Earth
Pluto
Diameterkm
12,742
2,377
Mass (Earth = 1)x
1.00
0.00
Surface Gravitym/s²
9.81
0.62
Mean Temperature°C
+15
-230
Distance from SunAU
1.00
39.48
Orbital Perioddays
365.25
90,560
Day Lengthhours
24.00
153.29
Known Moons
1
5
Axial Tilt°
23.44
122.53
Orbital Velocitykm/s
29.78
4.67
Quick Facts
Earth
- -Earth is the only planet not named after a Greek or Roman deity.
- -Earth's rotation is gradually slowing -- days are getting about 1.4 milliseconds longer per century.
- -About 71% of Earth's surface is covered by water, but 96.5% of that water is in the oceans.
- -Earth's magnetic field has flipped its polarity hundreds of times over millions of years.
Pluto
- -Pluto was reclassified from planet to dwarf planet in 2006 by the International Astronomical Union.
- -Pluto's largest moon Charon is so large (half Pluto's diameter) that they orbit a point between them, forming a binary system.
- -Pluto's famous heart-shaped feature, Sputnik Planitia, is a vast plain of nitrogen ice over 1,000 km across.
- -One year on Pluto takes 248 Earth years -- it hasn't completed a single orbit since its discovery in 1930.