TIME OF THE MOON'S BIRTH.

Auckland Star, Issue XXXVI, 21 October 1905, Page 9

TIME OF THE MOON'S BIRTH.

Discussing the time occupied by the sequence of evolutionary events sketched, Professor Darwin said that if .at every moment since the birth of the moon tidal friction had always been at work in such a way as to produce the greatest j possible effect, we should find that 60 ! million years would be consumed in this j portion of evolutionary history. The i true period must be much greater, and it did not seem unreasonable to suppose : that 500 to 1000 million years might have elapsed since the birth of the moon. Such an estimate would not seem extravagant to geologists. Pure geology pointed to some period between 50 and and 1000 million years, the upper limit being more doubtful than the lower. Thus they did not find anything which rendered the tidal theory of evolution untenable. Dealing with the different estimates of the physicists and the geologists. Professor Darwin said that from a calculation of the snn's total output of heat, it seemed to be imperatively necessary that the whole history of the solar system should be comprised within some 20 MILLIONS OF YEARS. Por the last 40 years the physicists had # been accustomed to tell the geologists that they must moderate their claims, but for himself he had always believed that the geologists were more nearly correct. And now, at length, relief had come to the strained relations between the two parties, for the recent marvellous discoveries in physics showed that concentration of matter "was not the only source from which the sun might draw its beat. Radium was a substance which was perhaps millions of times more powerful than dynamite. Thus it was estimated that an ounce of radium would contain enough power to raise 10.000 tons a mile above the earth's surface. Another way of stating the same estimate was that the energy needed to tow a ship oi 12,000 tons adistaace of 6000 sea miles at 15 knots [was contained in 22 ounces oi radium. The Saxon probably hurned five or six thousand tons of coal on a voyage of I approximately the same length. Now, Iwe knew that the earth contains radioactive materials, and it was safe to asjsume that it forms in some degree a [sample of the materials of the solar system; hence it was almost certain I that the sun is radio-active also. This I braaxjh of science was yet in its infancy, but they already saw how unsafe it was Ito dogmatise on the potentialities of 'matter. It appeared, then, that the physical argument was not susceptible lof a greater degree of certainty than that of the geologists, and the scale of geological tune remained in great measure unknown.

THE STELLAR TJNIVEKSE. Passing on to the wider fields of the stellar universe. Professor Darwin referred to tbe inconceivably vast multitude of stars and nebulae revealed by photography. A celestial photograph, he , said, looked at first like a dark sheet of 'paper spfeshed nrifca wttiewaso, hut further examination showed that there was I method in the arrangement of the white spots. Tims there was order of soma sort in the heavens, and it -was possible | to obtain general ideas as to tbe succession of events in stellar evolution. The conviction was forced on them that the ! wispy donds represented the earliest stage of development, the more conjdensea. nebulae a later stage, and the I stars taemserres the last stage. Change was obvioßsry in progress everywhere, i as well as in each individual nebulae and star as in tbe positions oi those bodies

relatively to one another. But they were unable even to form conjectures aa to the tendency of the evolution which was going on. In conclusion, Professor' Darwin, said: '""We have seen that it ia possible to trace the solar system back to a primitive nebula with some degree of confidence, and that there is reason to believe that the stars in general have originated in the same manner. But such primitive nebulae stand in as much need of explanation as their stellar offspring., Thus, even if we grant the exact truth of these theories, the advance towards an explanation of the universe remains miserably slight. Man is but a microscopic being relatively to astronomical space, and he lives on a puny planet circling round a star of inferior rank. Does it not, then, seem as futile to imagine that he can discover the origin and tenjdency of the universe as to expect a I housefly to instruct us as to the theory of the motions of the planets. And yet, so long as he shall last, he will pursue hi 3 search, and will no doubt discover many wonderful things which are still hidden. We may indeed be amazed at all that man has been able to find out, but the immeasurable magnitude of tho undiscovered will throughout all time remain to humble his pride. Our children's children will still be gazing and marvelling at the starry heavens, bus the riddle will never be read."