The Pacific commercial advertiser. [volume] (Honolulu, Hawaiian Islands) 1885-1921, 1900-06-23
MYSTERIES OF THE MOON.
Interesting Observations by Prof.
Pickering Of Harvard.


Pickering Of Harvard.
In a broad, fiat expanse on the moons
northern hemisphere. known to astro-
nOrIers as the Mare Serenitatis, there
Is whitish spot some four miles in
diameter to which the name of Lime
has been given. II has been assidu-
ously watched for many years, because
about 1866 something occurred which
caused a wonderful change in its APP
pearance. Before 1t looked like a crater
but little elevated above the plain and
its throat filed with black shadow.
Suddenly. instead of a crater, it APP
peared as white spot. Later on
dark center showed i'm the spot, as if
the missing crater had yawned again
beneath it's mysterious covering. But
no further change occurred, and as
more than thirty years have since pass
ed without any alteration in the aspect
of Lime some astronomers have begun
TO question whether the observers of
a quarter Of a century ago did not make
a mistake.
Now Prof. Pickering rescues Linnes
reputation as genuine marvel but at
the same time increases the mystery.
Watching it during the eclipse, when
the shadow of the earth passed like a
cooling cloud across the face of the
moon he found by careful measure
ments that the size of the white spot
surrounding Lime increased while
buried in the shadow, the amount Of
the expansion in the diameter of the
spot being about one-sixth of a mile.
AS the eclipse passed off il began to
contract again.
But this is not all. Measurements of
the enigmatical spot made when there
was no eclipse showed that it under
goes a similar but much more extensive
fluctuation in consequence of the varia-
ton in the intensity Of the sunlight fall
ing upon IL i'm the course of the lunar
day. a day upon the moon is equal to
about fourteen of our days-that is to
say, nearly two weeks elapse between
sunrise and sunset at any point on the
face of the moop. Measurements of
Lime made two days after the sun has
risen upon it give it diameter of near
ly FIVE miles. Measured after it has
been exposed eight days To the un-
clOuded sun its diameter is less than
two miles and a half. During the long
lunar afternoon, as the sun gradually
sinks and the fierceness of its heat be-
comes little tempered, Lime begins
to increase again in diameter, and
when the sun gets near the horizon
. the wonderful spot is seen to have al
most regained the magnitude that it
had just after emerging from the lunar
J night.
These changes suggest frost spread
I ing in the shadow and receding in the
sunshine, or cloud alternately grow
). ing and contracting under similar in
$ fiuences. The fact discovered by Prof
= Pickering that even the shadow of the
= earth falling for a short time upon the
= spot causes it TO expand to a measure
I BILE degree shows how sensitive it is tC
4 alterations of temperature.
Z But frost or a cloud upon the moor
| pre-supposes an atmosphere and va
z pors there. They certainly must bt
g widely different from such things upor
c the earth, but If they are abundan
I enough to cause motions and changes
= visible to our eyes. their presence ma!
o possibly indicate the existence of ye
{ more interesting things in the luna
= world.
v 1t should be added-because the fact
: while at present increasing the mys
terry. may in the end aid in solving it
d, that changes like those witnessed il
:, Lime do not appear to affect most o
the other well-known markings on tn
moon. AZ the time of his eclipse oh
servations Prof. Pickering CAREFUL
: watched three or four remarkabl
- localities on the lunar surface, wher
- craters yawn or fiat plains lie extended
!. but not the slightest alteration was oh
= served i'm their forms or appearance
during the time that Lime was eS
panding under the chilling effect of tn
!, earths shadow and then shrinkin
- again as the untempered blaze of tn
- sun fell upon 1t.
There is, however, at least one othC
locality on the moon where curioJ
he changes of similar origin have been d.
~ tected-the ring-shaped plain Gale
H. Plato. This is also in the northern IL
Is mar hemisphere. about 500 miles fro
or Lime. 1t is astonishingly regular
nd outline, about sixty miles in diamete
es very fat and completely encircled wit