On the night of Sept. 23-24,
1846, astronomers discovered Neptune, the eighth planet orbiting
around the Sun. The discovery was made based on mathematical calculations of
its predicted position due to observed perturbations in the orbit of the planet
Uranus. The discovery was made using a telescope since Neptune is too faint to
be visible to the naked eye, owing to its great distance from the Sun.
Astronomers soon discovered a moon orbiting Neptune, but it took more than a
century to discover a second one. Our knowledge of distant Neptune greatly
increased from the scientific observations made during Voyager 2’s flyby in
1989, including the discovery of five additional moons and confirmation of dark
rings orbiting the planet.
