Evening star. [volume] (Washington, D.C.) 1854-1972, 1930-03-15
NAVAL OBSERVERS
TO CHECK PLANET
Official Confirmation of
Trans-Neptunian Body Is
Sought by Almanac Office.
BY THOMAS r. HENRY.


The discovery of another major planet
beyond Neptune, approximately 4,000,-
100000 miles from the earth, may be
of considerable importance in the work
of the Naval Almanac ONCE.
Equivalent to a star Of the seven
tenth magnitude the -Neptunian
planet probably will be just on the edge
of visibility with the Naval ObServa-
tory's 26-inch telescope, which means
that 1t can be seen, If at all, only on
very clear night with no moonlight.
Thus little direct study will be possible.
But it will be the job of the Almanac
once to determine its orbit around the
sun and the effect of its gravitational
pull on the rest Of the solar system.
At present, Prof. James Robertson, d.
rector of the Almanac once explained,
it Is only an almost invisible spot In
the. heavens. Practically nothing can
be known about it, he said, until three
observations have been taken, giving
three points in its path around the
sun. From these can be calculated
roughly its orbit, and this, since they
all are tied together, will give some
approximation of its mass, distance,
velocity, inclination Of its orbit to the
plane Of the elliptic and its eccentricity.
VIII Never BE Lost.
From this point on, Prof Robertson
said, finer and finer calculations can
be made as more observations are OBJ
tanned until 1t will be possible to de-
ternine, to fine degree pr accuracy,
Just where the new plaAet can be
found at any time. Once discovered, it
never again viii be lost sight Of,
For years, the director said, Neptune,
whose orbit presumably was the bound
airy of the solar system, has not acted
entirely as was expected, according to
the law of gravitation, with the pull
upon 1t of all known heavenly objects
near enough to exert q measurable
gravitational effect taken into consid-
Grafton. Minute differences have been
found between its actual and calculated
positions, which could be explained only
on the assumption Of an unknown at
tracing mass further out. But the dis
lance was so great and the size Of the
mass which would cause the perturba-
tons so comparatively small that there
was little hope Of ever finding 1t in the
great mass of heavenly bodies. The dif-
ferences appeared so constantly and in
the same degree, he said, that they
could not be considered as observattonal
errors.
SIOw-Moving Body.
Since the new planet probably is a
very slow-moving body, compared to
the planets nearer the sun, Prof. Rob-
ertson said, 1t probably will be some
time before the three observations
necessary to start mathematical cal
culation will be available. Then much
will depend on the extreme accuracy OF
the observers.
The phenomena Of bodies within the
solar system, the director said, all are
calculated upon the gravitauonal Tor
mula that every object attracts every
other object directly as their masses
and indirectly as the square OF their
distances apart. Thus the new planet.
If its existence Is proven, would be held
to its path around the sun by the pull
of the sun calculated with reference to
its mass and distance. But all other
objects In the system also would exert
influences on 1t, which must be taken
into consideration and which greatly
complicate the problem.
The practical Importance Of such a
problem, said Prof. Robertson, Is partly
due to the spur which 1t applies 70 the
ingenuity of astronomers to solve 1t.
"Astronony," he said, "is the funda-
mental science. Practically all Of our
hiaher mathematics has come originally
from the solution of just such problems
as this. The more difacult the prob
lens the greater the ingenuity required.
we can see the importance Of this
when we realize that mathematics is
the foundation of the other sciences,
which apply to practical problems the
tools which it gives them"
Confirmation Unofficial.
The planet, he said, will be recog-
nized in the naval ephemeris only
when there has been some determine
ton of its orbit, so that observers will
know where to look for 1t and there
no longer is any doubt that it really Is
a member of the suns system. Thus
far the Naval Observatory has received
only unofficial confirmation Of the dis
| covery.
For the other members Of the solar
| system, he said, there are hundreds Of
accurate observations upon which their
paths around the sun can be calculated
| from year to year. Thus the whole
system works with a clocklike &C
| curacy.
| BY describing the new planet as q
star of the seventeenth magnitude, it
was explained, is meant that it is II
times fainter than the faintest star to
be seen with the naked eye, all brighter
stars being of minus magnitudes.