“Life’s a journey, not a destination.” Aerosmith. HW2 will be handed back on Tuesday and solutions posted- no late homework after Tuesday. Test 1 on Thursday Sept. 28. Sample test and review posted now.

The Jovian Planets

Jupiter Jupiter.

Density is 1.3g/cc 318X Earth’s mass

Has rings

And many moons, including 4 big ones.

Io, the innermost Galilean moon

Europa's structure Ice crust Liquid ocean Rocky mantle Rocky (iron?) core. Density = 3.0 g/cc

Ganymede's interior ice crust. thick, water-ice layer (mostly frozen). rocky mantle an iron core. Density = 1.9 g/cc Extremely thin Oxygen atmosphere created by charged particles hitting the ice surface.

Callisto's surface is old and heavily cratered.

Callisto's structure Density = 1.9 g/cc Being the furthest moon from Jupiter and under the least tidal stress, Callisto did not have time to differentiate much before it became frozen. Density = 1.9 g/cc However, Callisto shows signs of a variable magnetic field, an indication of a subterranean, salty ocean.

Io < few million, Europa ~20-180 million years, Older & colder the farther away from Jupiter. Io < few million, Europa ~20-180 million years, Ganymede ~3 billion years, Callisto: 4-4.5 billion years old

Europa ~20-180 million years Structure changes as they get further from Jupiter. Surface Age: Io < few million Europa ~20-180 million years Ganymede ~3 billion years Callisto: 4-4.5 billion years old Density = 3.5 g/cc Density = 3.0 g/cc Density = 1.9 g/cc Density = 1.8 g/cc

Notice how prevalent water is in the solar system! Structure changes slightly as they get further from Jupiter. Notice how prevalent water is in the solar system! Europa, Callisto (liquid?) Ganymede, Moon, Mercury (ice)

Time to do HW2 Please put everything away except your homework and your clicker. Make sure your name and row letter are clearly written/typed on the top of your homework. Please, no talking, do your own work.

Question 1: How many stars are there in our solar system? B) 2 C) 3 D) 4 E) 0 F) More than 10

Question 2: Which type of erosion is occuring on Titan? A) Rain/lakes/rivers B) Choose answer A C) Really, choose answer A D) If you pick this one, you’re wrong.

Question 3: How are the outer moons different from our Moon? A) They are mostly made of gas. B) They have a LOT of water (ice crusts) C) They have more craters. D) They are mostly shaped like disks.

Question 4: Where does frozen exist on the Moon? A) At the equator B) At the poles, in craters where there is no direct sunlight. C) Only on the Earth-facing side. D) Only on the away-from-Earth-facing side. E) It is everywhere.

Question 5: What is the relationship between Mercury’s rotational period and orbital period? A) Nothing. They are not related. B) One side of Mercury always faces our Moon. C) One side of Mercury always faces the Sun. D) It is tidally locked to the Sun, but in a resonance, so 2 years is 3 spins.

Question 6: What is an appropriate observation for the image? A) It is fuzzy, so it is made of gas. B) It has a very smooth surface, so it is liquid on top. C) It has well-defined features, so it is a solid. D) It is one color, so made of one composition.

B) different- they each cratered during different periods. Question 7: For the terrestrial planets, we think the cratering histories (amount of cratering with time) are…. A) the same. B) different- they each cratered during different periods.

Question 8: Which has more impact craters? A) Io B) Callisto C) They are both the same. D) There is no way to tell.

Question 9: How do we determine the rotation period of gas planets? A) Using their magnetic fields. B) A sounds like a good answer. C) Yeah, I like answer A D) You should probably just click A and be done with it.

Question 10: The object in the picture ... A) is fuzzy, so it is made of gas. B) has a very smooth surface, so it is liquid on top. C) has well-defined features, so it is a solid. D) has many colors, so is made of many different compositions.

Question 11: What provides the heat for Io’s volcanoes? A) The Sun. B) Radioactive material trapped within Io. C) It is mostly on fire. D) Tidal forces from Jupiter.

Please pass it to your right. Turn in HW2 Make sure your name and row letter are clearly written/typed on the top of your homework. Please pass it to your right.

Jupiter also has lots of smaller, irregular moons.

Jupiter's irregular moons. In reality, these orbit in any direction. Many are captured asteroids.

Saturn

Infrared view

Saturn's structure is very similar to Jupiter's. Clouds which thicken to liquid Metallic hydrogen interior Rocky core Density = 0.7 less than water!

Solar day = 10 hours 40 minutes This spin is so fast that Saturn is visibly larger at the equator then the poles. 95 times more massive then Earth.

56 known moons

Saturn's rings.

Saturn's Rings. * Are extremely thin: 200,000km across, but typically about 200m thick! * Made of millions of particles- but not very thick! -1cm to 10m in diameter -mostly ice or ice-covered rocks - all the ring material, compressed into a rock would only be 100km across.

Saturn’s moon Titan. At 10AU from the Sun, the temperature in space is -290oF. Bigger than our Moon.

This is what Titan looks like using Hubble. Infrared view.

Infrared image. Just treat it like a black and white image.

Radar image: Treat it like a black-white picture. 130 miles across. Estimate surface age

Another radar image

300 miles across. My favorite!

8 Carefullly examine the area within the arrows. What is this feature and what does it mean to the object as a whole? Image is ~200 miles across.

Huygens optical picture while parachuting down. What are we looking at and what does it mean to the environment of this moon?

True color image from the surface.

*Titan is larger than Mercury and more massive than Pluto. *It has an extremely thick atmosphere. Composed mostly of N2 like Earth's but 50% thicker than ours. *94k (- 290F) at Titan's surface. *At it's distance from the Sun, Titan is at the triple point of ethane/methane

Round → massive Clearly defined features → solid surface Hazy edge/clouds → atmosphere

Surface age- 8Myrs to 3.5Gyrs. Radar image: Crater; there are few. Surface age- 8Myrs to 3.5Gyrs. Mountain range → plate tectonics!

Dark streaks are sand dunes → wind & weather River delta below → rain! But too cold for water. Still no craters!

Maybe 1 crater, Obvious rivers, could be lava channels too (but they’re not in this case). Smooth plain too.

This dark, smooth area is a lake. This is an island This is an island This is a river channel

This is a volcano: large round feature, small round top, lines from it are ‘lava’ channels. Cryovolcano

The top is a (dry at the time) lake bed The top is a (dry at the time) lake bed. Bottom are hills with river channels. This means there is rain!!!!

True color image from the surface. Look around the ‘rock’ in the middle- see how it has been washed out around it? Like flowing liquid. This is like ‘rocks’ in ‘sand’ but there is no rock, it is all made of water ice.

The blue things are lakes! 300 miles across. The blue things are lakes!

Titan is a round, massive, solid object surrounded by a thick, opaque atmosphere. The surface is incredibly young, indicating many erosive processes including plate tectonics (mountain ranges), rain (river channels), and volcanoes.

Titan.... the other Earth. It rains, it pours, it snows, it evaporates.There are volcanoes and plate tectonics, rivers and lakes, and few (49 estimated) craters.There's wind, sand dunes, river beds, and lots of erosion. On Earth, where you say ‘rock’ on Titan, you say ‘water ice’. On Earth, where you say ‘water’ on Titan you say ‘ethane/methane’.

A liquid region within the ice. Density = 1.88 g/cc A liquid region within the ice. Structure: Ice crust over liquid water over rocky crust over rocky core.

Look at all the water!