Transcript Moons Jupiter was known to have at least 16 moons at the time this

Moons
Jupiter was known
to have at least 16
moons at the time this
textbook was written.
Most of them have
synchronous orbits.
There are four Galilean
moons which are about the
size of Earth’s moon.
From closest to the planet
to farthest they are:
Io, Europa, Ganymede,
and Callisto.
Within the orbit
of Io there are
four smaller
moons.
Beyond Callisto there are
eight smaller moons.
The inner four of these
eight have eccentric,
inclined orbits. The outer
four are fairly eccentric
and retrograde.
The four small inner moons
Amalthea, the third moon
Thebe, the fourth moon
Each group probably
represents a single
body that was broken
apart into the smaller
moons that are
present today.
Io - the densest,
most geologically
active object in
the solar system.
Voyager 1 found eight
erupting volcanoes.
Voyager 2 passed by
four months later and
found that six of the
eight were still erupting.
Io’s surface is
exceptionally smooth,
any cracks are filled
in by molten lava.
It has a thin
atmosphere of SO2.
Io’s volcanic activity
produces the Io Plasma
Torus, a donut-shaped
region of energetic
heavy-ions that follows
Io’s orbital track.
The Io plasma
torus encircles
Jupiter and has
lethal radiation
levels.
The source of Io’s energy
is Jupiter’s pull of gravity.
It pulls more on the part of
Io that is close to Jupiter
and less on the part further
away.
Europa’s gravitational
pull on Io causes Io’s
orbit to be noncircular and nonsynchronous.
This difference in
pull causes internal
upheavals in Io and this
friction produces the
excess energy that
causes the volcanic
activity.
Europa - Networks of
crisscrossing lines over
bright clear fields of
water ice. The lines
may be cracks in the
ice. Europa has few
craters.
Ganymede & Callisto Both have much ice
throughout. Ganymede
is the largest moon in
the solar system. It is
larger than the planets
Mercury and Pluto.
Ganymede has many
impact craters (maybe
even highlands and
maria). It also has
grooves and ridges.
Callisto has a series
of concentric ridges
surrounding two
large basins.
Callisto
Valhalla
impact
crater
Callisto
Scarp
Jupiter has rings.
They are not as
large or prominent
as those of Saturn.
They were
discovered by the
Voyager missions,
but were predicted by
many astronomers.
Shoemaker-Levy 9 impacts
G impact projected on Earth