Page:The Music of the Spheres.djvu/96

 to become unduly excited) that this star is so far away that such a conflagration would only mean the gradual appearance of a star where none had been visible before, and then its gradual disappearance.

Myra is indeed so far away that we are just 23 years behind time in seeing each explosion, for it takes 23 years for its light to travel to our eyes. If the roar of the conflagration could be heard here, however, the sound would not reach the earth for many millions of years, for sound travels much more slowly than light.

Because of the variation of its light, which is very excessive in the case of Myra, this star is called a variable star. Our sun is also a variable star, but it is variable only in a very slight degree as compared with the exuberant combustibility of Myra. But the theory of spots which are believed to be responsible for the almost imperceptible variation in the light intensity of our sun does not altogether explain the phenomenon of Myra's variability and its mystery is still as great as ever.

Thus is ended the story of Perseus and Andromeda and many of the interesting bits of information connected with the constella-