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Curiosities of the Sky by Garrett P. (Garrett Putman) Serviss
page 115 of 165 (69%)
But the adventures of comets are not confined to possible encounters
with unknown obstacles. We have referred to the fact that the great
planets, and especially Jupiter, frequently interfere with the motions
of comets. This interference is not limited to the original alteration
of their orbits from possible parabolas to ellipses, but is sometimes
exercised again and again, turning the bewildered comets into
elliptical paths of all degrees of eccentricity. A famous example of
this kind of planetary horse-play is furnished by the story of
Lexell's missing comet. This comet was first seen in 1770.
Investigation showed that it was moving in an orbit which should bring
it back to perihelion every five and a half years; yet it had never
been seen before and, although often searched for, has never been seen
since. Laplace and Leverrier proved mathematically that in 1767 it had
approached so close to Jupiter as to be involved among the orbits of
his satellites. What its track had been before is not known, but on
that occasion the giant planet seized the interloper, threw it into a
short elliptic orbit and sent it, like an arrested vagrant, to receive
sentence at the bar of the sun. On this journey it passed within less
than 1,500,000 miles of the earth. The form of orbit which Jupiter had
impressed required, as we have said, its return in about five and a
half years; but soon after 1770 it had the misfortune a second time to
encounter Jupiter at close range, and he, as if dissatisfied with the
leniency of the sun, or indignant at the stranger's familiarity,
seized the comet and hurled it out of the system, or at any rate so
far away that it has never since been able to rejoin the family circle
that basks in the immediate rays of the solar hearth. Nor is this the
only instance in which Jupiter has dealt summarily with small comets
that have approached him with too little deference.

The function which Jupiter so conspicuously fulfills as master of the
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