The weekly Iberian. (New Iberia, La.) 1894-1946, 1910-04-02
CONDENSED FACTS
ABOUT HAL
LEY'S COMET.
BY n. w. GRIGGS.

A few facts presented in a condens-
ed form may possibly interest the
readers of the Scientific American
who wish to follow the course of Hal
ley's comet in the heavens during its
present appearance.
The last perihelion passage occurred
on November 18th, 1888. The present
perihelion passage VIII occur on April
10Th. 1910. The periheliOn distance
will be 0.5S7, and the aphelion dis
tance will be 800. The eccentricity
is 0.967, the longitude of ascending
node is 81 deg. l6 min, the node and
apsis angle IS ! IL deg. A m1n., the in
cinaton Of the orbit is (162 deg. y
min. plus II deg 4S min. =, the long
itude Of perhelion is 303 deg. plus and
the motion is retrograde, in other
words opposite that of the planet
The diameter of the nucleus cannot of
accuracy at the present time, but 1t IS
not likely to exceed 10000 miles.
At the end Of February Prof. Barn
ard Of Nerkes Observatory estimated
the tail to be 4,O00.0 600 miles long.
Just before and after perihelion pass
age the tail will be at least that long,
and probably longer. The comet is
fast approaching its perihelion point,
or point nearest the sun, where, as we
have said, it is due to arrive on April
Goth. During the months Of February
and March. the earth and the comet
are racing on practically parallel Or
bits, 10 600, 600 miles apart on OppOs
itc sides of the sun.
The comet first crossed the earth's
orbit about March 10th at point
where the earth will arrive at the mid
die of next October, but far above
where the earth will be. SO to speak,
for it will be some l0,OOO,0OO miles
above the plane of the ecliptic. In
April the comet will emerge from be-
hind the sun, and will become visible
to the naked eye in the eastern sky be-
fore sunrise.
On April Goth, when the comet will
swing around the sun, it will be ST.
600 900 miles away from the sun. Its
velocity will be 26 miles second. The
earth travels at about 10 miles sec
ond. On May md the comet will ira
verse the orbit Of Venus, some 6,OOO.-
600 miles above the planet. In other
words, an astronomer on Venus would
find the comet a far more impressive
spectacle than a terrestrial astrOnO-
mer. AS it rushes on. Halley's comet
will pass between the earth and sun
close to its ascending node. On May
18th the earth will be about $1,000, 900
miles away from the nucleus or head,
as against 100000 miles in 1885.
Moreover, on May 18th the earth will
be enveloped in the comets tail for
few hours. A few days later the COM
ct will be visible in the western sky
after sunset with 15 deg. or 20 deg.
splendor. After that 1t will speed
away from the solar system. The last
glimpse of 1t with the naked eye will
be obtained probably at the end of
June. 1t will not reappear for seven
ty-tive years.
Halley's comet is noteworthy be-
cause it was the first comet for which
an orbit was plotted and time table
1t has a history more or
less identified with the history Of hu
man thought and civilization. The
dread with which it was
regarded in medieval and ancient
times swayed many a monarch. 1t
was instrumental in forming the poll
cies OF Louis lie Debonnaire in 837. It
blazed in the sky when the Turks
to overrun Europe in 1855,
and when the Reformation was at its
height in 1881. It struck terror to the |
Saxons under Harold in 1866. when |
they were conquered by William of
This fear of the middle |
ages was dispelled only when HALEY |
made his great prediction in 1852 that
AZ ss>
diction which was verified after the
great astronomer was in his grave.
A comet which has reappeared regu-
larly for over two thousand years
must be composed of fairly enduring
stuff. just what its composition may
be, the present temperance will for
the first time enable us to tell. for in
1885 the spectroscope was not invented,
nor astronomical photography per-
fected. Scientific American.