DOC.
30
FOUNDATION OF GENERAL RELATIVITY
199
concave
towards the
origin)
is
given
in
sufficient
approxi
mation
by
+
00
B
1
J

oo
1
while
(73)
and
(70) give
gewh
drh rheb
segh
Carrying
out the
calculation,
this
gives
B
2
a
«M
2ttA'
.
(74)
X
A
X
Fig.
8.
[36]
According
to this,
a
ray
of
light
going
past
the
sun
under
goes
a
deflexion
of
1.7";
and
a
ray
going
past
the
planet
Jupiter
a
deflexion of
about
.02".
If
we
calculate the
gravitational
field to
a
higher
degree
of
approximation,
and likewise
with
corresponding accuracy
the orbital motion
of
a
material
point
of
relatively infinitely
small
mass,
we
find
a
deviation of
the
following
kind
from
the
KeplerNewton
laws of
planetary
motion.
The
orbital
ellipse
of
a
planet undergoes
a
slow
rotation,
in the direction
of motion, of amount
€
=
247T3
a
2
TV(1

e2)
(75)