Who was the American astronomer involved in the search for a planet thought to explain apparent discrepancies in the orbits of the giant planets?
Carl Otto Lampland Carl Otto Lampland (December 29, 1873 – December 14, 1951) was an American astronomer. He was involved with both of the Lowell Observatory solar system projects, observations of the planet Mars and the search for Planet X.
John Johnson (astronomer) John Asher Johnson is an American astrophysicist and professor of astronomy at Harvard. He was a formerly a professor at the California Institute of Technology and a researcher with NASA's Exoplanet Science Research Institute.