditions are perfect, then you will see a brilliant flash of green. Such phenomena have been talked about by sailors and travelers for centuries. With