The Mystery of Mars 1 



By H. P. Wilkins, F. R. A. S. 



President, International Lunar Society 

 London 



[With 2 plates] 



Mars is preeminently the planet of mystery. Because it is farther 

 from the sun than the earth, it takes longer to complete a revolution, 

 and every two years we overtake it, when it shines in the sky as a 

 bright red star. The red color, suggestive of war and carnage, was 

 the reason why the name of Mars, the Roman god of war, was attached 

 to this planet. The red color of Mars contrasts strangely with the pure 

 white of Venus or the silvery luster of Jupiter and is too pronounced 

 for anybody to mistake it. 



Although to the unaided eye Mars seems merely a bright star, 

 a good telescope reveals it as a small full moon, that is to say, we can 

 see the face or disk of this little world. We say "little" because Mars 

 is much smaller than the earth, being in fact only 4,200 miles in diam- 

 eter. A telescope shows certain markings on the disk, and they move 

 in the course of an hour or two, which proves that Mars turns on its 

 axis and has days and nights just as we do, although they are longer. 

 Instead of turning around once every 24 hours as the earth does, Mars 

 requires an extra 37 minutes 22.654 seconds, so that although a smaller 

 world it does not spin round so quickly. 



Mars has seasons similar to those of the earth but much longer. 

 They are also more pronounced, because the mean or average distance 

 of Mars is 48.6 millions of miles farther from the sun than that of the 

 earth. From Mars the sun must look smaller, and gives out a pro - 

 portionally smaller amount of light and heat ; we would expect Mars 

 to be a colder world. Mars has an atmosphere, but it is much more 

 rarefied than ours, and it seems safe to say that we would not be able 

 to breathe it because of the deficiency of oxygen, most of which seems 

 to have been absorbed in chemical combination with the surface rocks. 



When Mars is comparatively near to us it makes a beautiful picture 

 in a really good telescope. At such times we see a yellowish-red disk, 



1 Chapter 4 of "Mysteries of Space and Time." Reprinted by permission of 

 the publishers, Frederick Muller Ltd., London. 



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