THE UNIVERSE AND MATTER — LOUIS-JARAY 135 



for distant galaxies in no way related to our galaxy, any law whatso- 

 ever which governs the life of all galaxies by comparison with our own. 



One other hypothesis of astrophysicists seeks to solve the contradic- 

 tion between the finite and the infinite; they call it the "curved uni- 

 verse." Curvature, sphericity, is to be the law of matter. The 

 universe is shaped like an immense sphere, an enormous bubble; all 

 radiation follows a curve; light coming to us from distant galaxies is 

 bent. In consequence, light from a star ought to arrive at the earth 

 from two opposite sides, from one side by the direct curve and from 

 the other by making the complete circuit of the sphere. Let us await 

 experimental proof that the propagation of radiation, energy, or 

 light is not in a straight line but a curved path. 



Without letting ourselves be carried away by imagination, let us 

 realize that the tests of the past 30 years have led physicists to modify 

 entirely their conceptions of the world, of light, of matter, of energy, 

 of the universe. The infinitely great and the infinitely small seem 

 immeasurable; they are not of the same order of magnitude as man. 

 The mind asks, at each stage, whether these discoveries are not only 

 symbols, constructions of the mind, whether they correspond to some- 

 thing entirely objective. At every moment one is tempted to say: 

 "This happens as if"; but one dares only say: "This happens thus." 

 At any rate, the new physics is the creator of mysteries. These are 

 mysteries: The microscopic and the macroscopic, the indeterminism, 

 the discontinuity, elements which change from one substance into 

 another with the disappearance of part of their mass, the conversion of 

 matter into energy and energy into matter. In place of the older, 

 rigid mechanics, with the unalterable conservation of matter, with 

 all motion determinate, with elements whose positions and velocities 

 were known repeating themselves in "the form and motion" of Des- 

 cartes, there is substituted anew physics which is directed by new views 

 concerning the unity of matter and light, the principle of equivalence 

 including the conversion of energy into matter and matter into energy, 

 the introduction of discontinuity and indeterminism by wave ma- 

 chanics. These views completely change our conceptions of the 

 exterior world and of the universe. 



