صفحة 177 من 212

It follows from what has been said, that closed spaces without

limits are conceivable. From amongst these, the spherical space

(and the elliptical) excels in its simplicity, since all points

on it are equivalent. As a result of this discussion, a most

interesting question arises for astronomers and physicists, and

that is whether the universe in which we live is infinite, or

whether it is finite in the manner of the spherical universe. Our

experience is far from being sufficient to enable us to answer

this question. But the general theory of relativity permits of

our answering it with a moderate degree of certainty, and in this

connection the difficulty mentioned in Section XXX finds its

solution.

XXXII.

THE STRUCTURE OF SPACE ACCORDING TO THE GENERAL THEORY OF

RELATIVITY