THE POETRY OF SCIENCE.

Gisborne Times, Volume XXVIII, Issue 2705, 8 January 1910, Page 3 (Supplement)

THE POETRY OF SCIENCE.

IV. THE SPECTRUM. (By Professor A. W. Bickerton.) If we look with a prism of glass at a beam of sunlight reflected from a silver bead, the shining spot becomes a strip of many-colored light, as though, we had. cut a ribbon from across a rainbow. A beam of sunlight is a bundle of beaivtiful threads of all colors that, seen together, look white. • The prism has the power to bend the beam, but it bends some colors more than others, and so sorts the ray of light- into its constituents, bonding the violet most and the red least. There are strands it bends more than the violet, but the eye cannot detect them. Yet they will tell or their presence on the photographic film. Light consists of waves of a substance called other, which is everywhere. It reaches from the earth to the sun, from star to star. A beam of white light is like a many-colored thread of wool, its structure is wavy, and the various colors are of different fineness. The red is like coarse wool, the waves arc long, the violet is shorter, and those outside the..violet the shortest of all. When the'light has passed through the prism, we call the “rainbow-tinted streak” the spectrum, and in it the waves are all in order, assorted according to length. If we look through a prism at the colored lances of a set piece of fireworks every lance is a spectrum, but the spectra vary according to the color. Each burning lance shows bands of its especial color, and the exact place of the hands on the tinted ribbon tells by the atomic speed of vibration the actual metal that is being burnt and is giving color to the different flames. STELLAR SPECTRA. 'this detection of metals and other chemical substances by the light they give through a prism is called spectrum analysis. It is the most delicate andwonderful of all kinds of analysis. By its aid we can detect the ten thousandth part of a grain of common salt. AYe can examine the light of the sun, of stars and of nebula, and tell whatthese distant bodies are made of, and not only what they are made of but much more information, for tile lines alter in character by pressure and by. motion. They alter when tho sun 3s eclipsed or full, alter if the body is spinning or at rest; so that astronomical spectrograms are veritable telegrams telling us the story of the stars. WHAT THE STARS TELL US. The message sent by new stars is very complex, and astronomers find it hard to read, and differ much as to wliat it is saying. The wonderful thing about the third body theory of the origin of new stars is, that it’ told in the minutest detail ail the physical agencies that would produce exactly the kind of spectra that is now actually seen, and did it a dozen years before the astronomers had photographed them. The commonest element that shows itself in star spectra is hydrogen, and although tile same story is told by other elements, hydrogen generally tells it best. Of course, our theory of the origin of new stars is that dead suns have come into partial impact, have had a piece cut from each, the pieces have coalesced into an exploding new- star, and tlio two suns go on their way with fiery scars. According to Professor Simon Newcomb in “Sidelights on Astronomy, ' page’ 21, new stars are the most astonishing phenomena of Nature, and as inexplicable as they aro wonderful. Th© theory of partial impact does not lesson their wonder, but most- certainly takes away their mystery. These bodies me sometimes scores of thousands of limes the brilliancy of the sun. CHARACTER OF NEW STARS. According to deductions from this theory, if they are the third bodies formed by the grazing impact of dead suns, new stars should have certain well-defined characteristics. They should appear suddenly, actually in less than a hour, grow brighter for a week or so, diminish for a icw months, then disappear by dissipation into concentric planetary nebulae. They should give at first a stellar spectrum crossed with black lines, displaced towards the violet. After a few days they should give broad, bright bands, these blaze bands being shadowed on the violet side by absorption lines, the bands of hydrogen should be wider than the helium bands, and the displacement of the black lines of hydrogen greater than that of helium. In all other elements the bands will be narrower than the helium bands, and the displacement of the black lines proportionately- less, being narrower as the atomic weight of the element is heavier.

After some time the black bands would die out. Then the bright bands of hydrogen and helium should also die out. and as the bands of tlie elements of tlie low atomic lesson, bright lines of heavier elements should show themselves, especially those having no affinity for oxygen, as nitrogen, neon, argon, etc. If 'the graze of the dead suns be a,deep one, these may form a permanent planetary nebulae. A.- the speed at which the hydrogen atoms expand into a shell will not appreciably lesson, the width of the blaze bands, and the displacement of the dark hydrogen lines should not appreciably diminish, even when they die out. The helium would not lessen much, but any dark lines tending to permanency should diminish and have finally but slight- displacement, and the permanent bright band should be narrow. Finally an object showing a fluctuating light- may be left after all else has- cisappeared. In very deep grazes variable and double stars may be left, as may also meteoric swarms, and ultimately star clusters. An examination of the obscured facts about new stars and their spectra confirms almost every one of these deductions, thus wiping away every, trace of the mystery that has interested men from the dawn of history:.; ' ; V , It, was the blaze of an immense star in the Scorpion that caused Hipparchus tp draw up his historic list of the stais. It was this wonderful Pilgrim, star; that brilliant temporary of 1572, that made the alchemist Tycho Brahe into an eminent astronomer. It was the unlocking of the mysteries of new stars that has shown us" the key to the evolution 01 the universe, and converted the chaos of astronomical fact into a- cosmic sys-

tern —a key at present handled and tossed about,' by astronomers, but as yet they have not tried to fit it into its wards; thev have not opened the door and looked'Upon this solution of many or Nature’s deepest- mysteries. It is a melancholy fact how tlio lack of physical training causes astronomers to misread spectra. Here is a case where physical reasoning told the veiy character of the actual phenomena that must produce just such spectra. Yet astronomers cannot read it aright, although they have seen it scores of times. Could anything be more conclusive as to the cause of new stars? Dead suns are admitted to exist- in myriads. Grazing impacts are admitted to be more probable- than direct impacts. Physical reasoning tells us that a graze must produce a third body I’l.u must be -an explosion, while on the other hand astronomers talk of stellar explosions as having certainly occurred. Rotating dead suns with fiery scars must send their searchlight around the heavens and be variable stars. _ Variable stars must be, for some time, in pairs. Astronomical research shows that they are so. They must be sometimes surrounded by luminous cosmicdust. Research shows that they are so surrounded. This should be brghtest at minimum, and it is so. The third body should show a- series of complex spectra of a peculiar type- and new stars show all the characteristics that physical reasoning tells us they should. So' much for this fragment of this theory of cosmic evolution. We have not done with our three bodies yet. For convenience I Have called the two dead suns “Flint” and "Steel,” and the exploding mass “Cosmic Spark.” Remember this cosmic spark may be ten million times the mass of the earth. Spectrum analysis suggests it often is even a greater mass, and reasoning from star clusters tells that sometimes it- may be many times greater than that. AVe left Flint and Steel flying from the Cosmic Spark, Cosmic Spark exploding, and its gas becoming a huge shell, which is called a planetary nebula. It expands so fast as to enclose Flint and Steel inside its vast gas globe. DOUBLE STARS. Cosmic bodies get up most- of their speed when nearing each other. A comet falling from the earth on to the sun would get up more than ten times as much, speed as one would acquire in falling from a fixed star to the earth. In the same way bodies lose speed in leaving each other, so the headlong rush of a graze will be mainly over in a day. But in the case of Flint and Steel they not only pull one another, but Cosmic Spart (the third body) pulls them as well, so their final speed is less than before they began to fall together. Sometimes they will never get entirely away from each other’s attraction. They will be wedded into double stars. There are thousands and thousands of stars that, to the naked eye, look just like ordinary stars, that, when seen through a good telescope, are found to be double. Examining these stars with a telescope armed with a prism, the hydrogen and other bands are seen to be displaced and to differ in such a- way as to tell us that double stars are revolving around each other. They constitute- a solar system with two suns often differently colored. Life on a- planet with a pair of suns would be full of variety. The eccentricities of the most varied seasons would be nothing to it. But at present we are not interested in the speculative poetry of science. AYe are in the realm of the real. . Now we are interested in how stars came, to bo wedded into inseparable pairs. In some- cases doubtless there were two nuclei formed in the star mist that gave- birth to the system. Three- stars passing" near one another may sometimes result In wedding two of them into a double star. But the characteristics of these twin suns suggest that most of them have been wedded by a partial impact. The mutual pull of the escaping scarred suns that wo have agreed to call Flint and Steel, aided by the pull of the- spark struck off, may prevent them escaping each other’s * influence, and their strong mutual attractions would make them an inseparable pair. But the- law of orbital motion says that they must periodically pass through the place of their fiery encounter, and strike off cosmic sparks as the effect of their tremendous blows, a fight to a finish instead of a wedding. This fa-ct was pointed out by Proctor, but Proctor, in coming to this conclusion, did not for all the agencies any more than Lord Kelvin did in coming to the conclusion of the dissipation of energy and cosmic death. The affinities of Flint and Steel were not alone sufficient to wed .them. It needed the additional attraction of their mutual offspring, Cosmic' Spark, to render them inseparable. But the exploding star, Cosmic Smirk, lias been literally blown to atoms by the heat of the impact, and long before its parents commence returning to give one another their second blow, the explosively hot central body, Cosmic Spark, has become a- vast planetary nebulae, reaching outside the orbit of tli-e two scarred suns. Hence, the third body. Cosmic Spark, no longer attracts them towards the centre. There is only left their mutual pull, and this will not suffice to bring them near each other. Millions on -millions of miles will separate them at their nearest approach. So they never strike again, but, by keeping at respectful distance, remain an inseparable pair. There are many other agen_ ces at work modifying their oubitsy which are, described in former papers. But this agency alone will be sufficient to explain away Proctor’s difficulty.