Transcript Document

Chapter 7 : Mentos
Chapter 7
The Jovian Planets
Units of Chapter 7
Observations of Jupiter and Saturn
The Discoveries of Uranus and Neptune
Bulk Properties of the Jovian Planets
Jupiter’s Atmosphere
The Atmospheres of the Outer Jovian Worlds
Jovian Interiors
Summary of Chapter 7
7.1 Observations of Jupiter and Saturn
Jupiter can be imaged well from Earth, even
with a small telescope.
Here: Jupiter with its Galilean moons
True-color image of Jupiter
Natural-color image of Saturn
Cassini image of
Jupiter, true color
7.2 The Discoveries of Uranus and
Neptune
Uranus, in
natural
color.
Note the
absence of
features.
Neptune in
natural color
7.3 Bulk Properties of the Jovian
Planets
The Jovian planets are large and much less
dense than the terrestrial planets; Saturn is less
dense than water!
Jovian planets, compared to Earth
Peculiarity of Uranus: Axis of rotation lies
almost in the plane of its orbit. Seasonal
variations are extreme.
7.4 Jupiter’s Atmosphere
Atmosphere has bright
zones and dark belts.
Zones are cooler, and
are higher than belts.
Stable flow underlies
zones and bands, called
zonal flow.
Simplified model:
No solid surface;
take top of
troposphere to be 0
km.
Lowest cloud layer
cannot be seen by
optical telescopes.
Measurements by
Galileo probe show
high wind speeds
even at great depth
– probably due to
heating from planet,
not from Sun.
The Galileo
probe
descended
into Jupiter’s
atmosphere
and returned
valuable data.
The arrow
indicates its
entry point.
Major visible features:
Bands of clouds; Great Red Spot
Two examples of
smaller storms
merging, first into
a smaller red spot,
second into existing
Great Red Spot
7.5 The Atmospheres of the Outer
Jovian Worlds
The atmosphere of Saturn is
similar to that of Jupiter, except
that Saturn is somewhat colder
and its atmosphere is thicker.
Saturn’s
atmosphere is
similar to
Jupiter’s,
except
pressure is
lower.
It has three
cloud layers.
Cloud layers
are thicker than
Jupiter’s; see
only top layer.
Saturn also has large storms, and bands.
Storms near Saturn’s equator
Enormous
thunderstorm
on Saturn
Rotation of Uranus can
be measured by
watching storms.
Neptune has
storm
systems
similar to
those on
Jupiter, but
fewer. The
large storm
system at
top has
disappeared
in recent
years.
7.6 Jovian Interiors
No direct information is available about Jupiter’s
interior, but its main components, hydrogen and
helium, are quite well understood. The central
portion is thought to be a rocky core.
Magnetic fields of Uranus and Neptune must not
be produced by dynamos, as the other planets’
fields are.
Interior structure of Uranus and Neptune,
compared to that of Jupiter and Saturn:
Jupiter’s
magnetosphere:
Intrinsic field
strength is 20,000
times that of Earth.
Magnetosphere can
extend beyond the
orbit of Saturn.
Aurorae are seen
on Jupiter, and
have the same
cause as those
on Earth – the
interaction of
solar wind
particles with the
magnetosphere.
Uranus and Neptune both have substantial
magnetic fields, but at a large angle to their
rotation axes.
The rectangle
within each planet
shows a bar
magnet that would
produce a similar
field. Note that
both Uranus’s and
Neptune’s are
significantly off
center.
How do we know what the internal
structures of the Jovian planets are like?
A. Probes have been sent into the
interiors of the planets and have
returned data about the conditions.
B. Astronomers use the Earth's internal
structure as a basis of comparison.
C. Astronomers examine the composition
of the satellites of these planets.
D. Astronomers use information about the
physical characteristics as well as laws
of physics to obtain theoretical models.
Which of the following statements is
FALSE?
A. Interior heating in the Jovian planets
contribute to convection in the
atmospheres.
B. Slow rotation rates lead to very
strong coriolis forces.
C. The circulation patterns tend to be in
very elongated bands that encircle the
planets.
D. The circulation speeds increase
towards the equator.
Near the core of Jupiter, hydrogen is
A.
B.
C.
D.
E.
a low temperature gas.
a high temperature gas.
a solid.
a liquid.
a liquid metal.
The great red spot of Jupiter is thought
to be
A.
B.
C.
D.
caused by an enormous volcano.
a region of hotter gases.
a long-lasting cyclonic storm.
an opening through the high level
clouds revealing a portion of the
atmosphere nearer the surface.
Which of the following are true about
Jupiter's belts (dark) and zones(light)
A. belts are rising while zones are
sinking.
B. belts are sinking while zones are
rising.
C. both belts and zones are rising.
D. both belts and zones are sinking.
Jupiter's magnetic field probably
originates
A. in the liquid metallic hydrogen
region.
B. from the solar wind.
C. in the vicinity of Io.
D. from the motion of the
Galilean satellites.
Compared to Earth, the expected
seasonal changes on Uranus because
of its orbital and spin-axis alignments
will be
A. much less.
B. very much exaggerated.
C. absent, because of the alignment
of the spin axis.
D. the same .
From the results of the voyager 2
mission of Uranus, we now know that
the
A. planet has fewer rings than
expected.
B. magnetic field has a large tilt to the
spin axis.
C. larger moons have smooth surfaces
and little evolution.
D. rings are made of objects hundreds
of meters in radius.
Since Uranus has a higher average
density than Saturn
A. it must rotate faster.
B. it must have much more rocky
material.
C. it must have a stronger magnetic
field.
D. it must have a higher concentration
of icy materials.
Summary of Chapter 7
• Jupiter and Saturn were known to the
ancients; Uranus was discovered by chance,
and Neptune was predicted from anomalies in
the orbit of Uranus.
• Jovian planets are large but not dense; they
are fluid and display differential rotation.
• Cloud layers have light zones and dark bands;
wind pattern, called zonal flow, is stable.
Summary of Chapter 7, cont.
• Storms appear with regularity; the Great Red
Spot of Jupiter has lasted for hundreds of years
(that we know of).
• Due to conductive interiors and rapid rotation,
Jovian planets have large magnetic fields.
• Jupiter, Saturn, and Neptune radiate more
energy than they receive from the Sun.