The Ohio Democrat. (Logan, O. [Ohio]) 1886-1906, 1891-09-19
EARTH VIEWED FROM ITS MOON
About sixteen Times ms Big ms the sun and
blue.


About sixteen Times ms Big ms the sun ana
Blue.
H. is evident that to lunar obscryc,
the disk of earth appears to be equal tc
about sixteen areas of the solar disk.
The solar disk, as seen from earth. is
on an average equal to the lunar disk
seen from the same point. for. in a
solar eclipse, the disk of the moon
covers the sun in total event of that
character, while it fails to cover the sun
In an annular eclipse. Therefore. the
apparent sizes of these bodies must
average about equal in size to u terres-
trial observer. Again, the solar disk
will appear to the lunar observer lust
equal to what it seems to be when seen
from earth, because the distance from
the sun to the moon averages equal to
the distance from the sun to earth.
Furthermore, the diameter of earth is
equal to about four lunar diameters,
and of course the areas of their disks
vary as the square of their radii, and
this makes the terrestrial disk about
equal to sixteen lunar disks. and. of
course, If the lunar disk is equal to the
solar disk at given distance, then the
terrestrial disk will seem to be about
sixteen times as great at the same
distance.
This enormous disk of earth must be
blue in color to the lunar observer, be-
cause earth's atmosphere is blue. and
all things seen through it seem blue.
Even interstellar space seems blue
through this medium, and the unillumi-
mated parts of the moon can not be dis
tinguished from the space that abuts it.
Bright, direct and reflected light is not
affected appreciably by its passage
through our atmosphere therefore,
stars, moonlight and distant illumina-
tions are not noticeably blue from that
cause.
1t may be well to examine sunlight
to see why it is not made blue in transit,
and as the moonlight is sunlight reflect
ed the explanation will do for BOTH and
in fact, for all. To the terrestrial OBJ
server of the sun there is visible an illu-
minated cone, the apex of which is in his
| eye and the base on the solar disk Re
ducing this cone to dimensions that the
mind can grasp, we will adopt scale
of 100000 of miles to the inch and inn
agine or construct a cone ten feet high
whose base is one-half an inch in diam
eter. Now, if the mathematical point
or apex of this cone be blue, five ten.
millionths of one inch thick, which is
the proportion roughly, considering the
atmosphere to be forty miles high, il
will be seen why sunlight so easily
overcomes the color of air. If, how.
ever, we construct cone to illustrate
the view of the earth to lunar OBJ.
server we must, to height of ten feet
have base of two inches diameter
with blue coat on that base one-siX.
tieth of an inch thick "a very thick caro-
is about that thickness). Here the base
of the cone is blue instead of the fine
point, and every ray travels through
the whole thickness of the atmosphere o1
earth twice. The whole terrestrial disl;
covered by its blue envelope is seen al
once, and if, as we know to be true
the air colors distant objects blue to the
observer on earth it must color eartl
blue to lunar eye.
| do not forget that when the eartl
is full" to the moon there may be
white spot or spots where the direc
solar rays are reflected to the moon, bu
that spot can not equal the apparen
area of the solar disk, or rather one-siX
teenth part of the apparent terrestria
disk.
OF course, when the moon is eclipset
| To Nth tho nf ffacf Of fhn 1i1r,o ohc
would be solar eclipse Then the blue
air should be visible around the edge o
earth slightly like that seen about the
moon in some cases of total eclipse anC
known as the corona. AT such times
the aurora should family illuminate tn,
dark side of earth and perhaps slight,
be reflected on the eclipsed satellite.
If we consider aurora borealis and it
data, comparing it and them to nebuli
and comets tails, we must believe tina
earth has on the side opposite the sun
valuable streaming appendage of brigh
luminous effect. Authorities, after dii
fering infinitely in results, now declar
that they are ignorant of the height t.
which this phenomenon reaches Hum
boldt says ten degrees, which mean
any height according to the distance
The same aurora has been seen fror
the polar localities to fourteen degree
north. No one knows their height, br
cause our atmosphere may shut out
great part of distant effect, and moor
light and twilight probably neutraliz
the higher effects of all observers. Tn
only question is: Does the lunar OF
server see tail streaming aftc
earth? And considering the clearnes
that the tails of comets exhibit one hur
dred millions of miles distant and Wis
BILE nebula unknown millions of mile
in space, assert that aurora boreali
should be and is bright and beautiful
trail after our great mothers gloriou
garment,
There are many colored stars an
planets. Mars is red, Venus is white
Many stars are blue; in one group al
are blue.-N. Y. Times.
Thought She Had Been Neglected.
"What an enjoyable copcert that wa
last evening"" said Mrs. T. Party
"Indeed! Did you really like it?
asked Miss Warbler, beaming.