DK Space: Neptune
Neptune is 30 times farther from the Sun than Earth, and has the most powerful hurricanes of any planet in the Solar System. It is a gas giant with faint rings. TRITON is the largest of its 11 known moons.
Table 11. NEPTUNE DATA
| Diameter (width) at equator | 30,779 miles (49,532 km) |
| Average distance from Sun | 2.795 billion miles (4.498 billion km) |
| Time to orbit Sun | 164.8 years |
| Time to spin around own axis | 16.11 hours |
| Mass | 17.2 x Earth’s mass |
| Gravity | 1.13 x Earth’s gravity |
| Cloudtop temperature | –328°F (–200°C) |
| Number of moons | 11 |
Neptune’s atmosphere is made of hydrogen, helium, and methane, flecked with wisps of white clouds. The methane gas makes the planet appear deep blue. Underneath, there is a vast liquid mantle, and a small core of silicate rock at the center.
Bigger than the planet Pluto, Triton is Neptune’s largest moon. It has the coldest surface in the Solar System, –391°F (–235°C).
Triton’s beautiful frozen surface is covered with icy craters and pinkish snow. In some regions, jets of nitrogen gas erupt like geysers and carry fine dust in the wind. This dust then falls and settles on the ground in dark streaks.
