The morning news. [volume] (Savannah, Ga.) 1887-1900, 1889-03-07
CELESTIAL VISITORS.
Where Comets Come From and How
They are Found.
From the Washington Star.

They are Found.
From the Washington Star.
reporter asked George A. Hill, who i;
now engaged at the naval observatory
searching for comets, to explain how these
strange celestial visitors are found.
II imagine" replied Mr. Hill, that read
ers would be very anxious to learn all about
this subject should bright comet, with q
tail 30 or 40 degrees long, suddenly appear
In the heavens, but as that phenomenon is
quite rare, the three comets now vi ible by
AID Of the telescope would not excite mucn
interest on the part Of the casual observer
Comets, whether faint or bright, are,
however, interesting objects for study, and
we will continue to observe these until they
pass out of sight. To my mind comet is
the most wonderful Of al celestial b5dies
Not in the sense Of its size or Importance in
our solar system. but because Of the mys-
terry that surrounds it, Did you ever stop
to consider that ~ per cent. Of the comets
observed each year have never before been
seen by mortal eyesl Where do they come
froms do not know.
TRAVELLING THROUGH SPACE.
The moon, planets and stars shine to-
night with the same splendor, and look
down upon US Just as they did when the
builders of the pyramids were carving out
the stone that was used in building that
monument, 5000 years ago. But I VEN
ture TO say, that the two little comets now
sweeping through our skies, we're at that
time passing through a portion of stellar
space of which we have not the slightest
conception. They have been all these
years gradually drawing nearer to
the sun, and in the year 1889 we are per-
mtted to observe them for a time and
they are gone forever. In its journey
through space a comet moves ia one
of three curves, an ellipse, e parabola or a
hyperbola. If the comet mo eS in an clip
teal orbit il will return again to the sun.
Ii in an orbit of a parabolic nature the
comet rushe5 10 ward and around the sun,
and then passes off into space never again
TO be observed by us. Two of the comets
now in view are moving in a parabol C
orbit, and they will soon be lost to our
sight. The third, Faye's, named after its
discoverer, is moving In an ellipJical orbit,
which it takes about seven and a half years
to complete. This comet has just approached
the sun for the fifth time since it was dis
covered.
SEARCHING FOR COMETS.
"In searching for these cratic objects, "
said Mr. Hill, 81 use telescope Of peculiar
construction, and one that was made especi-
ally for the purpose. As a rule bright
comets are found near the sun. As soon as
darkness comes on sufficient to permit faint
stars TO be seen | commence to sweep along
the southwestern, western and northwestern
horizon, starting as low down as possible
AMI sweeping in horizontal zones upward
toward the zenith In the morning
sky l sweep in the eastern portion of
the heavens, and from the zenith toward
the horizon. The eye-piece of my telesco pe
is so constructed that / am able to observe
at one time about degree and a half of
the sky, or, in other words, if the moon
was about three times as large as at present
it would Just fill the field of view as seen in
the eye-piece. BY having so large field I
am able to sweep rapidly AID at the same
time observe all objects that appear in the
telescope.
HOW THEY APPEAR.
Comet as a rule first pre- cent themselves
to our view III e. form OF a watery-look-
log nebulouS mass of matter, with a slight
central combination. They commence to
grow brighter, and shortly bright point
or nucleus Is seen. II the comet is large
and approache5 relatively near the earth a
tail is observed to follow it. Tne comet
may continue TO grow brighter until it
bursts korta before our eyes in all the
splendor of such objects as the great
comets of 1913, 1853, 1881, 1874 aud
1882. The average of those that rush
into our system are small or to- far
away from the earth to make much of a
show and their presence is known only to
observers VINO are interested in that par
ticular branch of astronomical science.
The great obstacle observers searching for
comets have to contend with is the nebuiR
that are scattered all over the heavens. A
faint comet and faint nebGi8 are striIingl7
similar in appearance, and comet seek err
must he thoroughly conversans with all
nebulR thai can be seen in MS telescope to
be aol9 TO detect the former from the latter.
The true character of a cometary looking
object is soon decided after it has been ex-
amined. NebulR do not move, but retain
their relative pOSltiO IS with respect to the
stars situated near them. A comet, on the
contrary, is continually in motion, and an
hours time after its discovery is generally
sufficient to observe it approach and pass a
star situated near it.
'Iu the United States there are two OBJ
servers besides myself who are constantly
engaged in this branch of asst onomical re-
searcl-namely, Prof. Brooks OF Geneva,
n. Y, and Prof. Barnard Of the Lick OBJ
servatory on Mount Hamilton.
THE TOTAL NUMBER OF COMETS
that have been discovered, aud of which
we nave accurate observations is something
less than 800. For the past fifteen or eiga-
teen years the average has been three or
four year. Some time during the period
from 1909 to 1912 one Of the most maguif-
cent comets of all ages will return to our
view This is the great comet known as
Haley's comet, whose period Is about
seveuty-fiye years. This object has now
passed Is most distant point from the sun,
and is returning to lis. Those OF US who
live until 1919 will have the pleasure of
seeing this beautiful object, which has been
out in space on three-quarters Of century
journe;, far b yond the orbit If Neptuae,
come back again to our sun and fulfill that
great law that controls all heavenly bodies,
tue law of gravitatiOn,n