1
The Jovian Planets
●
Huge worlds, heavily mantled in gas at the time of the
formation of the Solar System.
2
The Galilean Satellites
●
Jupiter has four planetary-sized moons first seen by Galileo
and easily visible in binoculars.
3
The Galilean Satellites
●
Jupiter has four planetary-sized moons first seen by Galileo
and easily visible in binoculars.
4
Io and Geological Activity
●
Io, being similar in size to the Earth's Moon, might be
expected to be a geologically dead world.
5
Io and Geological Activity
●
It turns out to be the most volcanically active world in the
Solar System.
6
Io and Geological Activity
●
●
It turns out to be the
most volcanically active
world in the Solar
System.
–
No impact craters!
–
Coloration from Sulfur
and sulfur
compounds.
Density = 3.0 g/cm3
–
mostly rock
–
formed in a “warm
location”?
–
ices baked away?
7
8
9
10
Io's “Atmosphere”
●
The volcanic activity produces a continuously escaping
tenuous atmosphere of sulfur and sodium near Io, and a
“torus” of this material around Jupiter.
11
Heating Io Internally – Tidal Stretching
●
●
Io has an elliptical orbit due to tugs from the other large
Galilean satellites.
The solid body of Io experiences significant, regular tidal
distortion as a result (the orbit takes just under 2 days)
12
Heating Io Internally – Tidal Stretching
●
The tidal stretching heats the interior of Io significantly, so
much so that volcanism is rampant.
13
Europa and Tidal Heating
●
Europa is the next Galilean satellite out from Jupiter
●
Craters are rare on Europa as well
–
tidal heating is much weaker – greater distance / slower orbit
–
Europa, however has an icy surface – easier to melt.
14
Europa and Tidal Heating
●
Europa is the next Galilean satellite out from Jupiter
●
Craters are rare on Europa as well
–
tidal heating is much weaker – greater distance / slower orbit
–
Europa, however has an icy surface – easier to melt.
15
Europa and Tidal Heating
●
Europa also has a density close to 3.0 g/cc.
–
The outer layer of ice is the top of a true frozen-over “ocean”
about 100 kilometers deep.
–
Weak tidal heating combined with radioactive decay keep
Europa warm enough keep the ocean liquid below a few
kilometers of icy crust.
–
Liquid water in the outer solar system!!!
16
Europa and Tidal Heating
●
Europa also has a density close to 3.0 g/cc.
–
The outer layer of ice is the top of a true frozen-over “ocean”
about 100 kilometers deep.
–
Weak tidal heating combined with radioactive decay keep
Europa warm enough keep the ocean liquid below a few
kilometers of icy crust.
–
Liquid water in the outer solar system!!!
17
Europa as an Abode for Life
●
●
●
Europa's ocean is likely habitable if
life formed there.
Interestingly, it is now thought that
life on Earth may have originated
near submerged volcanic vents.
The most primitive life forms on Earth
thrive in extreme environments – e.g.
boiling water.
18
Europa as an Abode for Life
●
●
●
Europa's ocean is likely habitable if
life formed there.
Interestingly, it is now thought that
life on Earth may have originated
near submerged volcanic vents.
The most primitive life forms on Earth
thrive in extreme environments – e.g.
boiling water.
19
20
Enceladus
●
Tidal heating again?
–
21
http://www.planetary.org/blog/
22
http://www.planetary.org/blog/
23
Composition of the Jovian Planets
●
Jupiter and Saturn attracted so much gas gravitationally
during formation that the have a composition that largely
matches the Sun
–
Mostly hydrogen, some helium, and a a tiny fraction of the
other elements.
24
Composition of the Jovian Planets
●
Jupiter and Saturn attracted so much gas gravitationally
during formation that the have a composition that largely
matches the Sun
–
Mostly hydrogen, some helium, and a a tiny fraction of the
other elements.
- Uranus and Neptune
are also dominate by
Hydrogen and Helium,
but not to the degree
that Jupiter and Saturn
are.
- The significant portion
of their mass likely
made up by water leads
to Uranus and Neptune
being called “ice
giants”
25
The Galilean Satellites
●
Jupiter has four planetary-sized moons first seen by Galileo
and easily visible in binoculars.