Astronomy Lecture Notes
Monday, November 19 2012 th
Jupiter’s Moon Io:
o Brilliant yellow, red, orang, black and white.
o No impact craters resurfaced by constant volcanic eruptions.
o Lave is rich in sulfur which changes color with temperature.
Io should have lost its heat but….
o Io orbits Jupiter, very large ass 00> strong tides
o In the large family of moon, which interact with each other
o Cannot synchronize its spin to its orbit.
o Tidal heating continues.
Slightly smaller than our moon – should be cold
Surface has almost no craters:
o Surface must be new.
Surface is water ice with many fractures.
o Tidal heating keeps water liquid below the ice.
o Crack allow water to flow to the surface and fills in craters.
Largest moon in the solar system… larger than diameter of mercury.
o Many craters less resurfacing.
o Dark zones with many craters and lighter regions with few craters.
o Has different ages
Craters revel water ice below the surface.
About the diameter of mercury.
Surface is heavily cratered
Recent craters reveal ice below.
Lessons from the Galilean Moons:
- As distances from Jupiter increase:
Surfaces have become more heavily cratered
Jupiter’s gravity becomes weaker
Less tidal stretching make satellites cooler and less active less
Tidal Heating (Europa) keeps water liquid even though sunlight = very faint.
Life might be possible far from the Sun.
Titan – Saturn’s Large Moon:
Like a planet: Astronomy Lecture Notes
Monday, November 19 2012th
o Diameter = larger than mercury.
o Mass = 40% of Mercury’s.
o Has an atmosphere.
90% N2 – recall Earth’s atmosphere