Mass of Uranus
| Value | 8.681e25 kg |
| Status | Measured: ± 1.90e+21 kg (0.000022 relative) |
| Source | NASA planetary fact sheet; GM from Voyager 2 tracking and satellite orbits, divided by CODATA 2022 G |
| Categories | Astronomicalsolar-systemplanets |
| microgram | 8.6810000e+34 μg |
| milligram | 8.6810000e+31 mg |
| gram | 8.6810000e+28 g |
| kilogram | 8.6810000e+25 kg |
| metric tonne | 8.6810000e+22 t |
| ounce | 3.0621326e+27 oz |
| pound | 1.9138329e+26 lb |
| stone | 1.3670235e+25 st |
| US short ton | 9.5691645e+22 ton |
| grain | 1.3396830e+30 gr |
| unified atomic mass unit (dalton) | 5.2278204e+52 u |
Learning zone
William Herschel found Uranus in 1781 with a homemade reflector, the first planet discovered rather than inherited from antiquity, and doubled the known size of the solar system at a stroke. Its mass was later pinned down from the motions of its moons, and Voyager 2's single 1986 flyby remains the only close visit.
The mass is best known for what it could not explain: the planet kept straying from its predicted path, and Le Verrier and Adams independently used the residuals to compute where an unseen perturber must be. Galle found Neptune within a degree of Le Verrier's position in 1846 — the most spectacular vindication celestial mechanics has ever produced, and the same technique astronomers now use to infer unseen planets around other stars.