Editing Planets beyond Neptune (section)

=== Planet X disproved ===
Harrington died in January 1993, without having found Planet X.<ref name="croswell66">Croswell (1997), p. 66.</ref> Six months before, [[E. Myles Standish]] had used data from ''Voyager 2'''s 1989 flyby of Neptune, which had revised the planet's total mass downward by 0.5%—an amount comparable to the mass of Mars<ref name="croswell66" />—to recalculate its gravitational effect on Uranus.<ref>{{Cite journal |last=Standish |first=E. M. |date=May 1993 |title=Planet X - No dynamical evidence in the optical observations |journal=The Astronomical Journal |volume=105 |issue=5 |pages=2000 |bibcode=1993AJ....105.2000S |doi=10.1086/116575}}</ref> When Neptune's newly determined mass was used in the [[Jet Propulsion Laboratory Developmental Ephemeris]] (JPL DE), the supposed discrepancies in the Uranian orbit, and with them the need for a Planet&nbsp;X, vanished.<ref name="standage" /> There are no discrepancies in the trajectories of any space probes such as ''[[Pioneer 10]]'', ''[[Pioneer 11]]'', ''[[Voyager 1]]'', and ''[[Voyager 2]]'' that can be attributed to the gravitational pull of a large undiscovered object in the outer Solar System.<ref>Littman (1990), p. 204.</ref> Today, most astronomers agree that Planet&nbsp;X, as Lowell defined it, does not exist.<ref>{{Cite book |last=Standage |first=Tom |url=https://archive.org/details/neptunefilestory00stan/ |title=The Neptune file: a story of astronomical rivalry and the pioneers of planet hunting |date=2000 |publisher=Walker |isbn=978-0-8027-1363-6 |location=New York |page=[https://archive.org/details/neptunefilestory00stan/page/168 168] |url-access=registration}}</ref>