Evening star. [volume] (Washington, D.C.) 1854-1972, 1892-06-25

| over the world. Since
the discovery Of the moons in 1887 this is the
first opportunity afforded for examining them,
inasmuch as they are 30 small as to be only per-
ceptible at close range.
When the lover swears by the earth's "incon-
slant" satellite it never occurs to him to con-
slider that there are at least twenty moons in the
solar system. Saturn alone has eight, the big
gest OF them, Titan" being nearly twice the
size OF our moon, and Jupiter possesses four,
ranging in dimensions upward from Europa"
Just about as large as the orb Of terrestrial
| night, to "Ganymede." greatest Of all known
moons. The latter has diameter Of $3.50
miles, whereas the moon belonging to this world
| Is only 2, 160 miles through.
| SATELLITES OF THE SISTER PLANETS
Though our moon is supposed to be dead and
| cold, similar conditions are not assumed to
govern all the satellites of the sister planets
Some OF those pertaining to Jupiter are be-
| lleved to emit light of their own showing that
| they are still hot However, astronomers are
| usually eager to find evidence Of life on other
spheres, even discovering on the earth's at
tendant orb apparent traces of mighty works of
| engineering artifce-the imagined creations of
races OF beings long extinct-such as the stu
pendous bridge that appears to span a crater Of
the moon volcano called "Eudoxus."
EcLIPsEs.
Eclipses are everyday affairs on Jupiter,
Three of its satellites are eclipsed at every rev.
olution of that mighty globe, so that a spec
tator there might witness during the ioyian
year 500 eclipses of moons and about the same
number of eclipses Of the sun bv moons I'm
oer saeh conditions one would become accus-
toned to phenomenon which occasionally ap-
pals the terrestrial observer The Hindoos.
when they see the black disk of the moon ad-
vanclng over the sun, believe that the latter Is
being swallowed BY a dragon. Then they
beat gongs and scream until the frightened
monster disSorges his fiery mouthful.
sArURN's MOONS.
One of Saturn's moons, called "Mimas. ~
about half the size of the earth satellite, is 50
close to the planet in its circling that it seems
to cross the face Of the latter at an astonishing
has diameter Of $500 miles, "Iapetus'' / 500
miles, ''Rhea" 1 200 miles, "Dione" and
'Iethys" each 500 miles. while ''Enceladus''
and Hyperion" are very little fellows. Several
OF them in the sky together. with the flaming
ring OF stardust stretched athwart the heavens,
must make gorgeous spectacle by night on the
saturnian sphere. Through the telescope it is
very interesting to watch the shadows thrown
upon Jupiter by that giant planets moons OBJ
servation of the eclipses of which furnished the
first data for estimating the velocity of light.
THE DIMINUTIvE MOONS OF URANUS.
Uranus has four little moons-"Ariel," "Um-
briel, "Titania" and "Oberon''-which. fun
nily enough, rise in the north and set in the
south. A single diminutive one belonging to
Neptune traverses the sky from southwest to
northeast. Neither Mercury nor Venus has INV
satellite. But the most interesting Of all moons
are the two that attend Mars, each about sixty
miles In diameter. That planet is lust one-haif
the size OF the earth its surface is divided into
continents and seas, having as much land US
water. 1t has an atmosphere, clouds frequently
concealing Its face, and its seasons are about
the same as here, though the winters are colder
Because one of its moons travels around it three
times as fast as Mars itself turns, it appears to
rise In the west and set in the east, while the
other, really circling in the same direction at a
speed comparatively slow, rises in the east and
sets in the west. Thus both moons are seen in
the heavens at the same time, going opposite
ways.
The most remarkable guess on record was
made by Dean Swift, who a century before the
moons OF Mars were discovered, made CULVER
say OF the astronomers Of Laputa: They have
found two satellites which revolye about Mars
whereof the innermOst is distant from the
planet exactly three diameters of the planet:
the former revolves in the space of 10 hours and
the latter in II u hours" In fact. the inner
moon il 10, 900 miles from Mars, whereas
diameter Of the planet being 1000 miles
Gulliver's estimate would place it at $4,000
miles. For the outer moon he gives 20 600
miles for the distance, which is really $4,000
miles. The time Of revolution for the inner
moon Is actually ~ hours, and for the outer
one 80 hours. Prof. Hall has named these
moons 'Deimos' and "Phobos," after the at
tendants of the god Mars, who are mentioned
in Homer's Iliad.
THE ASTEROIDS.
Hundreds Of minor planets belonging to the
solar system, which are only big enough for
moons though not such, have been discovered
during the present century. They are called
asteroids" and the three largest Of them are
"Vesta, !" "Ceres" and "Pallas.p Many of them
are only of about the bigness of a good sized
farm. Life upon one Of them, owing to the fee
bleness OF gravity, would seemingly be attended
with difficulties. One ingenious romancer has
described an imaginary journey through SPACE,
in the course Of which he landed upon a small
asteroid, finding it occupied by single giant.
The latter. being displeased with some remarks
made by his visitor, kicked him off into space
go far that he fell within the attraction Of an
other sphere.
UNDISCOVERED MOONS.
To solar planets yet undiscovered moons may
belong-for example. to the mysterious ''big
dark sphere" beyond most distant Neptune
which some astronomers assert the existence of.
A similar hypothetical world, alleged to have
its orbit inside that Of Mercury, is vulcan"
Science has not accepted the latter, though two
ODseTVers, oWlIt ana watson, working indie
pendentiy in Colorado few years ago stimuli
taneously declared that they saw it. Watson
was SO confident of his find that he built a
tunnel in the side of a hill pointing toward the
supposed new star, with a reflector at the
bottom, thinking to the object better.
From the bottom of a WELL of course, one can
perceive the stars by day with the naked eve.
But this enthusiast died without proving his
belief. The existence Of vulcan and the,
''trans-Neptunian" sphere has been inferred
from otherwise unaccountable perturbations Of
the known orbs Of the solar system.
CAPTURING COMETS.
Many comets which would otherwise pass BY
into the realms Of space beyond are captured
by the great outer planets-Jupiter, Saturn,
Uranus and Neptune-and forced to Join the
family Of the sun, becoming what are called
periodic" comets. Those four vast globes are
all more or less liquid and gaseous, 90 that
there cannot be any life on them. OF Neptune
and Uranus almost nothing is known, because
they are 20 far away, but the two giant orbs,
Saturn and Jupiter, are smaller suns not yet
quite extinguished. Ages hence they win cool
down and be Transformed doubtless into inhab-
tied worlds. There may be life on Venus anc
Mercury, though it must be too warm for COM
fort, inasmuch as Venus is one-third nearer the
sun than the earth is, and Mercury 10 less than
half as far away.
SIZES AND DISTANCES.
pretty fair notion Of sizes and distances in