Astronomy 150 – Midterm Name:November 2, 2006 – Autumn 2006 TA’s Name & Section (2 pts):Answer all questions in the space provided. If you have any questions, raise your hand.100 points possible. No calculators.1 (6 pts) How do we determine the age of the lava flow from the Apollo 12 landin g site?2 (6 pts) How do we determine the age of the lava flow on the floor of the Tsiolkovsky crater on the f ar sideof the Moon.3 (3 pts) Iridium is a siderophile (i.e., iron-loving) element. Explain why Iridium is very rare in the crustof the present-day Earth.You have discovered a new planet orbiting the Sun at a distance of 0.7 AU. This planet is one-half (1/2)the size of the Earth, and is one-twelve (1/12) as massive. The planet has an uncompressed density of 3.8g/cm3and a moment-of-inertia factor of 0.34. (Use this information to answer the questions on the nexttwo pages).4 (6 p ts) How does the gravity of th is planet compare to the Earth’s gravity? [Be quantitative; show yourwork.]5 (4 pts) What is the most likely composition of this planet? [Remember to give a qualitative indication ofthe amount of each substance.]6 (2 pts) How is the mass distributed in the interior?7 (8 pts) Explain why it is unlikely that this planet has a thick atmosphere today.8 (6 pts) Would you expect the geological activity on this world to be greater or less than the currentgeological activity of the Earth? Explain your answer.9 (4 pts) On the left is an image of a thin section of a rockfrom the surface of this planet. Based on the lunar sampleimages you looked at in lab, what type of rock is it? (checkone) Basalt Breccia Regolith Pristine Highland Rock10 (8 pts) A self proclaimed expert on this planet has claimed that the age of the rock above to be 10million years old. Explain why 10 million years old is most likely not the correct age for this rock, and giveyour estimate on how old the rock would likely be.11 (8 pts) Explain why rock samples collected on the surface of the Moon tend to get older as you approachan impact crater.12 (8 pts) The Mars Exploration Rovers have found lots of evidence that some parts of the surface of Marswere wet in the past. I kept s aying that this implies that the atmosphere of Mars was different in the past.Explain how it was different and why it needed to be.13 (5 pts) Th e plot above shows the crater density plot of an Apollo landing site. Based on this data, tellme if this landing site was a highland or mare landing site. Be sure to explain your answer.14 (5 pts) On the plot above, sketch and label a line that shows the crater dens ity for the other type oflanding site (Highland or Mare).15 (5 pts) On the plot above, sketch and label a line that shows the crater density of a young surface of aworld with a thick atmosphere.ABCDEFAge: 10 MyrAge: 19 MyrAge: 25 MyrAge: 29 MyrAge: 35 MyrAge: 13 MyrOn the left is a drawing of a piece of the surface of a world in the inner solarsystem showing a system of shield volcanoes (A-F). The numbers indicate theages of volcanoes (in millions of years). Use the data in this drawing to answerthe questions on this page.16 (8 pts) Based on this data, would you assume that this world has plate tectonics? Explain your answer.17 (6 pts) Explain why the ages of these volcanic regions were probably not determined by crater counting,even if that the world’s atmosphere has little effect on the crater pop
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