Los Angeles herald., 1910-05-10
GET UP, SLEEPERS;
COMET IS BRIGHT.
Mt. Wilson Observatory Declares
Celestial Traveller Can Now
Be Seen at Best
RARE PHOTOGRAPHS TAKEN
Carnegie Scientists AnaIyze Light
of Aerial Nomad'S Appen-
dage-TheorieS Vary
RARE PHOTOGRAPHS TAKEN

PASADENA, May 10.-The following
report of the observations of Halley's
comet was furnished The Herald yes
terday by the staff of the Carnegie
solar observatory on Mount wilson;
observations of Halley's comet have
been carried on regularly during the
last three weeks with the slXty-lhcn
rejecting telescope on Mount wilson
These have been of two classes. tlrst'
direct photographs, to study the form
and details of the head of the comet
and the structure and extent of the tai:
second. photographs Of it's spectrum, to
determine the nature of the material
entering into its composition.
"At present the comet is in one OF
its most favorable positions for OBJ
serving 1t has Just passed the point
at which it rises longest before the
sun. and from this time until May Is
II will approach the sun and become
more and more difficult of observation
On May 18 it crosses the sun, and after
that date it will become an object IN
the western sky, rapidly increasing III
its distance from the sun and rising
higher each successive evening.
"If the brightness Of the comet does
not decrease too rapidly. it is probable
that the most important observations
will be made after its passage across
the sun. since it will be favored by
dark sky a much longer time than at
present. On May IS the earth VIII pass
through the tail Of the comet at dis
tance of some 100000 miles from the
head, and two days later the earth
and the comet will be closest together,
about 100000 miles apart. Since the
tail of the comet is conservatively estl-
mated at 20,000,000 miles In length, II
is clear that the earth will pass
0f
May Is.
INTERESTING PHOTOGRAPHS
"The photographs of the comet taken
on Mount Wilson by Mr.. Ritchey and
Mr.. Faith show the presence of most
interesting structure, both in the head
and in the tail The head Of the comet
consists of bright nucleus surrounded
bv several envelopes, which vary In
appearance from day to day. The tail
of the comet also is interesting because
of the striking character of the struc-
ture which it shows. 1t is made up of
a great number of very narrow, fine
streamers radiating from the head of
the cont like the spokes of a wheel
and differing greatly in appearance on
successive days.
"These streamers are without doubt
of great Importance in connection with
the explanation of the formation of
recent theory, the tails of comets,
which always point away from the sun,
are due to extremely minute particles
of solid matter and gas which are
driven away from the sun by the pres
sure exerted by the light which the
sun sends out.
1.-THE analysis of the light of Halley's
comet made by Mr.. Adams and Mr..
Babcock with the spectroscope at
tached to the sixty-inch reflector
shows that it is composed very largely
Of cyanogen gas and other gases which
are combinations of carbon with nitro
gen. hydrogen or oxygen.
There is, however, in the spectrum
evidence that considerable amount of
the light of the comet is due also to
sunlight reflected by fine solid particles
present in the comet. The combination
of these two sources of light results in
q most interesting spectrum, consisting
of both dark and bright lines.
SPECTRUM VERY STRONG
'"The spectrum is very strong in the
green and yellow regions, and in the
latter region two lines which are char
acteristic of sodium are intensely
bright, showing the presence of sodium
gas. probably in large quantities. The
intensity of these lines is so great as
to give a distinct yellow color to the
head of the comet. 1t is clear from the
observations that cyanogen gas is pres
ent in considerable quantities, especial
" near the head Of the comet.
"It probably forms a smaller proper
ton Of the material of the tail, but
the observations as yet are not suffi-
cient to show this with certainty.
1.-THE density of the gases compos-
ing the tails of comets is almost in
conceivably small, much less. in fact,
than that of any vacuum which it is
possible to produce In any way in
our laboratories. This is we'll shown
by the fact that in the past observa-
tions have frequently been made on the
light of stars through the tails of
some of the greater comets. Although
the light in such cases sometimes ira
verses %, 900 900 or 30000000 miles Of
the space filled with the material COM
posing the comets tail, not the slight
est diminution Of light from the stars
has ever been observed.
"Under these circumstances it is, of
course, impossible to conceive that the
gases forming the comets tail could
penetrate into the earth's atmosphere
even to the slightest extent"