Uranus
Mercury
Diameterkm
50,724
4,879
Mass (Earth = 1)x
14.54
0.06
Surface Gravitym/s²
8.87
3.70
Mean Temperature°C
-220
+167
Distance from SunAU
19.19
0.39
Orbital Perioddays
30,589
87.97
Day Lengthhours
17.24
4222.60
Known Moons
28
0
Axial Tilt°
97.77
0.03
Orbital Velocitykm/s
6.80
47.36
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.
Mercury
- -Mercury's day-night cycle lasts 176 Earth days -- longer than its year of 88 Earth days.
- -A person weighing 68 kg on Earth would weigh only 25.7 kg on Mercury.
- -Mercury has ice in permanently shadowed craters near its poles despite surface temperatures reaching 430°C.
- -Mercury is shrinking -- its circumference has decreased by about 14 km as its core slowly cools and contracts.