The Birmingham age-herald., 1924-07-20

prospective approach to less than 35,- 100000 miles being unequalled by any approach in two centuries, and will not be equalled during the lifetime of any man now living. '..
 Requires Longer Trip
 The reason for this variability of dis tance is that Mars is much farther from the sun, and so it takes him long CT to go around once than does the earth. His year is equal to about 687 of our days, or nearly one year and eleven months. For that reason he never stays at the same relative posi- tion with respect to us. We are always 0vertaking him, and when we do catch up every two years or so he is nearer to us than at other times.
 The distance of these near approaches varies because neither the orbit of Mars nor that of the earth is exactly circu- lar. They are ellipses. Sometimes the earth is 100000 miles farther from the sun than at other times, and if 1t happens that the earth catches up to Mars somewhere near that time and at the same time Mars is close to his nearest approach to the sun, it follows that the earth and Mars come nearer together than at any other time. That IS just what will happen in August. Although Mars has been the target of telescopes since they were first turn ed toward the heavsns, much more needs to be known about the physical con- ditions existing on that planet. Its size, density, position and motion with respect to the sun, the length of its seasons and days have long been known with satisfactory accuracy. The ques- tions now interesting many astronomers are those that have been hotly disputed for many years:
 "Is there life on Marsw
 ''Is the planet inhabited by intelli- gent beings?
 First Found "Channels''
 It was in 1877 that the Italian as- tronomer, Schiaparelli, found narrow streaks on the surface of Mars. He called the ''canale," which should have been translated into English as channels" so called because Schiapar- elli believed they connected great dark areas then thought to be oceans. Un- fortunately the word was actually trans lated as canals" term that suggests artificial construction. Hypothetical inhabitants were created to perform these great feats of engineering skill, and the popular imagination was spur red by such thrilling fiction as Wells War of the Worlds" .-.
 Before the canals and their possible construction are considered. let us see what sort of place our next door planet appears to be. ..
 The atmosphere of Mars is much rarer than that of the earth, only one. twelfth the density of the air that we breathe. Astronomers differ as to whether there is water and oxygen on Msrs. Many have concluded that there are ample supplies of both on Mars, but spectroscopic tests made at Lick observatory seem to prove that there is very little of either water vapor or oxygen on the planet.
 Water would boil on Mars at about no degrees Fahrenheit, as compared with PIP degrees here on earth. Gravity at the surface is about 35 per cent, what it is here and man weighing 150 pounds on earth would weigh about 62 pounds on Mars.
 About HaIH Our Size
 The diameter of Mars is little more than half that of our own planet, and it's entire surface area is about equal to the land surface of the earth. From the earth at any one time half of this surface IS exposed to view.
 If small telescope, say one of eight inch aperture and 400 diameters mag nification,J is directed at the ruddy planet, some idea can be obtained as to why there has been so much discus sion about the Martian landscape.
 The most striking of the surface fea- lures of Mars are the white polar caps which vary in size with the seasons of the planet. As the Martain winter ad- vances, the caps increase in size, and when summer comes they seem to melt away. These great white masses may be composed either of snow, such as we have on our earth, or of carbonic acid gas in. the frozen state.
 Those. who hold for the snow cap theory believe that the progressive dark ening of. the surface from the pole to- ward the equator during the melting of the cap is due to the growth of vege- tation on Mars is just opposite that on earth, where the green of vegetable growth follows the advance of the sun from the quator toward the pole, ap- bearing first in low attitudes of the tenn perate zone.
 Causes Spirited Controversy
 The so-called canals of Mars have given rise to the most spirited of. the controversies resulting. from a study of this planet. Prof. Percival Lowell in 1894 built an observatory at Flagstaff, Ariz., for the express purpose of study ing the planet and it's canals, and since that time many careful visual and pho tographic observations have been made there. Out of the intense interest in the surface markings of Mars there has sisn ~rown an organization known as r '.3s:,-- < ,.;sE& -34