Pleiades, a star cluster formed about 100 million years ago. Each of them is some 40 times brighter than our Sun. And Alcyone, the most luminous, outshines our Sun 1,000 times. For ages, the Pleiades have been used as an eye test for people all over the world. If you could see at least six of them, you were considered normal. If you saw more than seven, you were an ideal candidate for a warrior or scout. Among the ancient Celts and Druids of the British Isles, the Pleiades were believed to have a haunting significance.