The Stars in Their Courses
THE best remedy for an undue tendency to worry over merely human and earthly problems would surely be a careful perusal of Sir James Jeans' fascinating description of the universe. It assists our sense of relative values to be informed that the sun which warms and enlivens our planet is but an average speci- men of the 100,000 million stars which probably form our galactic system, whilst there are at least two million similar systems scattered through that portion of space which our telescopes can pierce. The most distant of these vast nebulae is so far away that light, travelling 186,000 miles in a second, takes 140 million years to cross the gulf of space that divides us from it. To realize the meaning of these simple statements is almost as hard as Alice thought it was to believe an impos- sible thing, but it is a wholesome mental discipline to make the attempt.
A moderate acquaintance with the immensities and the infinities of astronomy should prevent us from taking the daily worries and the petty miseries of life too seriously. At first the brain reels a little in the attempt to grasp the facts of the stellar system, even explained with the lucidity and exactness of which Sir James Jeans is a master. From the vast exten- sions of the sky he carries us into the inmost recesses of the atom, where the electron whirls round its perpetual circuit several thousand million million times every second. These numbers are but dazzle-painting, and it is simpler to say that the electron travels as far in a second as our latest seaplane travels in an hour. Sir James Jeans has a happy fertility in such comparisons, and forcibly strikes the imagination when he tells us that if the carbon atom were magnified to the size of Waterloo Station its electrons would be represented by six wasps flying round in that vast vacuity. All the rest is emptiness ; and so in the celestial spaces it is immense odds against any given spot being occupied. " We live in a gossamer universe ; pattern, plan and design are there in abundance, but solid substance is rare."
Sir James Jeans has amply fulfilled his ideal in making this account of modern astronomy " intelligible to readers with no special scientific knowledge." If it is a trifle overwhelming to read at one sitting, that is simply because of the gigantic data and concepts which it introduces to the lay reader. We learn that the age of the universe can now be calculated with fair certainty by several diverse trains of reasoning, and that it is probably about five million million years since what may be reasonably called the Creation. The earth, however, is not More than 2,000 million years old as a separate planet. All this time the great machine of the cosmos has been kept going by the annihilation of matter—or rather by its change into radiation. The sun, for instance, is thus losing weight at the rate of four million tons a second, 650 times the rate at which water pours over the Falls of Niagara, but it will last for another fifteen billion years, or more than three times as long as it has' already existed—barring accidents ! As far as astronomy -can tell, the duration of human life on the earth may be at' lefist a million million years. It depends on the reader's temperament, no doubt, whether he finds this an appalling or a consoling thought. We may prefer to take refuge in the thought of the other stars, differing from one another in glory, of which Sir James Jeans tells us so many wonderful things : S. Doradus, which is 800,000 times as luminous as the sun, and Wolf 359, which is only a fifty- thousandth part as bright as our luminary ; Van Maanen's star, which is no bigger than the earth, and the giant orb of Antares, inside which our whole orbit round the sun could be comfortably stowed away. Still more amazing are those extremely dense stars in which a ton of matter could be put into a matchbox or a thimble. If any of these stars have planetary systems and intelligent dwellers on them, do they ever envy us in our " point of peaceful light " ?
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