Page 52 - Ultimate Visual Dictionary (DK)

THE UNIVERSE

Neptune and Pluto TILT AND ROTATION OF NEPTUNE
Axial tilt
of 28.8° Perpendicular to
orbital plane
Axis of
NEPTUNE IS the farthest planet from the Sun, rotation
at an average distance of about 2.8 billion miles
North
(4.5 billion km). Neptune is the smallest of the
Pole
giant planets and is thought to consist of a small
rocky core surrounded by a mixture of liquids and
gases. Several transient cloud features have been
observed in its atmosphere. The largest of these
FALSE-COLOR Orbital
IMAGE OF NEPTUNE were the Great Dark Spot, which was as wide as plane
the Earth, the Small Dark Spot, and the Scooter.
The Great and Small Dark Spots were huge storms that were swept South Pole
around the planet by winds of about 1,200 miles (2,000 km) per hour. One rotation
The Scooter was a large area of cirrus cloud. Neptune has six tenuous takes 16 hours
and 7 minutes
rings and 13 known moons. Triton is the largest Neptunian moon and
the coldest object in the solar system, with a temperature of -390°F CLOUD FEATURES OF NEPTUNE
(-240°C). Unlike most moons in the solar system, Triton orbits its Great Dark Spot
mother planet in the opposite direction of the planet’s rotation. (anticyclonic
wind storm)
The region extending out from Neptune’s orbit is populated by
Kuiper Belt objects and dwarf planets. They make a doughnut-
shaped belt called the Kuiper Belt. The Kuiper Belt objects are a
mix of rock and ice, irregular in shape, and less than 600 miles Scooter (cirrus
(1,000 km) across. The larger dwarf planets, which include Pluto, cloud)
are almost round bodies. Pluto was the first object discovered
beyond Neptune and was considered a planet until the dwarf
planet category was introduced in 2006. It is made of rock and ice
Small Dark Spot
and is 1,365 miles (2,274 km) across. It has three known moons.
(cyclonic wind
The largest, Charon, is about half Pluto’s size and the two storm)
probably had a common origin.
HIGH-ALTITUDE CLOUDS
RINGS OF NEPTUNE Methane cirrus clouds
Adams ring and unnamed 25 miles (40 km) above
ring on its inner edge main cloud deck
Cloud shadow
Arago ring
Lassell ring Main cloud deck
blown by winds at speeds
of about 12,000 miles
Le Verrier ring (2,000 km/h)
MOONS OF NEPTUNE
Galle ring

TRITON PROTEUS
Diameter: 1,681 miles Diameter: 259 miles
Average distance from Average distance from
planet: 220,500 miles planet: 73,100 miles