HOMEWORK 7- Hand in at the beginning of class on Wednesday December 6th

• Write your answers on a regular 8.5"x11" paper -
• PLEASE STAPLE TOGETHER.
• Don't forget your name!
• A single number or word on its own is not an answer. You must show HOW you came to your answer and give the units of quantities.

(1) TPs vs. JPs. We have compared the Terrestrial Planets and the Giant or Jovian Planets, but when we look at the 4 Giant Planets we can see that they can be paired into Jupiter and Saturn vs. Uranus and Neptune.

(a) List 3 similarities between each set - similarities shared by all 4 giant planets.

(b) List 3 ways in which the Uranus and Neptune as a pair, differ from the pairJupiter and Saturn.

(3) Jupiter's Great Red Spot rotates completely in six days.

(a) If the spot is circular (not quite true, but a reasonable approximation for this matter) and 20,000 km in diameter, what are the wind speeds at the outer edges of the storm? (Hints: Speed = distance/time. How far does does a cloud on the edge of the spot move in one rotation? )

(b) How do these speeds compare with winds in terrestrial hurricanes where wind speeds can be 120 mph?

(4) "Ship's Log star date 2099: We are making our final approach to Jupiter. The heat shields have been deployed and we are ready to enter the atmosphere". Describe what a crew of vessel (designed to with stand huge pressures and temperatures) would see at they descended into the atmosphere of Jupiter. (About 5-10 sentances)

(5) Giant Planet Meteorology. Why does Uranus' atmosphere show strong variations over the past few years, Neptune and Saturn have had moderate changes while Jupiter's atmosphere appears pretty much the same, year in and year out? Explain.

(6) EUROPA has 2 characteristic properties:

(i) Europa is a bright satellite with a highly reflective surface, and

(ii) Europa has virtually no impact craters visible on its surface.

(a) Give an explanation for each property.

(b) How are these two properties related?

(7) Making Models of Planetary Rings

(a) The rings of Saturn are about 70,000 kilometers across but only 20meters thick. Suppose you wanted to build a model of Saturn's rings out of a sheet of plastic that is 2 mm thick. To keep the proportions right, how large a sheet of plastic would you need to make the scale model realistic? Show your work.

(b) To model Uranus' thin rings, strings of spaghetti (or perhaps, strictly speaking, linguini) would be more appropriate than sheets of plastic. Uranus' rings are also only about 20 meters thick and extend around the planet in a thin ring at a radius of about 50,000 km. If you wanted to build a model of Uranus' ring using 2mm thick pasta - how long a piece of spaghetti would you need? Show your work.

(8) General Doomsday strides purposefully into the Oval Office. "Mr President, I have bad news: to an object named Chunk I will come very close to the Earth - a thousandth of an AU. Sir, this object is over 109 nanometers in diameter, and has a mass of over FIVE THOUSAND GRAMS! It's made of the same material as the Meteor Crater in Arizona. We urgently request, oh, about 15 billion dollars to prevent a catastrophe." The President turns to you, his Science Advisor, and asks

(a) "How big is this object in everyday terms? "

(b) "How close will it get?"

(c) "What is the worst that could happen?"

(d) "Should we worry and/or do anything?" Explain.