Pittsburg dispatch. [volume] (Pittsburg [Pa.]) 1880-1923, 1892-08-07
THE LITTLE MOONS OF MARS.
Their Discovery by = Washington Astron-
omsr-Somsthing About Thsir Con-

Their Discovery by . Washington Astron-
omsr-something About Thsir Con-
dition.
Washington Star.l
The moons of Mars were discovered 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 by astronomers all over
the world. Since the discovery of the
moons in 1887 this Is the first opportunity
afforded for examining them, inasuluch as
they are so small as to be perceptible only
at close range. Once in every 10 years Mars
reaches Its nearest point to the earth.
Eight weeks hence it will be within 35, ,OOO,-
600 miles of us, whereas its greatest dis
tance is 141, 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
reasonably be supposed to be inhabited.
There are at least 20 moons in the solar sys-
tenn. Saturn alone has eight, the biggest of
them, Titan, being nearly twice the size of
ing in dimensions upward from Europa,
Just about as large as the orb of terrestrial
night, to Ganymede, greatest of all known
moons, with diameter of 8, 4S0 miles,
whereas the moon belonging to this world
is only 2,160 miles through.
Though onr moon is supposed to be dead
and cold, similar conditions are not assumed
to govern all the satellites of the sister
planets. Some of these pertaining to
Jupiter are believed to emit lights Of their
own, showing that they are still hot. How
ever, astronomers are usually eager to find
evidence of life on other spheres, even discov-
ering on the earth's attendant orb apparent
traces of mighty works of engineering arti-
fce-the imagined certain creation of races
being long extinct-such as the stupendous
bridge that appears to span q crater of the
moon volcano called Eudoxua Eclipses
are everyday affairs on Jupiter. Three of
its satellites are eclipsed at every revolu-
tion of that mighty globe, SO that specta-
tor there might witness during the Joyian
year 4, 500 eclipses of moons and about the
same number Of the sun by moons.
One of Saturn's moons, called Mimas,
about half the size of the earth's satellite,
is so close to the planet in its circling that
it seems to cross the face of the latter at an
astonishing rate of speed. OF the seven
miles, Iapetus I, 800 miles, Rhea ], 200 miles,
Dione and Thetys each 500 miles, while
Enceladus and Hyperion are very little fell
lows. Several of them in the sky together,
with the flaming ring of star dust stretched
athwart the heavens, must make a gorgeous
spectacle by night on the Saturnian
sphere. Through the telescope it is very
interesting to watch the shawdows thrown
upon Jupiter by that giant planets moons,
observation of .the eclipses of which fur
nished the first data for estimating 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
diminutive one, belonging to Neptune,
traverses the sky from southwest to north
east. Neither Mercury nor Venus hos any
satellites. But the most interesting OF all
moons are the two. that attend Mars. each
about 60 miles in diameter. That planet is
just one-half the size of the earth; its surface
is divided into continents and seas, having
as much land as water; it las an atmos-
phere, clouds frequently concealing its face,
and its seasons are about the same as here,
though the waters are colder