The Helena independent. [volume] (Helena, Mont.) 1875-1943, 1892-09-26
he Great Discovery Made by Prof
Barnard With the Lick
Telescope.
"A Astronomical Achievement
Regarded a. the Best Of tho
Century.
r. . Field We'll Nigh Wsrn Out A. Add
ton to the Solar system 10
Found.


fifth satellite TO the -four satellites Of Ju-
pitsr discovered by Calico on January z,
(61O. II was discovered BY Barnard On
September 10. lts period i about twelve
nours and thirty-six minutes. Its distance
rom the planet center il about ll2,AoO
miles. II was observed by him at east
~piongation September 10. twenty hours and
hfty-three minutes and tweaty-one seconds
Greenwich mean tine. Its magnitude II
he thirteenth. The discovery Of this sat
lllits 10 looked upon a. tbs greatest sstro-
nomical a~chisvsnent Of the seatury. II
means the addition OF another bsdy to the
golar system, which il in these daya . most
stupsndSus discovery. II Is far g~rsater
thai the finding Of The satellites Of Mars,
TOR these two bodies were more
Or less easy of observation. Bar
nard's work makes an addition
70 the solar family in . field that was we'll
nigh worn out. and which was thought to
have bssn 20 thoroughly siftsd that "stroA-
omers gave NJ the task Of looking for frssh
facts. Then. too. Jupiter has ''een the most
observed OF all tho planets, for the reason
that it 10 30 ve,y large and such . grand
body withal that itinvitss inspection. This
10 the hrst good work OF any nonsnt that
has been done with TIA Lick telescope. and
If such observation az this 10 continued ths
big glass will serve to bring on new lights
in the universe and turn up startling dis
coveriss at the most unexpected places.
During the present opposition OF Mars
the moons have besn repeatedly observed.
not only at Washington, but through tho
r {nIy kalnn~0AA ir fVnIIfnppiA y hR
stupendous instruments, with ito thirty six
inch object glass. in the observations OF
Mars not only justified all the expectations
which had been formed Of ii by showing
the strange lights and the markings on the
polar cap. but it has now happily crowned
its achievements of the year by adding an
other body to the planetary system ~ de-
tined in the text books of astronomy. The
satellites Of Jupiter have already played a
most important part in the advances which
have been made in ~astronoMy and they
have indirectly been tho means of throwing
much light upon Obscure problems In the
collateral sciences. Thus 1t was through
the moons OF Jupiter that the rate at which
light travels was FIRST discovered. The
moons had been first discovered BY Calico.
With the advances in astronomy, how
ever, and especially 10 Misunderstanding
beehms more and moro perfect and object
lenses got larger and larger. it was found
that something queer was going on In re-
gard to ths moons of Jupiter. The motions
OF that immense planet had been calculated
to a niosty. a. we'll as the motions Of it's
moons. md astronomers knew to \ fraction
Of q second when one and all should be at
q given place in the heavens. At this time
the NEST difficult problem before astron
omers was to find Bome means OF exactly
determining the longitude at sea, the alb
senos of which rendered all navigation dan
gerOus and uncertain. 1t then came to be
believed that this could alone be determined
bv observing tho oclipses and oocultations
of Jupiter ana its moons. Tho more the
latter were obse we'd. however, the more
I'M ,eliable they seemed to become. They
moved about the planet in \ way that
wholly upset tho theories of the MS
tronomers. Not only did the moons OF
Jupiter appear and disa in q way that
was very bewildsrinp. but they actually diff
at the same time. The hope Of by their
means determining longitude At sea had
therefore to be finally abandoned. as to be
of any value for such a purpose their mo
tions would have to be exactly known. At
the same time the causes Of their eccentric.
tiles were a mystery. One of the fou;
moons for a tims would seem to follow its
orbit with regularity, but No sooner would
its motions be determined than it would
begin to va y, apd then one or more OF the
others perhaps would seem to fall into the
line of regularity, only. to ~disappoins the
astronomers at tho last moment and 2psst
all their oalculatioue.
The means by which the movements OF
such heavenly bodies are determined are
their appearance and disAppsarsnce during
periods Of eclipse. The exact moment OF
contact can thus be determined when tvs
bodies approach each oth0r and one
passes in behind the other. and If the cal
- Ill L.. l----,~ l3
nitely not only the Instant when tbs disc
will begin to reappear OH this other side
but the number of seconds which viii
elnpse before Its last segment comes into
view. In spite of the work of centuries
however, it WAS impossible to tell where III,
moons of Jupiter would be found II va,
known where they ought to be, but very
oftsn they were not there at all. Their
was apparently no key to this mystery nnti
Roemer, the great asst onomer, stepped for
ward with m OK planatlon of tho phencm
ena. His explanation was 30 extraordinary
that tho first astronomers of the time 70
ceivsd it with ridicule and i%ncrsdulity
He said that when the moons wer'
seen at certain times they were no
there at all, aud that at other times, whel
all four moons could be plainly seen, il wa
only their light which the We
looking at, and that they thsmselves wer,
elsewhere. or arouad on the othsr side 0
the planet. This theory. in short, WAS tina
the moons Of Jupiter eould not be seen .
all, but that only ghost moon had boel
observed during all these years. The dis
tanes. said RoeDsr, was 10 grest-over 400.
OOO, 900 miles from the sarth-that the ligh
of the moons took a long time to trsvo
across the space, and that when u man wa
looking through 4 telescope At one OF them
which he ooald plainly SEQ ON . clear night
there was no moon thers at all. only sMpt,
air filed with light, while the moon WAS II
another place. but invisible because IL
light bad not yet reached this earth.
It will rendily be seen that il tins theor,