There is no more difficult problem in astronomy than
that of disentangling the effects of the solar motion from those of
the motions of the other stars. But the problem, difficult as it is,
has been solved, and upon its solution depends our knowledge of the
speed and direction of the movement of the solar system through space,
for of course the sun carries its planets with it. One element of the
solution is found in the fact that, as a result of perspective, the
stars toward which we are going appear to move apart toward all points
of the compass, while those behind appear to close up together. Then
the spectroscopic principle already mentioned is invoked for studying
the shift of the lines, which is toward the violet in the stars ahead
of us and toward the red in those that we are leaving behind. Of
course the effects of the independent motions of the stars must be
carefully excluded. The result of the studies devoted to this subject
is to show that we are traveling at a speed of twelve to fifteen miles
per second in a northerly direction, toward the border of the
constellations Hercules and Lyra. A curious fact is that the more
recent estimates show that the direction is not very much out of a
straight line drawn from the sun to the star Vega, one of the most
magnificent suns in the heavens.
Pages:
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56