NATS 1311 From the Cosmos to Earth

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NATS 1311 From the Cosmos to Earth

Jovian planets compared to earth
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Jupiter and Io From 29 million miles
away. Zones- bright cloud regions, rising/
cooler gases. Belts- dark cloud regions,
descending / warmer gases. Heating from
interior causes cloud motions.

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NATS 1311 From the Cosmos to Earth
Jupiter Great red spot- Giant hurricane twice
the size of earth. False color image to enhance
cloud turbulence.

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NATS 1311 From the Cosmos to Earth
Jupiters ring (artists sketch) 35,000 miles
above cloud tops.

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Jupiters ring (Actual photo) 4000 miles, edge
to edge. 1 mile thick.

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NATS 1311 From the Cosmos to Earth FIG.9.4

Figure 9.4 These diagrams compare the interior
structures of the Jovian planets (shown
approximately to scale). All four planets have
cores equal to about 10 Earth masses or rock,
metal, and hydrogen compounds, and they differ
primarily in the hydrogen/helium layers that
surround the cores.
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NATS 1311 From the Cosmos to Earth FIG. 9.2

Figure 9.2 Jupiter's interior structure, labeled
with the pressure, temperature, and density at
various depths. Earth's interior structure is
shown to scale for comparison. Note that
Jupiter's core is only slightly larger than Earth
but is about 10 times more massive.
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NATS 1311 From the Cosmos to Earth

• SCIENTIFIC HIGHLIGHTS - JUPITER
• ATMOSPHERE
• CLOUD BANDS - ALTERNATE COLORS
• CLOUD MOTIONS -
• BELTS - REDDISH BROWN BANDS - COOLR
• ZONES - WHITE, YEEEOW BANDS - HOTTER
• COMPOSITION - WATER AND AMMONIA CLOUDS
• LIGHTNING AND AURORA OBSERVED
• GREAT RED SPOT
• HURRICANE STORM OVER 300 YEARS OLD
• TWICE THE DIAMETER OF EARTH
• RING
• 1 KM THICK, 6000 KM EXTENDED RADIALLY

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NATS 1311 From the Cosmos to Earth FIG.9.9
Figure 9.9 The larger satellites of the Jovian
planets, with sizes (but not distances) shown to
scale. Mercury, the Moon, and Pluto are included
for comparison.

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• GALILEAN MOONS
• Io
• 8 volcanoes
• Smooth young surface
• Sulfur and SO2 frost
• Volcanoes eject sulfur material producing a ring
  of sulfur and O2 around Jupiter
• Magnetic field of Jupiter allows particles to
  penetrate the polar regions, producing aurora

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NATS 1311 From the Cosmos to Earth FIG. 9.11
Figure 9.11 Io is the most volcanically active
body in the solar system. (a) An erupting
volcanic plume rising hundreds of kilometers
above Io's surface. (b) The reddish color of the
now-cooled lava flows extending from this volcano
on Io (center black dot) suggests they were once
molten sulfur. (c) This enhanced-color photo
shows fallout (dark patch) from a volcanic plume
on Io. The fallout region covers an area the size
of Arizona. (The orange ring is the fallout from
another volcano.)

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NATS 1311 From the Cosmos to Earth
Io Close-up of surface. Tidal heating causes
melting under surface to produce volcanoes.

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NATS 1311 From the Cosmos to Earth FIG. 9.12

Figure 9.12 Tidal heating explained. (a) Because
Io's orbit is slightly elliptical, the strength
and direction of Io's tidal bulges change. The
bulges and orbital eccentricity are exaggerated.
(b) About every seven Earth days (one Ganymede
orbit, two Europa orbits, and four Io orbits),
the three moons line up as shown. The small
gravitational tugs repeat and make all three
orbits slightly elliptical.
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• GALILEAN MOONS
• EUROPA
• Thin ice crust
• Fracture/ridge system
• Few craters

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NATS 1311 From the Cosmos to Earth FIG. 9.14

Figure 9.14 Europa is one of the most intriguing
moons in the solar system. (a) Europa's icy crust
is criss-crossed with cracks. (b) Some regions
show jumbled crust with icebergs, apparently
frozen in slush. This figure combines
low-resolution images and high-resolution
close-ups from the Galileo spacecraft. (c)
Close-up photos show that many surface cracks
have a double-ridged pattern.
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• GALILEAN MOONS
• GANYEMEDE
• Bright, young ray craters
• Impact basin
• Dark regions are heavily cratered
• Variety of geologic processes observed
• (e.g. crustal motion)
• Largest of the moons

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NATS 1311 From the Cosmos to Earth FIG. 9.15
Figure 9.15 Ganymede, the largest moon in the
solar system. (a) Ganymede's numerous craters
(bright spots) show that its surface is older
than Europa's (b) The brighter, ridged regions of
Ganymede's surface, called grooved terrain, have
few craters and indicate relatively recent
geological activity.

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• GALILEAN MOONS
• CALLISTO
• Ancient heavily cratered surface
• Impact basins
• Density low
• Little crustal motion

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NATS 1311 From the Cosmos to Earth FIG. 9.16

Figure 9.16 Callisto shows no evidence of
volcanic or tectonic activity. (a) Heavy
cratering indicates an ancient surface. (b)
Close-up photos show a dark powder overlying the
low areas of the surface.
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Callisto Large impact basin. Rings are shock
waves that froze quickly after impact.
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Saturn- Ring structure Tilt of rings 27 degrees
from orbital plane.
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Saturn Clouds- Belts and zones not as
pronounced as on Jupiter

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Saturn ring structure- false color image Cassini
division- large gap in rings
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NATS 1311 From the Cosmos to Earth FIG. 9.22

Figure 9.22 (a) The largest gap in Saturn's
rings, called the Cassini division, is caused by
an orbital resonance with the moon Mimas. (b)
Another Mimas resonance creates remarkable
ripples in Saturn's rings. The dark spots in the
image are calibration marks for the camera.
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Spokes in B ring Spokes do not follow Keplers
Laws Magnetic and electric fields form these
patterns.

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Another view of rings

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Titan, moon of Saturn 3200 miles
diameter Atmosphere denser than
earths. Nitrogen with some Methane. Temperatur
e on surface -180 deg. C.

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Comparison of earth and Titan atmospheres
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NATS 1311 From the Cosmos to Earth Fig. 9.17
Figure 9.17 Saturn's moon Titan. (a) Titan is
enshrouded by a hazy, cloudy atmosphere. (b)
Artist's conception of the surface of Titan,
showing the possible ethane oceans. (c) A recent
image from the Keck Telescope taken at infrared
wavelengths can see through Titan's clouds to the
surface. The dark areas may be oceans.

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• SCIENTIFIC HIGHLIGHTS - SATURN
• SATURN
• Atmosphere similar to Jupiter
• Dark belts and light zones
• High winds - 4 to 5 times faster than Jupiters
• Cold temperatures (90 k)
• Aurora
• Radio emissions
• RINGS
• Hundreds of ringlets
• F ring - 3 separate intertwined ringlets also
  clumps
• B ring has long radial spoke-like features

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• SATURNS SATELLITES
• 23 (9 major moons)
• Number 13 and 14 guard the f ring
• Number 15 is on the outer edge of the a-ring
• Titan
• Smaller than Ganymede, larger than Mercury
• Has a dense, hazy atmosphere of nitrogen
• (methane) and carbon dioxide with
• small concentrations of hydrocarbons
• Surface temperature is 100 k (-170c)
• Liquid nitrogen or methane lakes may exist at
• the poles

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True (left) and false colors images of
Uranus Picture of south pole from 9 million miles
away. South pole, pointed toward sun. Methane in
atmosphere absorbs red light hence blue
color. Discovered in 1781 by Wm. Herschel.
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Artists sketch of Uranus rings- discovered be
stellar occultation. Rings closer to planet than
moons.
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Ring structure Of Uranus. Shows dust in ring
system. Streaks are stars.

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Miranda, Moon of Uranus Cosmic museum Many
unique features. 7 Trapezoidal
region. Grooved terrain.

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Miranda Mountainous region.

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• SCIENTIFIC HIGHLIGHTS - URANUS
• Discovered by William Herschel in 1781
• 4 times earth's diameter
• First planet not known to Greek astronomers
• Blue-greenish appearance,with rocky core
• Thick hydrogen atmosphere with methane clouds
• Methane absorbes red light
• Rotation period 16.5 hours

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NATS 1311 From the Cosmos to Earth

• URANUS (continued)
• Spin axis tipped at 82 to the orbital plane
• Has a retrograde rotation
• Has a 21 year winter and a 21 year summer
• Poles have the same temperature
• Magnetic field is 50 times the earth's tipped 60
  degrees

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NATS 1311 From the Cosmos to Earth

• URANUS (continued)
• RINGS
• 10 rings
• 9 discovered by stellar occultation
• 1 discovered by Voyager spacecraft
• Probably composed of rocks rather than ice
• Source may have been a moon destroyed by a
  meteoroid
• impact

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NATS 1311 From the Cosmos to Earth

• URANUS (continued)
• MOONS
• 5 largest seen from earth made of rocks and ice
• 10 discovered by voyager spacecraft
• Mirandamany unique surface features,
• Chevron, grooved terrain, large valley, high
  cliffs

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Neptune Methane absorbs red light, gives
blue-green color. Great dark spot, like
Jupiters red spot. Cloud structure has belts
and zones, like Jupiter.

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Neptunes great dark spot. About size of
earth. Same relative size to planet as Jupiters
spot is to Jupiter. Atmosphere is very cold
-350F Scooter- cloud formation below the dark
spot.

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Neptunes rings 50,000 Km above planet. Clumpy,
not continuous. Probably methane ice.

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Triton, moon of Neptune. Probably a captured
asteroid. Polar cap, frozen nitrogen. Wrinkled
surface, like Mercury
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Close-up of Tritons surface . 70 rock 30
water ice. Very old craters. Circular region
may be volcano caldera.

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Tritons surface. The flat regions in this
close-up photo may be lava-filled impact basins
similar to the lunar maria.
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NATS 1311 From the Cosmos to Earth

• SCIENTIFIC HIGHLIGHTS - NEPTUNE
• Discovered in 1845 using mathematical analysis of
  Uranus' orbit
• Similar in size to Uranus, but slightly more
  dense
• Seeing Neptune is like seeing a dime a mile away
• Has a blue-green appearance (methane in
  atmosphere)
• Internal heating like Jupiter
• Great dark spot, not permanent
• Cloud features seen in atmosphere
• Cloud shadows indicate lower atmosphere is clear

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NATS 1311 From the Cosmos to Earth

• SCIENTIFIC HIGHLIGHTS - NEPTUNE
• RINGS
• Has a system of thin dark clumpy rings
• Two thin and two broad rings
• 50,000 and 60,000 km above planet
• Probably methane ice
• 8 MOONS
• 2 found from earth
• 6 discovered by voyager spacecraft

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• NEPTUNES MOONS
• Triton -
• Largest moon of Neptune
• Orbits Neptune in retrograde direction -
• probably a captured asteroid
• Slightly smaller than our moon
• Has a few craters in the southern region
• Has nitrogen frost at poles
• Atmosphere of nitrogen with traces of methane
• (much less dense than earth's)

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NATS 1311 From the Cosmos to Earth FIG. 9.23

Figure 9.23 Four ring systems. The planets are
not shown to scale. Uranus's rings were
photographed by the Hubble Space Telescope, the
others by Voyager. The Neptune frame is made of
two images, taken on either side of the bright
planet.
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NATS 1311 From the Cosmos to Earth .

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NATS 1311 From the Cosmos to Earth .

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NATS 1311 From the Cosmos to Earth .
The orientation of Pluto's spin axis and Charon's
orbit. Like Venus and Uranus, Pluto has its
rotation axis tipped over so far that it points
below the plane of the planet's orbit (which is
itself tipped by an unusually large angle, 17,
relative to the ecliptic). Thus the spin of the
planet is technically retrograde (i.e.,
backwards). Charon orbits in the equatorial plane
of the planet. During the late 1980s, the plane
of Charon's orbit was aligned with thePluto-Earth
direction so that Pluto and Charon alternately
passed in front of each other. Observations of
these repeated transit events provided a wealth
of information on the nature of both bodies and
the transient atmosphere of Pluto.

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NATS 1311 From the Cosmos to Earth .

• SCIENTIFIC HIGHLIGHTS - PLUTO
• Discovered in 1930 by Clyde Tombaugh at Lowell
• Observatory
• Not a planet that perturbs Uranus' orbit - too
  small
• Orbit has a 17º inclination to the ecliptic
• Elliptical orbit which passes inside the orbit of
• Neptune (November 1978 to may 2000)
• Rocky core with methane and water ices, also
  nitrogen ice on surface

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NATS 1311 From the Cosmos to Earth .

• SCIENTIFIC HIGHLIGHTS - PLUTO
• Tenuous atmosphere of nitrogen and methane
• May be an escaped moon of Neptune or may be one
  of
• group of icy/rocky bodies in the outer solar
  system.
• Some orbit the Jovian planets and one, Pluto,
  orbits
• the sun
• Moon
• Charon1978 discovery
• Synchronous rotation with Pluto
• Only 20,000 km from Pluto
• Half the size of Pluto
• 10 mass of Pluto

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NATS 1311 From the Cosmos to Earth .
PROPERTIES OF THE SUN Diameter 864,000
miles Volume 1 million times that of the
earth Mass 330,000 times mass of
earth Composition By mass By
volume Hydrogen 75 90 Helium 24
9 Other 1 1

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NATS 1311 From the Cosmos to Earth .
SUN
Surface temperature 5700 k (5400º
C) Color yellow Rotation period 25
days at the equator 33 days near
poles Apparent magnitude - 26.7 Absolute
magnitude 4.8

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LUMINOSITIES Luminosity r2T4 Apparent
magnitude Apparent brightness of a celestial
body based on a logarithmic scale of
luminosity. Magnitude scale 1 is 2.51 2 is
6.31 5 is 1001 Absolute magnitude Equivalent
to the apparent magnitude if star were placed
10 parsecs (32.6 light years) from sun.

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NATS 1311 From the Cosmos to Earth .
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NATS 1311 From the Cosmos to Earth .
REGIONS OF SUN Photosphere Bright
disk Chromosphere Thin, tenuous layer right
above photosphere, several thousand km
thick Corona Rarefied outer region of
sun's atmosphere, millions of km thick

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NATS 1311 From the Cosmos to Earth .

• FEATURES OF THE SUN
• Photosphere
• Granules
• Mottled texture of surface caused by
  convection of hot gases
• Gases flowing out - brighter areas
• Gases flowing in - darker areas

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NATS 1311 From the Cosmos to Earth FIG. 12.4
Figure 12.4 The basic structure of the Sun.

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NATS 1311 From the Cosmos to Earth FIG. 12.2
Figure 12.2 Gravitational equilibrium in the
Sun At each point inside, the pressure pushing
up balances the weight of the overlying layers.

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NATS 1311 From the Cosmos to Earth .

• FEATURES OF THE SUN
• Photosphere
• Granules
• Mottled texture of surface caused by
  convection of hot gases
• Gases flowing out - brighter areas
• Gases flowing in - darker areas
• Sun spots
• Dark areas - size of earth
• Average lifetime of 6 days
• Regions of strong magnetic field

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NATS 1311 From the Cosmos to Earth FIG. 12.3
Figure 12.3 This photo of the visible surface of
the Sun shows several dark sunspots.

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NATS 1311 From the Cosmos to Earth FIG. 12.17
Figure 12.17 (a) This graph shows how the
number of sunspots on the Sun changes with time.
Note the approximately 11-year cycle. (b) This
graph shows how the latitudes at which sunspot
groups appear tend to shift during a single
sunspot cycle.

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NATS 1311 From the Cosmos to Earth FIG. 12.10
Figure 12.10 Granulation of the photosphere is
evident in this photo of two sunspots. Each white
granule is the top of a rising column of hot gas.
At the darker lines between the granules, cooler
gas is descending below the photosphere.

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NATS 1311 From the Cosmos to Earth FIG. 12.13
Figure 12.13 Pairs of sunspots are connected by
tightly wound magnetic field lines.

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NATS 1311 From the Cosmos to Earth FIG. 12.18

Figure 12.18 The Sun rotates more quickly at its
equator than it does near its poles, a behavior
known as differential rotation. Because gas
circles the Sun faster at the solar equator, it
drags the Sun's north-south magnetic field lines
into a more twisted configuration. The magnetic
field lines linking pairs of sunspots, depicted
here as green and black blobs, trace out the
directions of these stretched and distorted field
lines.
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NATS 1311 From the Cosmos to Earth .

• Chromosphere
• Spicules
• Spiked nature of chromosphere
• Prominences
• Rosy tongues of gas up to 30,000 km high
• Chromospheric gases seen in corona
• Plages
• Bright areas near sunspot regions
• Hotter gases

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NATS 1311 From the Cosmos to Earth FIG. 12.14

Figure 12.14 This photo shows a large solar
prominence, many times the size of Earth, which
consists of glowing gas trapped by magnetic field
lines arching high above the surface of the Sun.
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NATS 1311 From the Cosmos to Earth .

• Flares
• Brighter areas in plages
• Emit radiation in x-ray band
• Disrupt radio communications
• Cause aurora
• Corona
• Solar wind
• Streaming electrons and ions originating from
• Corona regions called coronal holes.

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NATS 1311 From the Cosmos to Earth FIG. 12.16

Figure 12.16 An X-ray image of the Sun reveals
the corona Brighter regions of this image
correspond to regions of stronger X-ray emission.
(Because X rays do not penetrate Earth's
atmosphere, photos like this one must be taken
from space.)