THE SOLAR SYSTEM

THE OUTER PLANETS:

JUPITER, SATURN, URANUS, &

NEPTUNE

JUPITER FACTS

• Distance from the Sun (AU): 5.3

• Radius (km): 71 000

• Mass (Earth Mass): 320

• Average Surface Temperature (ºC): -150

JUPITER

• Jupiter is the fifth planet from the Sun and

by far the largest. Jupiter is more than

twice as massive as all the other planets

combined (320 times Earth).

• Jupiter is the fourth brightest object in the

sky

JUPITER

• The gas planets do not have solid surfaces, their

gaseous material simply gets denser with depth

• Jupiter is about 90% hydrogen and 10% helium

• Jupiter probably has a core of rocky material

amounting to something like 10 to 15 Earth-masses.

JUPITER • Unlike Saturn's, Jupiter's rings are dark. They're

probably composed of very small grains of rocky

material. Unlike Saturn's rings, they seem to

contain no ice.

• Jupiter is just about as large in diameter as a

gas planet can be.

• Jupiter has 61 known satellites (as of May

2003): the four large Galilean moons, 34 smaller

named ones, plus many more small ones

discovered recently but not yet named

SATURN FACTS

• Distance from the Sun (AU): 9.5

• Radius (km): 60 000

• Mass (Earth Mass): 95

• Average Surface Temperature (ºC): -170

SATURN

• Saturn is the sixth planet from the Sun and the second largest.

• Saturn is the least dense of the planets; its specific gravity (0.7) is less than that of water

SATURN

• Saturn's rings are extraordinarily thin:

though they're 250,000 km or more in

diameter they're less than one kilometer

thick

• The ring particles seem to be composed

primarily of water ice, but they may also

include rocky particles with icy coatings.

SATURN

• Saturn is about 75% hydrogen and 25% helium with traces of water, methane, ammonia and "rock“

• Saturn's interior is hot (12000 K at the core) and Saturn radiates more energy into space than it receives from the Sun.

• Saturn has 30 named satellites plus one discovered in 2003 and as yet unnamed

URANUS FACTS

• Distance from the Sun (AU): 19.0

• Radius (km): 26 000

• Mass (Earth Mass): 15

• Average Surface Temperature (ºC): -215

URANUS "YOOR a nus"

• Uranus is the seventh planet from the Sun

and the third largest (by diameter). Uranus

is larger in diameter but smaller in mass

than Neptune.

• Uranus is composed primarily of rock and

various ices, with only about 15%

hydrogen and a little helium

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URANUS

• Most of the planets spin on an axis nearly

perpendicular to the plane of the ecliptic

but Uranus' axis is almost parallel to the

ecliptic.

• Uranus' blue color is the result of

absorption of red light by methane in the

upper atmosphere.

NOT YOUR ANUS

• Like the other gas planets, Uranus has

rings

• Uranus is sometimes just barely visible

with the unaided eye on a very clear night

• Uranus has 21 named moons and six

unnamed ones

NEPTUNE FACTS

• Distance from the Sun (AU): 30.0

• Radius (km): 25 000

• Mass (Earth Mass): 17

• Average Surface Temperature (ºC): -215

NEPTUNE

• Neptune is the eighth planet from the Sun

and the fourth largest (by diameter).

Neptune is smaller in diameter but larger

in mass than Uranus.

• Like a typical gas planet, Neptune has

rapid winds confined to bands of latitude

and large storms or vortices. Neptune's

winds are the fastest in the solar system,

reaching 2000 km/hour.

NEPTUNE

• Neptune's composition is probably similar

to Uranus': various "ices" and rock with

about 15% hydrogen and a little helium.

• Like Uranus and Jupiter, Neptune's rings

are very dark but their composition is

unknown.

NEPTUNE

• Neptune can be seen with binoculars (if you know exactly where to look) but a large telescope is needed to see anything other than a tiny disk.

• Neptune has 13 known moons; 7 small named ones and Triton plus four discovered in 2002 and one discovered in 2003 which have yet to be named

PLUTO

• Pluto is now considered to be a minor

planet or dwarf planet along with about 25

others that have been identified

• There are some who think Pluto would be

better classified as a large asteroid or

comet rather than as a planet

PLUTO • Pluto has not been visited by a spacecraft. Even

the Hubble Space Telescope can resolve only the largest features on its surface

• Pluto's orbit is highly eccentric. At times it is closer to the Sun than Neptune (as it was from January 1979 thru February 11 1999). Pluto rotates in the opposite direction from most of the other planets.

• Pluto is the farthest from the Sun (usually) and by far the smallest. Pluto is smaller than seven of the solar system's satellites including the Moon

PLUTO AND ITS PARTNER

• Charon is unusual in that it is the largest

moon with respect to its primary planet in

the Solar System. Some prefer to think of

Pluto/Charon as a double planet rather

than a planet and a moon.