Evening star., 1901-12-20
HUNT FOR ANOTHER PLANET
AN UNSEEN WORLD OUTSIDE NEP.
TUNES ORBIT.
Prof. Forbes Theory Regarding the
BOdy-stellar Photography.
From the London News.

From the London News
| The name of the first discoverer of a
planet Is as completely lost in the dark
backward and abysm of time that of
| the man who first ate an oyster or sailed
a boat. 1t is even more obscure, in fact,
for Mr.. Watts has given us picture of the
anticipator OF Dando. and the rationalizecs
of Greek mythology attribute the inven-
tion Of the sail to Daedalus. But 1t is
hopeless to look for any reference to the
first shepherd watching his fiocks by night
who satisfied himself that five of the stars
did not preserve the same relative position.
as all the consultations seemed to do.
These five stars were called the wander
ers," or planets, in opposition to the fixed
| stars, and the sun and moon were classed
with them. When astronomy emerged from
the mists Of antiquity it already possessed
this amount Of information, which was un-
changed for some thousand years. Gallileo
| was the first to whom we can assign the
| discovery Of new member Of the solar
system-not a planet In this case, but the
four satellites of the planet Jupiter. 1t is
amusing to recall the objections that were
/ leveled against this first revelation Of his
wonderful telescope.
A Typical Objection.
| typical one is quoted by Principal
Lodge from the work of a Florentine
| astronomer, who thus argued against any
attempt to increase the number of the
p,anets-in which the sun and moon were
then. included-"There are seven windows
| in the head, two nostrils, two eyes, two
| ears and a mouth; so in the heavens
there are two favorable stars. two un-
propitious, two luminaries and Mercury
| alone undecided and Indifferent From
| which and many other similar phenomena
| OF nature, such as the seven metals, SC,
| which it were tedious to enumerate, we
gather that the number Of planets is neces-
sarily seven. Besides. the Jews and
| other ancient nations, as well modern
Europeans, have adopted the division Of
I the week into seven days, and have named
them them from the seven planets. Now If we
| whole system falls to the ground" 1t was
an argument worthy Of an age when medi-
| cal science accepted the doctrine of sigma
| lures. and so held, for instance, that the
| eyebright-Milton's euphrasie-was good
| for sore eyes, because Of the black pupil
like spot In it's corola. But It did not long
hold out against the testimony of the tele-
| scope, and no argument of the nature
| Is likely to be used against Prof
| George Forbes hypothesis of the existence
of an unseen planet beyond the orbit of
| Neptune. and separated from the sun by
| more than three times the distance of that
| planet at present believed to be the out
| post of the solar system. Prof. Forbes,
| who has maintained the proba bility of such
a planet for at least twenty years, has
| lately brought forward some new and
stronger arguments in favor Of its exist
| Society Of Edinburgh went so far as to
point out its probable situation. We hope
| that some search will be duly made for it.
| and that the singular apathy with which
| Adams famous discovery of Neptune was
! received by the heads of English obser-
vatories will not be repeated.
Attraction Of the Sphere.
| 1t is truly amazing thing that astrono-
| mers should now possess a method of in
vestigation which enables them to detect
| planet, by far-reaching mathematical an
| alysis long before the most powerful tele-
| scope has distinguished 1t from a fixed
| star Prof. Forbes planet may or may not
| exist in reality, but the possibility of it's
| discovery being made by such method as
| he has used was definitely established by
| the discovery Of Neptune. Up to the mid
| die of the last century such additions as
had been made to the Copernican solar sys-
| tenn had been solely due to the increased
| power of telescopes and the diligence of
| their users First the satellites of already
known planets We're discovered. Then
came, in 1881, the discovery of new plan
| ct, Uranus, the first that had been. added
to the number of actual planets since the
history of astronomy began. 1t was due to
HerschepS sheer perserverance-amount
almost to genius-in watching the sky. On
the first day of the nineteenth century
Piazzi, by similar perseverance and good
fortune. discovered the first of the small
planets" or asteroids, of which We now
know that at least 500 girde the sun be-
tween the orbits of Mars and Jupiter, and
probably extend even beyond these limits
as Shelley foresaw with the poets inspira-
ton when he spoke of
Those mysterious stars
which b1de themselves between the earth and
Mars.
Discovery of Neptune.
But the discovery of Neptune In 1S46
marked a new epoch. Adams Of Cambridge
and Leverrier of Paris independently
worked out a problem so difficult that no
one had previously ventured to tackle it,
Newton's great law of universal gravita-
outermOst of the planets then known had
been going wrong for years. His place
as shown by the telescope was slightly diff
ferent from that which calculation pre-
dicted that he would occupy, and the dis
crepancy was increasing. 1t was q very
tiny difference far too small for the naked
eye to detect, even If there had been a Sec
ond Uraus holding the calculated position,
but 1t very important. Every disturb
for, Of course the planets attract one an
other, just as the sun attracts them, and so
they are always more or less "perturbed"
from the orbits which they would describe
if only the sun had to be considered Ad-
ans and Leverrier in entire ignorance of
one another's work, simultaneously set out
to discover whether the unexplained dis
crepancy between Uranus real place and
that predicted for him could be due to per-
further from the sun, and If so, whether
they could discover the true position of
this planet by calculation alone.