The Jovian Planets

1
The Jovian Planets

• The Gas Monsters.

2
Jupiter
3
Size of 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 (318
  times Earth).

Orbit 778,330,000 km (5.20 AU) from Sun
Diameter 142,984 km (equatorial) Mass
1.900e27 kg
4
Mythology

• Jupiter (a.k.a. Jove Greek Zeus) was the King
  of the Gods, the ruler of Olympus and the patron
  of the Roman state.Zeus was the son of Cronus
  (Saturn).

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Composition

• The gas planets do not have solid surfaces, their
  gaseous material simply gets denser with depth.

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Composition

• Jupiter is about 90 hydrogen and 10 helium with
  traces of methane, water, ammonia and "rock".

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• Jupiter and the other gas planets have high
  velocity winds which are confined in wide bands
  of latitude.
• The winds blow in opposite directions in
  adjacent bands.
• Slight chemical and temperature differences
  between these bands are responsible for the
  colored bands that dominate the planet's
  appearance.
• The light colored bands are called zones the
  dark ones belts.

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Atmospheric Belts and Zones
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Atmosphere

• The interior heat of Jupiter probably causes
  convection deep within Jupiter's liquid layers
  and is probably responsible for the complex
  motions we see in the cloud tops.

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Voyager Space Craft

• The voyager space crafts have given us much of
  the information we know about Jupiter and Saturn

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Clouds and Spots
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The Great Red Spot
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GRS

• The Great Red Spot (GRS) has been observed from
  Earth for more than 300 years

The GRS is an oval about 12,000 by 25,000 km,
big enough to hold two Earths. Other smaller but
similar spots have been known for decades.
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Interior of Jupiter
15
Metallic Hydrogen?
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IMPACT!

• In July 1994, Comet Shoemaker-Levy 9 collided
  with Jupiter with spectacular results

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Jupiter has rings like Saturn's, but much fainter
and smaller (right). They were totally unexpected
and were only discovered when two of the Voyager
1 scientists insisted that after traveling 1
billion km it was at least worth a quick look to
see if any rings might be present
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Moons

• Galileo's discovery, in 1610, of Jupiter's four
  large moons Io, Europa, Ganymede and Callisto,
  are now known as the Galilean moons).
• Jupiter has 16 known satellites, the four large
  Galilean moons and 12 small ones

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Saturn
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Mythology

• In Roman mythology, Saturn is the god of
  agriculture.
• The associated Greek god, Coronus, was the son of
  Uranus and Gaiaand the father of Zeus (Jupiter).
  
• Saturn is the root of the English word "Saturday"

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Mass, Size, and Distance

• M 6.58 x 1026 kg
• Diameter 119,000 km equatorial and 107,000
  polar.
• Distance to sun 9.52 AU or 1,426,000,000 km

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Orbit

• Saturns orbit is almost spherical.
• The planet is inclined about 27 degrees from
  vertical.

23
Composition

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

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Saturns Interior
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Saturns Rings
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Ring Composition

• The rings are actually composed of innumerable
  small particles each in anindependent orbit.
• They range in size from a centimeter or so to
  several meters.
• A few kilometer-sized objects are also likely.

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Close-up of rings
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Moons15!
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Titan

• Second largest moon in the Solar System

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• TITAN IS THE ONLY MOON TO HAVE A KNOWN ATMOSPHERE

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Uranus
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Mythology

• Uranus is the ancient Greek deity of the Heavens,
  the earliest supreme god.

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Size, Mass, Distance

• orbit 2,870,990,000 km (19.218 AU) from Sun
• diameter 51,118 km (equatorial)
• mass 8.683 x 1025 kg

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Uranus from Earth
Uranus was the first planet discovered in modern
times (March 13, 1781).
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Composition

• Uranus is composed primarily of rock and various
  ices, with only about 15 hydrogen and a little
  helium (in contrast to Jupiter and Saturn which
  are mostly hydrogen).
• Uranus (and Neptune) are in many ways similar to
  the cores of Jupiter and Saturn minus the massive
  liquid metallic hydrogen envelope.
• It appears that Uranus does not have a rocky core
  like Jupiter and Saturn but rather that its
  material is more or less uniformly distributed.

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Atmosphere

• Uranus' atmosphere is about 83 hydrogen, 15
  helium and 2 methane.

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Rotation of 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.
• At the time of Voyager 2's passage, Uranus' south
  pole was pointed almost directly at the Sun.
• This results in the odd fact that Uranus polar
  regions receive more energy input from the Sun
  than do its equatorial regions.

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Rings

• Like the other gas planets, Uranus has rings.
• Like Jupiter's, they are very dark but like
  Saturn's they are composed of fairly large
  particles ranging up to 10 meters in diameter in
  addition to fine dust.
• There are 11 known rings, all very faint the
  brightest is known as the Epsilon ring.

39
Moons

• Uranus has 20 named moons plus 1 recently
  discovered one which as yet has not been given an
  official name.
• Unlike the other bodies in the solar system which
  have names from classical mythology, Uranus'
  moons take their names from the writings of
  Shakespeare and Pope.

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Neptune
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Mythology

• In Roman mythology Neptune (Greek Poseidon) was
  the god of the Sea.

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Discovery of Neptune

• After the discovery of Uranus, it was noticed
  that its orbit was not as it should be in
  accordance with Newton's laws. It was therefore
  predicted that another more distant planet must
  be perturbing Uranus' orbit.Neptune was first
  observed by Galle and d'Arrest on 1846 Sept 23
  very near to the locations independently
  predicted by Adams and Le Verrier from
  calculations based on the observed positions of
  Jupiter, Saturn and Uranus.

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Orbit, Mass, Diameter

• orbit 4,504,000,000 km (30.06 AU) from
  Sundiameter 49,532 km (equatorial)mass
  1.0247e26 kg

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Composition

• Neptune's composition is probably similar to
  Uranus' various "ices" and rock with about 15
  hydrogen and a little helium.
• Like Uranus, but unlike Jupiter and Saturn, it
  may not have a distinct internal layering but
  rather to be more or less uniform in composition.
  But there is most likely a small core (about the
  mass of the Earth) of rocky material.
• Its atmosphere is mostly hydrogen and helium with
  a small amount of methane.

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Atmosphere

• Like a typical gas planet, Neptune has rapid
  winds confined to bands of latitude and large
  stormsor vortices.Neptune's winds arethe
  fastest in thesolar system, reaching2000
  km/hour.

46
Rings

• Neptune also has rings. Earth-based observations
  showed only faint arcs instead of complete rings,
  butVoyager 2's imagesshowed them to becomplete
  rings with bright clumps.

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Because Pluto's orbit is so eccentric, it
sometimes crosses the orbit of Neptune making
Neptune the mostdistant planet from the Sun for
a few years.
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Moons

• Neptune has 8 known moons 7 small ones and
  Triton.

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Pluto
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Mythology

• In Roman mythology, Pluto (Greek Hades) is the
  god of the underworld. The planet received this
  name (after many other suggestions) perhaps
  because it's so far from the Sun that it is in
  perpetual darkness and perhaps because "PL" are
  the initials of Percival Lowell.
• Lowell predicted the existence of Pluto

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Pluto was discovered in 1930 by a fortunate
accident. Calculations which later turned out to
be in error had predicted a planet beyond
Neptune, based on the motions of Uranus and
Neptune. Not knowing of the error, Clyde W.
Tombaugh at LowellObservatory inArizona did a
verycareful sky survey which turnedup Pluto
anyway.
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Mass, Size, Distance

• orbit 5,913,520,000 km (39.5 AU) from the Sun
  (average)
• diameter 2274 km
• mass 1.27 x 1022 kg

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Orbit
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.
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PLUTO FROM EARTH BASED TELESCOPE
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Composition

• Pluto's composition is unknown, but its density
  (about 2 gm/cm3) indicates that it is probably a
  mixture of 70 rock and 30 water ice much like
  Triton.
• The bright areas of the surface seem to be
  covered with ices of nitrogen with smaller
  amounts of (solid) methane, ethane and carbon
  monoxide.

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Moons

• Fortunately, Pluto has a satellite, Charon.
• By good fortune, Charon was discovered (in 1978)
  just before its orbital plane moved edge-on
  toward the inner solar system.
• It was therefore possible to observe many
  transits of Pluto over Charon and vice versa. By
  carefully calculating which portions of which
  body would be covered at what times, and watching
  brightness curves, astronomers were able to
  construct a rough map of light and dark areas on
  both bodies.

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Pluto and Charon from HST