392
DOC.
42
SPECIAL AND GENERAL RELATIVITY
APPENDIX FOUR
The
Structure
of
Space
According
to
the
General
Theory
of
Relativity
[102]
[Supplementary
to section 32]
Since
the
publication
of the first edition of
this
little
book,
our
knowledge
about the
structure
of
space
in
the
large
("cosmo-
logical
problem")
has
had
an
important
development,
which
ought to
be mentioned
even
in
a popular presentation
of the
subject.
My original
considerations
on
the
subject
were
based
on
two hypotheses:
1.
There
exists
an
average
density
of
matter
in the
whole
of
space
which
is everywhere
the
same
and different
from
zero.
2.
The
magnitude
("radius") of
space
is independent
of
time.
Both these
hypotheses proved to
be
consistent,
according to
the
general theory
of
relativity,
but
only
after
a hypothetical
term
was
added
to
the field
equations,
a
term
which
was
not
required by
the
theory
as
such
nor
did it
seem
natural from
a
theoretical
point
of
view
("cosmological term
of
the field
equa-
tions").
[103]
152