Evening star., 1935-02-14
STARS, MEN AND ATOMS
Notebook of Science Progress in Field,
Laboratory and Study.
BY THOMAS r. HENRY.

A disturbing variation as great as
six miles second in the speed OF
light-a range from 299,770 to 299, 780
kilometers-has astronomers puzzled.
The results of nearly 5000 separate
determinations made in a vacuum
through a mile-long pipe have just
been announced by DR.. F. G. Pease
of the Carnegie Institution OF Wash
! ington, who was associated with the
late Prof. Albert A. Nicholson in this
supposedly final effort to fix the value
of one of the fundamental constants
of creation.
For practical purposes the speed OF
light, by far the greatest speed Of
which man has any conception, Is
usually stated in a round number
186, 900 miles a second. But for finer
calculations land much of the current
speculation on the nature and struc-
ture of the universe is predicated quite
precisely on this constanD an exact
figure is essential.
The late Prof. Nicholson started the
project, with grant from the Car
negie Institution of Washington, in
1926. The mile course was measured
and remeaSured with extreme exacti-
tude by engineers of the Coast and
Geodetic Survey. The possible error
was less than one part in 10 million.
1t was spoken of as "the most accu-
rately measured mile in the world." +"
The evacuated pipe line was set up
with a system of rotating mirrors and
measurements started.
During 1881 493 separate determi-
nations were made. The mean value
obtained was 299,770 kilometers a
second. During the first few months
of 1882 there we're 753 determine
tions. The mean value was 299, ,780.
Then 742 determinations in the latter
part of 1882 gave mean value Of
299,77l. To add to the confusion,
897 determinations in 1888 gave a
mean of 299,775. The mean Of all
was 299,774, which probably will re-
main the accepted value until the
reasons for the variations can be
found and allowance made for them.
The clue now being followed Is
that the larger values tend to cluster
about the early months of each year
and the variations can be Arranged
in a time curve. There is some
likelihood, DR.. Pease believes, that
a tidal effect is involved and the
solution of the problem may bring
the astronomers into contact with
some hitherto unsuspected law OF
nature. They have established to
their own satisfaction that the diff
ficulty cannot be found in their own
| instruments, and the Coast and Geo.
detic Survey is certain that the mile
is as near perfect as mile can be
measured.
4 4 X y
The astronomers do not believe
that the speed Of light, per Sc,
actually varies.
It Is one Of the few constants in
highly chaotic cosmos which now
is considered as fundamental. If 1t Is
not a fixed quantity the problem OF
reducing to order the vast reaches
of space, where distance is stated
in terms of the vastnesses traversed
by light in a year, becomes far more
complicated than hitherto has been
supposed. Astronomers now talk in
terms of millions of light years. A
million light years is about the dis
tance of the nearest Of the nebulae.
or systems of stars existing beyond
the reaches of our own galaxy. So
even O variation Of five miles . second
would lead to Q very considerable
error, indeed, when multiplied by
5000, ,000, ,000, 900 - the number OF
seconds separating US from our near
est galactic neighbor. Even for dis