The Seven WISE Sisters

If you live in the northern hemisphere and go outside in the winter, hanging not too far from Orion's left shoulder is a small, tight, configuration of stars. A lot of people mistake them for the Little Dipper -- I get asked about it all the time -- but really it's the Pleiades (pronounced PLEE-uh-dees), an actual cluster of stars about 400 light years away. To the eye you can usually spot six of the stars (the seventh, seen in ancient times, may have faded a bit since then), and in binoculars you can see dozens. But when NASA's Wide Field Infrared Survey Explorer (WISE) looked at it in February, this is what it saw: