AST 301Exam # 2 Study Guide Lectures: 5-10Lecture 5 (September 23)Introduction to Lunar GeologyDescribe some geological characteristics of the moon?The moon has low density, meaning no large iron core. The moon also has no global B-field, thus no molten core. However, it does have a fossil B field meaning there once was a molten core early on. The moon has no molten or plastic asthenosphere due to the absence of major moonquakes. Small moonquakes that were observed were probably the result of tidal stress and strain. The moon also cools quicker than the Earth because of a thick lithosphere and no plates.What are the theories of the origin of the moon? Explain.The fission theory was that the moon fissioned from the Earth like a “child.” The co-accretion theory says the moon formed simultaneously as the Earth like a “sibling.” There is also the capture theory that the moon is a capture of an object formed elsewhere. The giant impact theory is currently the best model, which believes that the moon was formed because of a collision with a Mars-sized object early on.Lecture 6 (September 25)Explain Bode’s LawThe Titius-Bode Law is rough rule that predicts the spacing of the planets in the Solar System. The relationship was first pointed out by Johann Titius in 1766 and was formulated as a mathematical expression by J.E. Bode in 1778. It lead Bode to predict the existence of another planet between Mars and Jupiter in what we now recognize as the asteroid belt. It relates the mean distance of the planets from the Sun to simple mathematical progression of numbers.List some facts about the Solar SystemThe Sun has most of the mass. The orbits of the planets lie roughly in the same plane. The rotational equator of the Sun is nearly in this plane, the orbital plane of the planets. Planetary orbits are nearly circular. Most planets revolve around the Sun in prograde sense-the same direction the Sun rotates, west to East.Lecture 7 (September 30)What are some facts about Mars?Mars’ orbital period is 687 Earth days. Its atmosphere consists mostly of carbon dioxide and occasionally the temperature will read 80 F. The summer has permanent water ice caps and the winter has large carbon dioxide “dry ice” caps.Lecture 8 (October 2)What are some facts about Jupiter?Since Jupiter is farther from the Sun, it is colder and thus harder for the atmospheric gas to escape. Jupiter itself is twice as massive as all the other planets combined. Jupiter is nearly a star as it radiates more energy than it receives. One orbital period takes 11.9 years. Jupiter has more than 60 moons, and counting. Its’ B-field is 20-30 times that of Earth’s.Describe the 3 groups of the Moons of Jupiter?Jupiter’s moons are classified into 3 groups: outer, middle, and inner moons. Outer moons are formed close to the Sun and captured, 50/50 rock and ice. They have eccentric orbits and large inclinations. The middle moons are also eccentric and are highly inclined. They are possibly also captured with the same composition. The inner moons were probably formed with Jupiter and have circular orbits.Lecture 9 (October 7)What are some facts about Saturn?Saturn’s density is so low that it would float in a bathtub. Its’ orbital period is about 29.4 years. It has 18 relatively large moons and its B-field is 2/3 of Earth’s field at the equator. Its’ extensive complex rings are large icy particles from boulders, down to the size of dust in a room.Briefly describe Saturn’s moons.Saturn’s main moon is Titan among others. The other moons fall into 2 groups. One are small and rocklike, but very little is known about these moons. The second group is intermediate between Galilean and smaller moons of Jupiter. They have low density and lots of water
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