The sun., 1910-02-06
WE'LL BUDGE HALLEY'S COMET
THOUGH IT'S A MILLION TIMES
BIGGER TEAM THE EARTH.

For II IL Gaseous. while the Earth ID Solid
Nearest on May l0-Observers OF
10 Hawaii 10 Oct . Good LeoaS
Some TIpS Frem Prof. Frost,
CHICAGO. Feb. 5.--Prof. Edwin b. Frost.
director OF the Yerkes observatory at
williams Bay. Wis. said to-day: -Halley's
comet, on which all eyes in the astro-
nomical world are now centred. IL about
1000. 900 times as big as the earth. Yet
although the earth's gravity may change
the orbit OF the comet the earths path
through the sky will be unaffected by the
approaching proximity Of the two bodies"
This supplements Information con-
tanned in circular respecting observa-
ton OF Halley's comet. 1870" which has
just been issued by the Astronomical
and AstrophysicaI Society OF America
The circular says. that an expedition to
observe and photograph Halley's comet
Tron, the Hawaiian Islands is to be sent
out by the society. and sets forth that:
In view OF possible large perturba-
lions arising from the close approach
OF the comet to Venus on May and TO the
earth on May Ic meridian observations
are especially desired during the period
in which the comet is sufficiently bright
for that purpose
What are these possible large per-
rurbations'Y" Prof. Frost was asked.
That merely means was the reply.
that on those dates the comet will be near
enough to the planets mentioned to he
affected by their attraction"
will that Affect their orbitsl"
lit won't Affect the orbit OF Venus or OF
tho earth. but it is likely to affect the COM
cts orbit. That is one reason why We
want 10 get meridian observations, which
will show almost exactly these OrbitL
changes.
There will be an interesting spectacle.
by the way, on May /, when the comet
IA near TO Venus The planet and the
comet will be practically the same distance
from the earth and every one will he
able TO see their relative size.
The comets bulk exceeds that OF
Venus about 1000. 600 times. It 10 not
solid matter, however. II ls gaseous
and IT'S mass is comparatively slight.
Therefore its attraction will not Affect
the planets. while the solid heavy planets
are likely TO affect IL a good deal. The
earth and Venus are about the same size.
so that the earth too is about one-mil-
lionth OF the size OF the comet
Frederick Ellerman Of the Solar Observ-
atory at Pasadena. Cal. win head the
Hawaiian expedition
The circular on Hallsys comet was
issued by the committee on comets Of
the socisty. On this committee are Profs.
Ge0rge O.. Comstock Of Madisou. Wis:
Edward z. Barnard and Edwin B. Frost
OF ths Yerkes observatory. Charles d.
Perriue and Edward G. Pickering Qf
Harvard University. Says the circular:
The close approach OF the comet Co
the earth promises unusual opportunity
for a study OF the physical conditions
that obtain in such a body, and as an
indispensable basis for such study tho
committee recommends a Photographic
campaign a. long and az nearly contin-
uous as pcseibie. The comets close
proximity TO the suns direction at the
time Of maximum brilliance imposes
serious limitations upon this programme.
and widely extended cooperation will
be required throughout the whole cir
cult OF the earth IL this ideal OF q con-
tinuous Photographic record is to be
even remotely realised
"All meteors are bits Of solid matter
supposed to be debris of oomets-which
travel around in comets wakes con-
tinued Prof. Frost. They are not visible
unless they come within 100 miles Of
the earth-that is unless they come
within the earth's atmosphere.
The theory that n comets tail 10 longer
when it Is nearest the sun is somewhat
awry. Theoretically 1t would he so. be-
cause It is the reaction from the suns
light which causes the emanstion OF
streaming vapors that form the tail. BUT
actual observation shows that when a
comet s near the sun there are other
changes in its composition which offset
the greater force Of this reaction Of light.
A comets head. for. instance, shrinlos
when near the sun instead Of expanding
CARACAS. Feb. 5.-Halley's comet was
seen last night from the observatory here.