Cosmology II

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Cosmology II Powered By Docstoc
  Jupiter
  Saturn, its rings
     and moons
  Uranus
  Neptune
  Dwarf planets
Jovian – Jupiter like Planets

   Four outer planets
   Known as the ‘gas giants’
    o Two are ‘liquid giants’
    o Two are ‘ice giants’
   Each has rings
   Each has many moons
Great Red Spot
Great Red Spot
White ovals within the bands
Weather on Jupiter
Jupiter’s Interior
Jupiter’s Interior
Comet impact,
July 1994
Jupiter’s Ring

  This image was taken by the Galileo
   satellite with Jupiter in shadow
Enhanced color image of
the halo around the ring

 Ring particles are micron-sized (cig. smoke)
 The ring is formed from particles released
  from satellites due to micro-impacts
 Particles continually fall into the ring on the
  outer edge and into Jupiter on the inner edge
to scale
  Io
  Europa

  Ganymede
  Callisto
     Moons of Jupiter
Io         Europa   Ganymede       Callisto

       Ganymede, the largest moon in the solar
        system, is 8% larger than Mercury and is
        52% larger than the Moon
Ganymede – largest moon

  a) Enhanced color
  b) True color, showing evidence of water
  Density 1.9g/cm3, mix of rock and ice
Callisto close-up

  Callisto has
 a mineral-rich
 liquid water ocean
 under its surface
  These craters
 show the clean ice
 underneath the
 dirty surface.
             Density 1.79g/cm3, 50:50 rock to ice

 Density
of 3g/cm3,
mostly rock,
with an icy
 Notice the
cracks, which
help indicate a
liquid ocean underneath
Cracked, icy crust of Europa
 The color is brown, due to the minerals
  dissolved in the liquid water beneath the 100
  km thick icy crust

  Most volcanically
 active object in the
 solar system, ~100
 active volcanoes
  Density
 3.55g/cm3, no ice,
 just metals
 and rock
Size of
the rings
Geology of the rings

  Cassini’s division is caused by resonance
in the
in size
Thinness of the rings

  The plane of the rings is only about a
   dozen meters thick
Shepherd satellites keep
dust in this and the next ring
 Without the moons, there would be no
  rings around any planet
Saturn’s Interior
Saturn’s Moons
53 Named moons and over 150 ‘moonlets’

  IR
 There is
  liquid water
  the surface
 A geyser on
  the south
  pole is
  emitting water
  into space,
  adding to the E ring
  and recovering the surface
Enceladus’ geyser
Enhanced views
of Enceladus’
Quiz Time!
1 Jupiter reveals all of
the following except
A.   Auroras and lightning.
B.   A powerful magnetic field.
C.   Radiation belts of solar wind particles.
D.   A solid surface beneath the clouds.
2 Jupiter’s ineterior:

A.   Is mostly molten magma.
B.   Is mostly liquid hydrogen.
C.   Is mostly gas.
D.   Is mostly ice.
3 Jupiter’s Great Red Spot
A.   A large volcano on Jupiter’s surface.
B.   Evidence of life on Jupiter.
C.   A cyclonic storm.
D.   One of Jupiter’s polar caps.
4 Jupiter’s four Galilean
moons are:
A.   Zeus, Jove, Eros, and Appalonia.
B.   Io, Europa, Ganymede, and Callisto.
C.   Micky, Minnie, Goofy, and Doc.
D.   Castello, Eros, Ganymede, and Io.
5 Jupiter’s moon Io has:

A.   Lots of Geysers.
B.   Nothing but ice covering it.
C.   Methane oceans.
D.   Lots of Volcanoes.
6 What theory was
advanced to explain the
origin of Saturn's rings?
A. Another planet wandered too close, invaded
   the Roche limit, and broke up.
B. Saturn captured material from the Asteroid
C. Comets collided with and broke up small
   satellites that formed with the planet.
D. They are basically the same today as they
   were when they first formed with Saturn.
7 Saturn’s rings:

A.   Are unique; only Saturn has rings.
B.   Two planets have rings, Saturn and one other.
C.   Four planet have rings.
D.   All planets have some sort of rings.
8 The thickness of
Saturn’s rings is:
A.   A few meters.
B.   A couple of miles.
C.   Hundreds of kilometers.
D.   Close to 10% of an AU.
9 Saturn’s has:

A.   No moons, just rings.
B.   Only shepard moons; they keep the rings together.
C.   Four moons.
D.   More than 100 moons.
10 Saturn’s moon
A.   Shoots lightning at Saturn.
B.   Has volcanoes that shoot rocks.
C.   Is dormant and quiet.
D.   Has a giant geyser that rains ice.
 Uranus’ rings –          found when
 occulting a star, in 1977

 Notice the eccentricity of the ε ring,
  probably due to the eccentricity of its
  shepherd moons, Ophelia and Cordelia
 These rings have
an albedo of 0.015,
   darker than coal
  • There is almost
       no dust, just
  Uranus’ moon Ariel
 Perhaps these
  canyons were
  cut by flowing
 (1160 km)
  Uranus’ moon Miranda
 Notice both the
  deep gauging
  and the round
  sunken sections,
  possibly due to
  convection as
  the moon was
 (485 km)
image of
(The spot
  is no longer
Neptune is
  4% smaller
  than Uranus.
Neptune’s seasons
Neptune’s seasons
Neptune’s rings      aren’t
complete, but have voids
They are much dustier than Uranus’
There aren’t enough
particles to complete
the circles of the rings
in Neptune.
                            moon Triton
                            (78% Earth’s Moon)

Nitrogen frost polar cap
(above) and a basin
showing signs of flooding
Planetary Line-up

   by Lynette Cook, picture used by permission
Planetary Line-up

   by Lynette Cook, picture used by permission
    Planetary Revolutionary
     Periods and Distances
   Mercury – 0.24 yrs – 0.387 AU
   Venus – 0.62 yrs – 0.723 AU
   Earth – 1 yr – 1 AU
   Mars – 1.88 yrs – 1.52 AU
   Jupiter – 11.87 yrs – 5.20 AU
   Saturn – 29.46 yrs – 9.54 AU
   Uranus – 84.01 yrs – 19.2 AU
   Neptune – 164.79 yrs – 30.1 AU
The Definition of a planet

 A "planet" is defined as a celestial body that:

 1. Is in orbit around the Sun
 2. Has sufficient mass for its self-gravity to
    assumes a nearly round shape
 3. Has cleared the neighborhood around its
Dwarf Planet Candidates
 Pluto and its three moons

Hydra and
Charon’s orbit

  Charon, Pluto’s
   largest moon is about
   51% of its size, but
   only 1/12 the mass
Dwarf Planets and the
Kuiper Belt
   The Kuiper Belt is a region of perhaps
    70,000 asteroid-like part rock, part icy
    bodies close to Neptune’s orbit.
   About 1000 have been found, to date.
    Eris is so far the largest (about 5%
    larger), followed by Pluto, then Sedna
    and Orcus (~65% Pluto’s size), then
    Quaoar (~50%)
   With Ceres (in the asteroid belt), these
    are the dwarf planets.
Plutinos and the Kuiper Belt

   The Kuiper belt dwarf planets are in
    different resonances with Neptune
   Pluto and the ~ 100 other, smaller
    Plutinos are in a 3:2 resonance. (For
    every 2 orbits of Plutinos, Neptune has 3
    orbits. This is why Pluto will never hit
    Neptune, even though it crosses
    Neptune’s orbit.) Other objects have
    many other resonances (2:1, 4:3, etc).

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