Page:The Music of the Spheres.djvu/279

 The entire surface of Mars is about equal to the land surface of our earth. The density of the planet is only 73% that of the earth and the force of gravity on its surface is 35% as great as on the surface of our world. The lesser force of gravity, also the lower temperature and rare atmosphere, would all have their influence on any life found on Mars with the result that beings found there might be constituted physically in a very different way from ourselves. The temperature of Mars was computed lately at the Mount Wilson and the Lowell observatories and the results obtained at the two observatories were in excellent agreement. Although it was found to be 94 degrees below zero at one pole and 96 degrees below zero at the other pole, the average temperature on other parts of the planet during the brightest parts of the day averages between 40 to 60 degrees F. This would be a livable temperature for life as we know it, although another fact is commented upon which might cause curious complications. Since the blanket of air surrounding the planet is not of sufficient thickness to hold the heat on the planet, most of it may escape during the night-time, thus causing the temperature to drop to over 112 degrees below zero. If intelligent life wished to survive from day to day it would have to hibernate, perhaps in heated underground galleries, during the night half of its existence. The question as to whether or not there could be life on this planet has been hotly disputed by astronomers for years. It is certainly one of the most interesting aspects of astronomy to the public at large. It is often argued that since Mars is smaller than the earth it must have cooled down millions of years before the earth reached a similar stage, and that its organic life must therefore be proportionally farther advanced. Others have contended that it is past the age where it would be able to support life of any kind.

Professor W. H. Pickering has advanced a new speculative theory called "The Theory of Aerial Deposition." According