ASTRONOMICAL NOTES FOR MAY.

Wairarapa Age, Volume XXXII, Issue 3180, 4 May 1909, Page 3

ASTRONOMICAL NOTES FOR MAY.

{By the Rev. P. W. Fairclough, F.R.A.S.. in tbu Christchurch Press).

: Jupiter is still in Leo and near to Regulus, the Lion's heart. The great planet has been retrograding for .some time. That is, owing to themore rapid advance of the earth, Jupiter has been apparently thrown backwards in his path towards Regulus. On the second of the month he will be stationary, and will then begin to advance eastward. Mercury is an evening star, and will be best seen about the 20th. On th e 21st he will be a little north of the new moon. At the end of the month Mars will rise about one in the morning. Rising earlier every night, he will gradually come into the evening sky from the east. Venus will pass behind the sun about the end of the month, and will slowly rise above him in the west, but will not be noticeable for a month or two. The most conspicuous constellation is Scorpio, which can be seen in the east as soon as it is dark. The red star Antares—the false Mars—is in the head of the Scorpion. His claws stretch northward, and his long tail sweeps up and then curves down, southward. Hercules is low in the north at midnight. Last month we discussed otherworld man in a speculative way. We will now consider the habitability of what seems to be the most likely planet—Mars. A. R. Wallace has published a book on the question "Is Mars Habitable?" He is opposed to other-world man. He champions the flattering yet meloncholy idea that this is the only world with intelligent life on it. He may therefore be trusted to say all that can be said against the theory that the cobweb of straight lines observed on Mars are the bands of vegetation irrigated by canals constructed by intelligent beings, with water drawn from the melting of polar snows. We will state his chief objections:— 1. The surface of Mars would require to be almost a perfect level to admit of a network of canals in every direction. Almost all the markings are perfectly straight and are hundreds and, in some cases, thousands ,f miles long. If the surface were level the water from the melting polar snow would spread without canals. If it is no', level, vvhtre would be the intelligence of cutting through hills and tablelands? These, with the water far below the surface, could not be irrigated. 2. Where is the intelligence of carrying long, straight canals through mighty deserts, instead of cultivating large contiguous districts? This is certainly a serious objection to the intelligence of the supposed canal builders. If, tor example, there were a large supply of water along the groat Australian Bight, would it be intelligent work to use it to cultivate straight streaks across the continent in ever direction, leaving desert between? Would it not be far easier and more economical of water to cultivate one large continuous region? 3. The "canals," so-called, have their seasons and change colour, a3 if for spring growth and harvest. Alfo, it is said that the colour of alleged growth begins at the polar end of the canals, hear the melting sr.ow, and advances at about two and a-balt mile ar,d hour toward the equator. This has been explained as the vegetation promoted by the advancing stream. It implies a regular and considerable fall in the surface from the Poles to the Equator, which seems highly improbable. This difficulty is so great that the irrigationists have been obliged to suggest artificial propulsion of the water. But, again, is that possible? Further, the alleged water the north passes over the Equator and invades the southern hemisphere to a considerable distance. In the next season the alleged water from the south similarly invades the northern hemisphere. Thus the water flows both ways! Here again artificial propulsion is suggested. The judicious must surely pause before accepting such facts and such a theory.

4. According to Lowell the sole supply of water is derived from the melting of the polar snows. Owing to the amall gravitating power of the planet this snow would be three times lighter thai) snow on the earth. The falks of snow appaar to be very thin. Clouds are seldom seen, yet the snowcap may be deposited in a very short time, great increases in the area ot the cap being noticed in a single night. Sometimes the snowfall is late, and begins to melt immediately after it is deposited. It will therefore be liberal to allow 20 J feet of snow, whhh, being very light, I will equal one foot of water. The area said to be irrigated is at least seven times the area of the snow caps. This would allow less than two inches of water for irrigation—supposing none to be lost by soakage and evaporation. This inadequate supply ! .of water certainly seems to be a 'serious objection to the irrigation , theory, arid further reflects on the I intelligence of the long, straight threads of cultivation. It should be ; stated that the "canals," in order to j be visible, require to be a few miles wide. One of them is 30 miles wide. Of course it is not pretended that this is the width uf the water-course. It is said to be the band of irrigated vegetation. 5. The atmosphere of Mars is believed to be very thin, equal to I only about two inches of mercury, ( whereas ours is equal to 30 inches. The atmosphere of our highest mountain tops is, therefore, much denser than that or. the surface of the red planet. This poverty of atmosphere must be a great disadvantage to the Martians in several ways. It cannot carry heavy cloud masses, a fact which nupports the idea that the snow-caps are fittle more that a heavy frost. Again, a very small atmospheric pressure increase evaporation, and would lead to a heavy loss of any water that mignt exist. And, again, a dense atmosphere like ours acts as a thejsun's heat. We live in a glass house, which stores the solar rays. Mars receives, owing to his greater distance, only half as much heat from the. sun, as the earth does. With little depth of air and ioyi clouds, he can make but the poorest use of that half supply. Many investigates arrive at

the conclusion that the average temperature of Mars is Delow freezing point. Some think that it is lower than any temneraturo experienced by our Antarctic heroes. If this conclusion should be made good by further research, it will be a most serious objection to the habitability of Mars. Mr A. R. Wallace has his own theory for the "canals'" of Mars as natural features. He admits that the surface is extraordinarily level—which, by the way, answers one of his objections to the canals. Observers have detected no mountains. Now a world like our?, hot in the centre, must, as the centre cools fand shrinks, cause its crust to wrinkle and buckle up into mountains. Wallace thinks that Mars grew according to the meteoric hypothesis, by a slow aggregation of meteors, and never got hot, or cooled, as he grew. When the planet was within, say, 100 miles of his present diameter, he was cold. Then he encountered a great storm of mereoric matter, which fell so thick and fast as to cover him with a molten sea of lava. But the centre was cold, and, as the outer coat of hot material cooled, it cracked in long, straight cracks. Out of these cracks, he supposes, some heavy gas to rise, such as carbonic acid gas, and overflow, causing some kind of vegetation to grow along the sides. This explanation is ingenious, but is almost as improbable as anything it is intended to explain away. The building of a cold planet is difficult enough, but the cataclysmic deluge of metoers which overlay it with molten matter is a bold demand indeed.

Wallace makes much of this fact that water was not. known to exist on Mars at the time he wrote—l9o7. He thinks 'hat the "snow" is frozen carbonic acid gas, and that the clouds, 12 or 15 miles hieh, observed on the planet's edge, are dust from the deserts. Since he wrote the spectroscope has detected the vapour of water in the atmosphere of Mars. This shows that the temperature is not too low for vapour, and that there is water. Clouds of dust so great and high, would also argue a considerable density of atmosphere and strong winds, which is all against his contentions He also argues that so cold and waterless a world could never have produced intelligent beings, and that if they were (produced they would never have had the capital and resources required for such tremendous works. The canal theory, however, supposes Mars to be a slowly dying world which, long ages ago. was well endowed with water As it has cooled and its rocks have crystaiised, they have drunk up the water. The inhanitants, say 100,000 years ago, began to be pinched for water, and began to build, and through ages continued to build canals to enable themsevles to remain in their beloved countries. As the water decreased they abandoned their wide areas of cultivation, but kept main channels open as a means of communication. A planet, far advanced in cooling, would have so thick a crust that it would no longer build mountains by j wrinkling. At the same time the agents of erosion would level the ancient mountains and give the planet an even surface. This would have taken place before the., canal building began. Between Wallace and the canahtes it seems to us that honours are even, and one must wait for further information. Perhaps some reader may ba inclined to test Wallace's speculation, or rather to illustrate it, by taking a cold ball, say of iron, and dipping it in melted wax or tallow till it has a coat, say a quarter of an inch thick. Tne wax must be as cool as possible, so aa not to heat and expand the ball. The ball should then b2 suspended, and set spinning slowly, and left to get thoroughly cold. The wax will probably crack. .We would be glad to know how it cracks—in straight lines, curves, zigzags, parallels, or what not.