ALREADY DISCOVERED (1879), 192. DISTANCES FROM THE SUN, FROM 200,000,000
TO 315,000,000 MILES. DIAMETERS, FROM 20 TO 400 MILES. MASS OF ALL,
LESS THAN ONE-QUARTER OF THE EARTH.
The sense of infinite variety among the countless number of celestial
orbs has been growing rapidly upon us for half a century, and doubtless
will grow much more in half a century to come. Just as we paused
in the consideration of planets to consider meteors and comets,
at first thought so different, so must we now pause to consider a
ring of bodies, some of which are as small in comparison to Jupiter,
the next planet, as aerolites are compared to the earth.
In 1800 an association of astronomers, suspecting that a planet
might be found in the great distance between Mars and Jupiter,
divided the zodiac into twenty-four parts, and assigned one part to
each astronomer for a thorough search; but, before their organization
could commence work, Piazzi, an Italian astronomer of Palermo, [Page
163] found in Taurus a star behaving like a planet. In six weeks it
was lost in the rays of the sun. It was rediscovered on its
emergence, and named Ceres. In March, 1802, a second planet was
discovered by Olbers in the same gap between Mars and Jupiter, and
named Pallas. Here was an embarrassment of richness. Olbers
suggested that an original planet had exploded, and that more pieces
could be found. More were found, but the theory is exploded into
more pieces than a planet could possibly be. Up to 1879 one hundred
and ninety-two have been discovered, with a prospect of more.
Between 1871-75 forty-five were discovered, showing that they are
sought for with great skill. In the discovery of these bodies, our
American astronomers, Professors Watson and Peters, are without
peers.
Between Mars and Jupiter is a distance of some 339,000,000 miles.
Subtract 35,000,000 miles next to Mars and 50,000,000 miles next
to Jupiter, and there is left a zone 254,000,000 miles wide outside
of which the asteroids never wander. If any ever did, the attraction
of Mars or Jupiter may have prevented their return.
Since the orbits of Mars and Jupiter show no sign of being affected
by these bodies for a century past, it is probable that their number
is limited, or at least that their combined mass does not approximate
the size of a planet. Professor Newcomb estimates that if all that
are now discovered were put into one planet, it would not be over
four hundred miles in diameter; and if a thousand more should exist,
of the average size of those discovered since 1850, their addition
would not increase the diameter to more than five hundred miles.
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That all these bodies, which differ from each other in no respect
except in brilliancy, can be noted and fixed so as not to be mistaken
one for another, and instantly recognized though not seen for a
dozen years, is one of the highest exemplifications of the accuracy
of astronomical observation.