(1846) THE DISCOVERY OF NEPTUNE, Sir Oliver Lodge


Among modern astronomical discoveries none has been regarded as more
important than that of Neptune, the outermost known planet of the solar
system. It was a rich reward to the watchers of the sky when this new
planet swam into their ken. This discovery was hailed by astronomers as
"the most conspicuous triumph of the theory of gravitation." Long after
Copernicus even, the genius of philosophers was slow to grasp the full
conception of a spherical earth and its relations with the heavenly
bodies as presented by him. So it was also with the final acceptance of
Newton's demonstration of the universal law of gravitation (1685),
whereby he showed that "the motions of the solar system were due to the
action of a central force directed to the body at the centre of the
system, and varying inversely with the square of the distance from it."
After making this discovery, Newton himself, with the aid of others,
especially of the French mathematician Picard, labored for years to
verify it, and still further verification was necessary before it could
be fully comprehended and accepted by the scientific world. The
discovery of the asteroids or small planets revolving in orbits between
those of Mars and Jupiter, aided in confirming the Newtonian theory,
which the discovery of Uranus, by Sir William Herschel (1781), had done
much to establish.

From the time of Sir William Herschel the science of stellar astronomy,
revealing the enormous distances of the stars--none of them really
fixed, but all having real or apparent motions--was rapidly developed.
The discovery of stellar planets, at almost incalculable distances,