Beyond the Milky Way^*

Abstract

OUR earth is one of a system of nine planets which, with millions of smaller bodies—asteroids, comets, and meteors circle round the sun; our sun is one of a system of millions of stars which circle about one another; this star-system is one of millions of star-systems—and here, so far as we know, the sequence ends abruptly. These star-systems are the biggest objects known to science; there is nothing beyond them except the great universe itself. They form the largest subdivision of the universe, and it is from this circumstance that they derive their special importance to science.