Evening star. [volume] (Washington, D.C.) 1854-1972, 1900-05-12
MYSTERIES OF THE MOON
INTERESTING OBSERVATIONS BY
PROF. PICKERING OF HARVARD.
An Enigmatical Spot Which Has Long
Been Under Close scrutiny - Some
Dn, Our Satellite May Astonish Us.


In broad. fiat expanSe on the moon
mort bern hemisphere, known to aStrono-
merS as the. Mare Serenitatis, there Is
whitish spot some four miles in diameter
to which the name of Lime has been gwen
II has been assiduously watched for many
years because about 1866 something &C.
CURED which caused a wonderful change In
its appearance. Before it looked like a
crater but little elevated above the PLAIN
and its throat filed with black shadow
Suddenly. instead of a crater 1t appeared
as a white spot Later on dark center
showed in the spot as if the missing crater
had yawned again beneath its mysterious
covering But no further change occurred
and as more than thirty years have since
paced without any alteration In the aspect
of Lime some astronomers nave begun u
question whether the observers OF quar-
ter of ID century ago did not make mis-
take.
Now Prof. Pickering rescues Linne's rep
utation as a genuine marvel but at the
same time increases the mystery Watch-
ing 1t during the eclipse, when the shadow
of the earth passed like cooling cloud
across the face of the moon. he found by
Careful measurements 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 mile. AS the
eclipse passed off it began to contract
again.
But this is not all. Measurements of the
eniematicaI spot made when there was no
eclipse showed that ii undergoes a similar
but much more extensive fuctuaton III
consequence of the variation in the inten-
sity of the sunlight falling upon it in 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 e!apse
between sunrise and sunset at any point
on the face of the moon. Measurements
OF I.inne made two days after the sun mas
~ n-a, of nc.
five miles. Measured after II has been ex-
posed eight: days to the unc!ouded sun It's
diameter is less than two miles and a half
During the long lunar afternoon. as the
sun gradually sinks and the ferceness of
its heat becomes a little tempered Lime
begins To increase again in diameter. ana
when the sun gets near the horizon the
wonderful spot is seen to have almost re-
gained the magnitude that it had just AFTER
emerging from the lunar night.
These changes suggest frost spreading
In the shadow and receding In the sun
shine, or a cloud alternately growing ana
contracting under similar influences. The
fact discovered by Prof Pickering that
even the shadow of the earth falling for a
short time upon the spot causes II to eX-
pand to a measurable degree shows how
sensitive 1t Is to alterations of temperature.
But frost or cloud upon the moon pre-
supposes an atmosphere and vapors there
They certainly must be widely different
from such things upon the earth, but If
they are abundant enough to cause motions
and changes visible TO our eyes, their pres
ence may possibly Indicate the existence OF
yet more interesting things in the lunar
world
1t should be added-because the fact.
whila at present increasing the mystery.
may in the end aid in solving ft-that
changes like those witnessed in Lime do
not appear to affect most of the other we'll
known markings on the moon. At the time
of his eclipse observations Prof. Pickering
carefully watched three or four remarka BILE
localities on the lunar surface. where era
tiers yawn or fiat plains lie extended, but
not the slightest alteration was observed
in their forms or appearance during the
time that Lime was expanding under the
chilling effect of the sarths shadow and
then shrinking again the untempered
blaze of the sun fell upon 1t.
There is however. at least one other
locality on the moon where curious changes
OF similar origin have been detected-the
ring-shapsd plain called Plato. This Is
also in the northern lunar hemisphere,
about 900 miles from Lime. 1t is aston
tshingiy regular in outline. about sixty
miles i'll diameter Very fiat ard completely
encircl"d with lofty, steep and sharp-peak ed
mountaius-as fine valley for nation OF
h-FmItS to inhabit could Well be I'M
agine,l. A few thousand Boer ritiemen sta
toned on the kopjes of Plato could make
1t safe from invasion against the entire
lunar world. In this singular mountain
rinEed valley 1t has been noticed that the
rising sun, just peering above the surround
ing peaks looks down upon vast whitish
gray rXpanse, filling the whole OF the I'M
ns!.se interior. But az the solar orb swings
clear vi the mountain tops and the shad-
ows If the pinnacles and ridges become
shorter upon the plain beneath the gray
color first brightens and then rapidly fades
over all the surface Of the valley until
at lunar noon Plato has turned almost
black, while at the same time its inclosins
mountains of chalky wilderness are ablaze
with thu sunshine.
These appearances. taken in connection
with the remarkable phenomena reported
by Prof. Pickering. indicate that there are
certain places on the moon where the con-
trast be; ween daylight and darkness or
between heat and cold manifests peculiar
effects. and IN those places the search for
further discoveries should be pushed. Some
day our silent satellite may astonish US
viii revelations of greater human interest
than any that PARKWAY Mars can offer.