Astronomy 101: From the Sun and Moon to Wormholes and Warp Drive, Key Theories, Discoveries, and Facts about the Universe (Adams 101 Series)

by Carolyn Collins Petersen

letters were also a salute to Percival Lowell, who had died some years earlier. Later, it turned out that the extra perturbations in Uranus’s and Neptune’s orbits were the result of a mathematical error, and not due to Pluto’s influence.