I’m hooked on the APOD site now. It’s a real wonder. First I went to gawk at the pictures, then I discovered that the prose and links at the bottom are also very good. For instance, I found this cool Soviet propaganda booklet about Yuri Gagarin. Ever wonder why stars in astronomical photographs look like they have four spikes sticking out of them? Find out why: APOD: 2001 April 15 – Diffraction Spikes: When Stars Look Like Crosses. The spikes article led me to the Nobel Prize site, which has some tasty articles about physics: Nobel e-Museum.