FLUSH OF DAWN.

Auckland Star, Volume LIX, Issue 177, 28 July 1928, Page 10 (Supplement)

FLUSH OF DAWN.

INEXPERIENCED HUMANITY. A VERT RECENT APPARITION. CIVILISATION" AND THE UNIVERSE. If the proper study of mankind is man, it ought to take the distant as well as the nearer view. Man can project himself into tho stellar depths, and regard his own affairs as through a telescope. "What is it all but the trouble of ants in the gleam of a million million of suns ?" asked Tennyson in a mood of detachment from human struggles, vain aspirations and baffled hopes. The calculations of astronomers and physicists give ground for the belief that the human race is ultimately doomed, because the universe is melting away in radiation. The stars —of which the sun is an example—will grow cold, and cease to flood our earth with life-giving warmth and illumination.

But happily that day is far distant — much too remote to influence anyone's conduct or habits in the present. Although during five million years the mass of the sun's energy has been vastly diminished—through the annihilation of electrons and protons—there are enough unexpended stores of this "pure bottled energy" to provide light and heat for millions of years still to come. These vast forces at work furnish the subject of a fascinating paper by Professor J. H. Jeans, "The Wider Aspects of Cosmogony," published in a recent issue of "Nature." According to anthropologists ami geologists mail has existed on this earth for 300,000 years, and since the days of our ape-like ancestors some 10,000 generations of men have walked the earth. But the total age of the earth exceeds these 300,000 years. Geology and radio-activity in rocks show it to be more like 2000 million years— several thousands times the age of the human race. Old Mother Earth must regard man as a very recent apparition, yet a million years hence,the sun will still probably be much as now and the earth will be revolving round it much as now.

A New-born Babe. On the astronomical time scale humanity is at the very beginning of its existence—a new-born babe, with all the unexplored potentialities of babyhood; and until the last few moments its interest has been centred, absolutely and exclusively, on its cradle and feeding bottle. It has just become couscious of the vast world existing outside itself and its cradle; it is learning to focus its eyes on distant objects, and its awakening brain is beginning to wonder, in a vague, dreamy way, what they are and what purpose they serve. Jts interest in > this external world is not so much developed yet, so that the main part of its facilities is still engrossed with the cradle and feeding bottle, but a little corner of its brain is beginning to wonder.

Taking a very gloomy view of the future of the liumau race, let us suppose that it can only expect to survive for two thousand milion years longer, a period equal to the past age of the earth. Then, regarded as a being destined to live for three-score years and' ten, humanity, although it has been born in a lionse seventy years old, is itself only three days old.

Our vision of the universe is constantly expanding, but the principle of "generalised relativity"—according to which space is finite, like the surface of the earth—fixes a limit to the expansion. Wireless signals might bo emitted and picked up a seventh of a second later, after travelling round the world. In the same way larger telescopes could take us round the whole of space, and we should see tho stars surrounding our sun by light which had travelled round the universe, not, of course, as they now are, but as they were 100,000 years ago. The astronomer Hubble estimated that 2,000,000 nebulae were visible in the 100-inch telescope at Mount Wilson, and that the whole universe has about 1000 million times the volume of that part of space visible in this telescope. In comparison, the earth is one-millionth part of a grain of sand in a layer of sand spread over England hundreds of yards deep. Our mundane affairs, our troubles and achievements thus begin to appear in correct proportion to the universe.

Big and Little Stars. The faintest star (Waif 359) emits only a fifty-thousandth part of the sun's liglit; the brightest (S. Doradus) emits 300,000 times as much. The smallest known star is about the size of the earth, and a million such stars could be packed inside the sun, with room to spare. The largest known star (Betelgeuse) is so big that 25 million suns could bo packed inside it. We can estimate the ages of stars from the impression that time has made upon them, just as wo estimate the age of a tree from the number of subdivisions of its stem or of rings in its cross section. All methods of investigation establish that stars are millions of millions of years old. Terrific Energy.

Year after year, century after century, for millions of millions of years, tho sun radiates enough energy from each square inch of its surface to keep a 50 h.p. engine continually in action; still hotter stars may radiate as much as 30,000 h.p. per square inch. If this energy were produced by the combustion of coal, the stars would all be completely burnt out in a few hundreds of thousands of years. Each square inch of the sun's surface is a searchlight discharging radiation into space; and the sun as a whole is discharging mass into space at the rate of 250 million tons a minute. Each day it weighs 360,000 million tons less.

A quite unusual accident is necessary to produce planets—the approach of two stars —and our sun with its family of attendant planets is rather of the nature of an astronomical freak. In the thousand millions of stars about our sun, there are not more than 10,000 planetary systems; and the birth rate of the latter is about 1 per 1000 million years. Thus we should have to visit thousands of millions of stars before finding a planetary system of as recent creation as our own, and we should have to visit millions of millions of stars before finding a planet on which civilisation, and interest in the outer universe, were as recent a growth as are our own. We are standing at the first flush of the dawn of civilisation, and are terribly inexDerienced beings. The planets are v the only places we know where life can exist. The stars are too hotj even their atoms are broken up by the intense heat. In rare instances, special accidents may produce bodies such aa our earth, formed of a special cool ash which no longer produces radiation, and here life may be possible.