Mineral Point tribune. (Mineral Point, Wis.) 1869-1938, 1891-10-24
EARrA V m.n From MOON.
The Globe Appears sixteen Tunes as Big
the Sui, aud Bloc,

The Globe Appears sixteen Tunes as Big
as the Su", aud Bloc,
II is evident that to lunar observer
the disk of earth appears to be equal
TO about sixteen areas of the solar
disk, SAYS a correspondent of the n. Y.
Times. The solar disk as seen from
the cart is on an average equal TO the
lunar disk seen from the same point.
for in solar eclipse the disk of the
moon covers the sun in a total event
of that character. while il fails to
cover the sun in an annular eclipse.
Therefore, the apparent sizes OF these
bodies must average about equal in
size to terrestrial observer. Again.
the solar disk will appear to the lunar
observer Just 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 the earth. Furthermore,
the diameter of the earth is equal to
about four lunar diameters aud 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 a given distance then the ter
restriuI disk will seem to be about six
teen times as great at the same dis
lance.
This enormous disk of earth must
be blue in color to the lunar observer,
because earth's atmosphere is blue.
and all things seen through it seem
blue Even interslelar space seems
blue through this medium, and the un-
illuminated parts of the moon can not
be distinguished from the space that
abuts it. Bright, direct and reflected
light is not affected appreciably by its
passage through our atmosphere;
therefore, stars moonlight aud distant
Examinations are not noticeably blue
from that cause.
1t NAV be we'll to examine sunlight
to see WHY it is not made blue in tran
Sit aud as the moonlight is sunlight
reflected the explanation will do for
bul anil, iu fact, for all. TO "A ter
rpStriu observer OF the sun there is
visible an illuminated cone, the apex
Of which is in Ms eye aud the base on
the solar disk. Reducing this cone to
dimensions that the mind can grasp,
we will adopt IA scale of 600 600 miles
to the inch and imagine or construct
cone ten feet hign whose base is one
half an inch in diameter. Now. il the
mathematical point or apex of this
cone be blue, five mlliOnths of one
inch thick, which is the promotion
roughly considering the aimns phere
to bp forty miles high. it will be seen
wins sunlight SO easily oycrcompS the
color OF air IT, however. we con-
struct Il cone to Illustrate the view of
earth TO lunar observer. we must 10
a height of ten feet have base of two
inches diameter with blue coat on
thai base one-sixlieth of an inch thick
Ga very thick card is about that thick
ness) Here the base Of the cone is
blue instead of the fine point, and
every ray travels through the whole
thickness of the atmosphere of earth
twice. The whole terrestrial disk COW
cred by its blue envelope is seen nj
once, aud if, as we know to be true,
the air coors distant objects blue to
the observer on earth it must color
earth blue to II lunar eye.
do not forget that when earth is
full" to the moon there may be 4
white spot or spots where the direct
solar rays are reflected to the moon,
but that spot can not equal the appar-
ent area OF the solar disk, or rather
one-sixteenth part OF the apparent ter
restrial disk.
Oh course, when the moon is eclipsed
to earth the effect TO the lunar OBJ
server would be solar eclipse. Then
the blue air should be visible around
The edge of earth slightly like that
seen about the moon in some cases OF
total eclipse aud known as the corona.
At sucu times tie aurora should family
illuminate the dark side of the eartn
aud perhaps slightly be reflected on
the eclipsed satellite.
If we consider aurora bUrealis and
ITS data, comparing it and them to
nebula aud comets tails, we must be-
lleye that earth has on the side oppO-
site the sun veritable streaming APP
pendage of bright, luminous effect.
Authorities, after differing infinitely
IN results, now declare that they are
ignorant of the height to which this
phenomena reaches. Humboldt says
ten degrees which means any height
according to the distance. The same
aurora has been seen from the polar
localities TO Ia degrees north. No one
Knows their height, because our at
mosphere may smut out a great part OF
distant effects, aud moonlight and twi-
hight probably neutralize the higher
effects to all observers. The only
question is Does the lunar observer
see tail streaming after the eartl?
Aud. considering the clearness that
ibe tails of comets exhibit loo 900 600
niles distant and visible nebuia un-
SHOWN millions of miles 10 space, J
assert that aurora bOrralis should be
and is "a bright aud beautiful trail after
2Hl great mothers glorious garment.
ere are many cotored star. and
l.anets. Mars is red, Venus i, white.
dany star, are blue; IN one group all
are blue.