The Pleiades are one of the finest and nearest examples of a reflection nebula associated with a cluster of young stars. The cluster itself is a group of many hundreds of stars about 400
light years from Earth in the northern constellation of Taurus and has been recognised since ancient times. Seven of the brightest stars are quite easy to see with the unaided eye and bear the names
of the Seven Sisters, the daughters of Atlas. The nebulosity seen here is light reflected from the particles in a cloud of cold gas and dust into which the cluster has drifted. It appears blue
because these tiny interstellar particles scatter blue light more efficiently than the longer wavelengths of red light and it is streaky because the particles have been aligned by magnetic fields
between the stars. |