Now we can carry on our computation as we supposed the farmer to
measure the extent of his wheat-field. Let us suppose that there
are 125,000,000 stars in the heavens. This is an exceedingly rough
estimate, but let us make the supposition for the time being.
Accepting the view that they are nearly equally scattered
throughout space, it will follow that they must be contained
within a volume equal to 125,000,000 times the sphere we have
taken as our unit. We find the distance of the surface of this
sphere by extracting the cube root of this number, which gives us
500. We may, therefore, say, as the result of a very rough
estimate, that the number of stars we have supposed would be
contained within a distance found by multiplying 400,000 times the
distance of the sun by 500; that is, that they are contained
within a region whose boundary is 200,000,000 times the distance
of the sun. This is a distance through which light would travel in
about 3300 years.
It is not impossible that the number of stars is much greater than
that we have supposed. Let us grant that there are eight times as
many, or 1,000,000,000. Then we should have to extend the boundary
of our universe twice as far, carrying it to a distance which
light would require 6600 years to travel.
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