A PEEP AT MARS.

Auckland Star, Volume LVIII, Issue 274, 19 November 1927, Page 36

A PEEP AT MARS.

OUR NEXT DOOR NEIGHBOUR.

IS IT INHABITED ?

SINISTER INTEREST OP THE

CANALS

On August 22, 1924, the planet liars was closer to the earth than it had been in more than a hundred years. Not for many years to come will the two planets, swinging through space on their dissimilar orbits, again reach positions so favourable for observation. Astronomers, who keep accurate record of the movements, past and future, of the planets, have long known that the earth and Mars in 1924 would be in more favourable juxtaposition so far as observation is concerned than at any time since the development of the modern telescope.

In observatories throughout the world, therefore, astronomers for months had been preparing to take the fullest advantage of the planet's approach in 1924. It was hoped that some new facts might be added to the slender store of our knowledge of this most interesting of our celestial neighbours. The facts they hoped to learn, however, were not very exciting to the lay mind. They had no expectation of making sensational discoveries or settling the question as to whether Mars is inhabited, or whether the so-called ' canals" are of natural or artificial formation; nor indeed did they hope to prove definitely if the areas on the planet's surface which are assumed to be water and vegetation actually are water and vegetation, or something else. The hope that some communication between the planets might be established, they dismissed as too fantastic. "Why," the public asks, "do astronomers hesitate to say definitely whether or not Mars is inhabited ?" I

Here are some facts that will go a long way toward explaining their "excessive caution": The distance separating the earth from Mars during the time of their closest approach in August, 1924, was 34,600,000 miles. This is a distance more than 4000 times the diameter of the earth.

A Disc of Light.

On the date of its nearest approach Mars, when regarded with the naked eye, was a mere pinpoint of light in the firmament. It was distinguishable only by its scintillations; the body of the planet itself was invisible. Magnified by the powerful thirty-inch lens at Lick Observatory, and further enlarged by an eyepiece, Mars looked smaller, farther distant, than the full moon appears to the unaided eye. Seen through the huge telescope, the planet was a distant, vibrating disc of light,, faintly reddish in colour. The untrained eye could distinguish nothing of its details beyond the polar cap, a lighter spot at one edge of the disk, and here and there certain darker areas. Observation is uncertain and difficult even to eyes trained to telescopic observation, and for that reason much of the study of Mars is made from photographs taken through the telescopes. _ Each glass, about 3 by 4 inches in size, contained from six to ten exposures of the planet. The image of Mars registered on the plate had approximately. the diameter of a lead pencil. Is it surprising that astronomers, working from photographs, of this size hesitate to inake rash statements as to what will be found there? The photographs, to be sure, can be enlarged, but only to a certain point. Beyond* that point the image loses sharpness of outline anil further enlargement results in less, rather- than greater, clearness. This distinction between fact and theory , in regard to our knowedge of Mars has not been made sufficiently clear, to the public at large. For instance, astronomers say that the surface of Mars sLows certain markings 'which bear a resemblance to thin, dark .lines. This is fact. The existence ;of the markings has been proved by many photographs, by the independent observations of scores of observers. When, however, one says that these markings are water, that they are "canals," that they are artificial rather than natural, one jutnps from the basis of known fact into the realm of theory and inference. Th'ere is at present no proof that, the canaln are water; scientists merely say that > such markings might be caused by water. To' be visible at all from the earth it is probable that they would have to be at least two hundred- miles wide. To many this would indicate that they are not of artificial ~ construction.

.0;:; _ Snow-capped Poles. Similarly, the photographs of Mars show a lighter area ait each of, its poles. These areas are known to vary in extent at different seasons of the year. The natural assumption is that these polar areas are enow, though with the present means of observation there is no possibility of determining this for certai&C Aga : i, observation shows that at certain seasons of the year, at the period when the polar caps are smallest in extent, broad -strips appear about the bases of the caps and take on another colour, and that these strips fade out again after a few months. To many observers these strips appear to have a green tint. When an astronomer leaves fact and indulges in theory, he says that these areas might be vegetation which springs '■ up as the snow caps melt and recede, and which presently dries up and dies. Let us see how ~ the astronomer approaches the question about which we all have the keenest curiosity: Is there life on Mars? '

His frank answer is that he doe 3 not know, and that upless our present means of. observation can be enormously improved, he can see no possibility ever of knowing. Asked not what he knows but what he thinks, what his theory is, he will probably draw his inferences ,in about this way: If the polar caps which are plainly visible are actually snow, then it is. probable that the darker areas tyhich appear about their bases are caused by the growth of vegetation. From our Observations of the distribution of life on the earth we know that vegetation does not exist here without the presence of some form of animal life. Of cdiirse, we are not sure that this, rule applies also to Mars, but it seems more probable than, otherwise. Therefore, provided the area we speak of actually is vegetation, it seems likely that some form of animal life must also exist there:

This does not mean, that the many scientists who believe thpt life, and life of a high order, exists on Mars are not able to . marshal .a, considerable mass of circumstantial evidence in support of their, theory. The best known spokesman 'of .this'. groiip was Dr. "Percival LoWell, for-many years the director of the observatory at Flagstaff.

A Struggle for Water. Dr. Lowell's belief that Mara is inhabited by a highly intelligent race is largely based -upon his study of . the thin dark markings, the canals, of the planet. Thfc peculiar straightnesa of these lines, the fact that they apparently are unvarying in width, their extreme length and their distribution over the surface of the planet led him to believe that they could not be of natural formation. Nature, Jte argued, does not create such straight lines upon the earth or upon such celestial bodies as can be studied. Why, then, should we believe that Mars is the exception? If one accepts the theory that the Martian cana}s are not of natural form-, ation it must of course be assumed that they are artificially made. The natural question then arises. Why? Dr. Lowellj set about to discover a valid reason that would account for the necessity for so stupendous an undertaking. He found that necessity in the known fact of the light atmosphere of Mars, demonstrated by its almost complete lack of clouds. This, combined with other evidences points to the highly probable conclusion that the planet possesses very little water, and that such water as exists is confined very largely to the polar regions.

His deductions from this point are easy to follow. W&t-jr is a necessity to life as we know it; existence depends upon it. Where it is scarce the struggle for existence becomes, in effect, a struggle for water. "The study of plane try evolution in general," writes Lowell, "shows that as a planet age 3, its surface water grows scarce. Its oceans dry up, its rivers cease to flow, its lakes evaporate." This process, he argues, has advanced much farther on Mars than it has on the earthj to the point indeed, where water becomes a very precious commodity, its proper conservation and distribution vitally necessary to all life on the planet. Seen in the light of this theory, the canals of Mars take on a significant and sinister interest. They become evidences, visible through millions of miles of space, of the tremendous struggle which the life of another plant is waging for its continued existence.

Here is theory intensely interesting, one believed to be . probable by many competent scientists. Is it true! Shall the question ever be settled for certain? Will inference be replaced by certainty, theoretical belief superseded by scientific knowledge? A statement by Dr- Robert G. Aitken, associate director of tick Observatory, has a bearing on this question. "The largest telescopic lens in existence to-day," says he, "is one hundred inches in diameter. It costs one million dollars. With a' lens three hundred inches in diameter we might hope to learn if life exists on Mars. Such a lens, howwould cost, not three millions of dollars, but twenty-five millions. We are not likely to have it soon."