The Republican. [volume] (Oakland, Md.) 1877-current, 1892-08-05
ALEcTURE ON MOONS.
AZ Least Twenty In the solar system
some Better Than Ours.

some Better Than Ours.
The moons of Mars were discovered a
few years ago through the telescope Of
the naval observatory at Washington
by Prof Asaph. He will be actively in
terested in the observations of that
planet and its new-found satellites
which will be made in August next by
astronomers all over the world. Since
the discovery of the moons in 1887 this
is the hrst opportunity afforded for ex-
amining them, inasmuch as they are so
small as to be perceptible only at close
range. Once in every fifteen years
Mars reaches its nearest point to the
earth. Eight weeks hence it will be
within $4,000, 900 miles of us, whereas
its greatest distance is 14l 900, 900 miles.
Great interest attaches to the matter
because this sister world is so much
like our own in respect to its climate
and other conditions that it may reason
ably be supposed to be inhabited.
There are at least twenty moons in
the solar system Saturn alone has
eight, the biggest of them, Titan, being
nearly twice the size of our moon, and
Jupiter possesses four ranging in di-
mansions upward from Europa, just
about as large as tn e orb of terrestrial
night to Ganymede, greatest Of all
known moons, with a diameter Of 8, $50
miles, whereas the moon belonging to
this world is only 2, 1850 miles through.
Though our moon is supposed to be
dead and cold, similar con ditions are
not assumed to govern all the satellites
Of the sister planets. Some of those
pertaining to Jupiter are believed to
emit light of their own, showing that
they are still hot II owever, astrono-
mers are usually eager to find evidence
of life on other spher es, even discover
ing on the earth's att endant orb appar-
ent traces of mighty w orl>s of engineer
ing artifice-the imagined creations of
races of beings long extinct-such as
the stupendous bridge that appears to
span a crater Of tn e moon volcano called
Eudoxus.
Eclipses are ev cry day affairs on Jup-
tier Three of ! Is satellites are collapsed
at every revolution of that mighty
globe, so that a spectator there might
witness during the Jovian year $500
eclipses of moons and bout the same
number of echpses of the sun by moons
One of Saturn's mos ns, called Mimas
about half the size of the earth's satel-
lite, is so close to the planet in it's cir
cling that it seems to cross the face of
the latter at an asst onishing rate of
speed. OF the seven 9th ers, Titan has
80 ~ Ia 1
miles, Rhea | 200 miles, Dione and
Thetys each 800 miles, while Enceladus
and Hyperian are very little fellows
Several of them in the sky together
with the flaming rim of star dust
stretched athwart the heavens, must
make gorgeous spect acle by night on
the Saturnian sphere. Through the
telescope it is very int resting to watch
the shadows thrown u pom Jupiter by
that giant planets IN oons, observation
Of the eclipses of viii ch furnished the
irst data for estimatin the velocity Of
light Uranus has four little moons
Ariel, UmbrieL Titania and Oberon--
which, funnily enough, rise in the north
and set in the south. A single diminu-
tive one, belonging to Neptune, ira
verses the sky from southwest to north
east Neither Murcury nor Venus has
any satellites.
But the most interesting Of all moons
are the two that attend Mars, each
about sixty miles in diameter. That
planet is just one-half the size Of the
earth; its surface is divided into con-
tinents and seas, having as much land
as 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 APP
pears to rise in the west and set in the
east, while the other, really circling in
the same direction at a speed compare
lively 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.
One of the most remarkable guesses
on record was made by Dean Swift,
who, a century before the moons of
Mars were discovered, made Gulliver
say of the astronomers Of Laputa:
hcy nave iOunu TWO Sdleilltes "nlcn
revolve about Mars, whereof the inner
most is distant from the planet exactly
three diameters of the planet; the for
mer revolves in the space Of ten hours
and the latter in twenty-one and one
half hours" In fact the inner moon is
10000 miles from Mars, whereas-the
diameter of the planet being 1000 miles
-Gulliver's estimate would place IL at
$4,000 miles For the outer moon he
gives 1000 miles for the distance, which
is really $4,000 miles The time of revo-
luton for the inner moon is actually
seven and one-half hours and for the
outer one thirty hours. PRO-. Hall has
named these moons Deimos ard Phobes,
after the attendants of the god Mars,
who are mentioned in Homer's "Iliad."