Mars
Neptune
Diameterkm
6,779
49,528
Mass (Earth = 1)x
0.11
17.15
Surface Gravitym/s²
3.72
11.15
Mean Temperature°C
-65
-214
Distance from SunAU
1.52
30.07
Orbital Perioddays
687
59,800
Day Lengthhours
24.66
16.11
Known Moons
2
16
Axial Tilt°
25.19
28.32
Orbital Velocitykm/s
24.07
5.43
Quick Facts
Mars
- -Olympus Mons on Mars is about 21.9 km tall -- nearly three times the height of Mount Everest.
- -A Martian day (sol) is 24 hours and 37 minutes, remarkably similar to an Earth day.
- -Mars has seasons like Earth because its axial tilt (25.19°) is very similar to Earth's (23.44°).
- -Dust storms on Mars can grow large enough to engulf the entire planet and last for months.
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.