Uranus
Neptune
Diameterkm
50,724
49,528
Mass (Earth = 1)x
14.54
17.15
Surface Gravitym/s²
8.87
11.15
Mean Temperature°C
-220
-214
Distance from SunAU
19.19
30.07
Orbital Perioddays
30,589
59,800
Day Lengthhours
17.24
16.11
Known Moons
28
16
Axial Tilt°
97.77
28.32
Orbital Velocitykm/s
6.80
5.43
Quick Facts
Uranus
- -Uranus rotates on its side with an axial tilt of 97.77°, likely caused by a massive ancient collision.
- -Uranus was the first planet discovered with a telescope, found by William Herschel in 1781.
- -All 28 of Uranus's moons are named after characters from Shakespeare and Alexander Pope.
- -Uranus's blue-green color comes from methane in its atmosphere absorbing red light.
Neptune
- -Neptune has the strongest winds in the solar system, reaching speeds of up to 2,100 km/h.
- -Neptune was the first planet discovered through mathematical prediction rather than observation.
- -One year on Neptune lasts about 165 Earth years -- it has completed just one orbit since its discovery in 1846.
- -Neptune's moon Triton orbits backward (retrograde), suggesting it was captured from the Kuiper Belt.