February', 1931 



EVOLUTION 



Page three 



The Range of the Universe 



By HARLOW SHAPLEY 



' I 'HE galaxy-hunting astronomer may appear to be a rare 

 spirit, blessed with the privilege of associating always 

 with grand affairs — big stars, long distances, great spaces. But 

 he does not greatly delude himself. His is also a world of 

 littleness. His first sidereal measurement takes him out of touch 

 with dimensions galactic to the minutest of things. To measure 

 he must see. To see he must have light. To have light he must 

 be in contact with the infinitesimals of the sub-microscopic 

 world. 



There is no avoiding electrons, whose diameters are a mil- 

 lionth of a millionth of millionth of a mile, when we measure 

 the galactic system, whose diameter is a million, million, mil- 

 lion miles. We need to consider the behavior of the individual 

 radiating mechanism, consisting of one atom, when we analyse 

 the behavior of an individual radiating star composed of more 

 than 1 ,000,000,000,000,000,000,000 , 000 , 000 , 000 , 000 , 000 , - 

 000,000,000,000,000,000,000 atoms. Stars and atoms must be 

 taken together, light waves and light years, electron motions 

 and drifts of galaxies. 



A survey of material systems will therefore remain rightly 

 in the astronomer's field when it includes clusters in which 

 the units are stars, and atoms in which the units are corpus- 

 cular electrons and protons. The astronomer continually goes to 

 the physical laboratory for guidance in theory and for experi- 

 mental facts; the physicist frequently goes to the stars for in- 

 spiration and for data. 



It is our ambition to start at the bottom and work our way 

 up in the world. We shall therefore begin with electrons . . . 



We have no right whatever to maintain doggedly that we 

 have reached the ultimate in infinitesimal material systems 

 when we deal with these familiar material units. Experience 

 should quickly teach us how unsafe such an assumption would 

 be. A few decades ago not even the atom would have been ad- 

 mitted to the society of systems. Atoms were the little, hard, 

 ultimate chunks of matter, indivisable by grace of name and ex- 

 periment and scientific dogma. But atoms are no longer listed 

 as ultimates, they are now among the best of material systems; 

 and even their unit components cannot maintain the former 

 atomic role of being the indivisable stones from which the ma- 

 terial universe is built. Experience certainly recommends cau- 

 tion in asserting any lower limit in the organization of the 

 microcosmos. 



On the other hand, since we can know of electrons and 

 protons and the units of radiation only by using electrons and 

 protons and units of radiation in our technique of measuring 

 and comprehending, it may be that we have already got near 

 the bottom of measurable units and systems of units. Light 

 waves and electrons can be rather handily used to measure 

 ^ those bodies and systems of bodies in the material world th.it 

 are larger than electrons and light waves. In the relatively 

 coarse-grained world in which we are to work, they are efficient 



tools. But in the hypothetical sub-electronic world, where there 

 may be systems within systems indefinitely, our coarse-grained 

 tools no longer bring information to our coarse-grained minds. 

 It may be that we are stopped in our explorations downward, 

 not because the limit is reached, but because of our inherent 

 awkwardness. 



To register our conviction that the series of systems extends 

 downward, and that for us its limit is indeterminate, we shall 

 start our list of material systems with an empty dotted line, and 

 give it the class number — 5. The first recognizable systems, 

 therefore, have the number — 4. These small entities may be 

 appropriately given the generic name Corpuscles, and we start 

 out thus: 



— 5 



• — • 4 Corpuscles 



— 3 Atoms 



— 2 Molecules 



— 1 Molecular Systems 



Colloidal and Crystallic Aggregates 



+ 1 Meteoric Associations 



+ 2 Satellitic Systems 



+ 3 Planetary Structures 



+ 4 Double and Multiple Stars 



-'- 5 Galactic Clusters 



+ 6 Globular Clusters 



+ 7 Galaxies 



+ 8 Multiple Galaxies 



+ 9 Supergalaxies 



+ 10 The Metagalaxy 



+ 11 The Cosmoplasma 



+ 12 The LJniverse (Space-Time Complex) 



+ 13 ' 



Let us indulge one idle fancy. Is our inability to get deeper 

 into the minutiae of the microcosmos or, in the other direction, 

 farther into trans-galactic space tied up somehow with our own 

 dimensions? It is a singular fact that electrons, in diameter, 

 are just as much smaller than a man as he is smaller than a 

 supergiant red star, the biggest body he measures. The observer 

 is thus geometrically near the middle of the range. Also, in ma- 

 terial content he is in a middle position. The biggest definitely 

 organized and closely coherent bodies we measure are these 

 giant stars that contain about 10'* corpuscles (electrons and 

 protons) . An average man's body contains 10^' corpuscles — 

 halfway down towards the unit electron.* 



If the observer and interpreter were as large as Betelgeuse 

 might he fail in his survey to reach objects smaller than the 

 meteors and moons, but perhaps go far beyond our metagalactic 

 system in the direction of things extensive? Or if he were of 

 the dimensions of a bacterium, might not the sub-electronic 

 world open up easily, though he fail to comprehend or meas- 

 ure the stars and larger parts of the sidereal universe? 



Excerpts from "Flights from Chaos" bv Harlow Shapley, with per- 

 mission of the author and publisher. Copyright, 1930, by the Mc- 

 Gr,iw-Hiil Book Co., Inc. New York, N. Y. 



*The exponent figures indicate that ten is to be used that many 

 times in multiolving. If the exponent figure is preceded bv a minus 

 sign, ten is to be used that many times in dividing. This device saves 

 writing a 'ong series of ciphers, 10^* meaning I followed by 58 ciphers. 



