STUDY SHEET FOR MIDTERM EXAM 2, ASTR305V, November 13, 2018

The 2nd midterm is on Chapters 5, through the first half of Chapter 11. Specifically, extra-solar planets, which is the 2nd half of Chapter 11 is NOT included. The section that is included of Chapter 10 and 11 includes the habitable zone and the properties of sun and stars, not the actual search techniques for exo-planets. Questions on Chapters 5 and 6 will be limited to a few main topics, as indicated below under each Chapter.

The test will be about 20 questions, with multiple choice and short written answers required. You do not need a scantron. Test answers are to be written on the exam sheets. Please contact me with any questions. (rwalterb@nmsu.edu)

To study, use lecture notes on web pages for the main points and follow up study from sections in the book. Depending on your background and familiarity with science in general and astronomy in particular, you may need to spend more or less time studying the book. The list below lists most of the major topics we have discussed. I may have missed one or two but the notes will make that clear.

Chapters 5 and 6

• Biological evolution, Darwin

• The role of natural selection

• The role of mutations

• Which aspects of biological evolution are "random", which are not?

• The cosmic calendar, and the most important major events in it

• The approximate time line of life on Earth, e.g. when did first complex life forms appear?

• When were some major mass extinctions, what were the possible origins

• Extremophiles

• What is the evidence for the earliest life on Earth, how far back does it go?

Chapters 7-9

• What are the most likely places outside Earth in solar system to find life?

• What is a tidal force? Where do they play a role? What relevance to life might they have?

• Differences between Earth and Venus, and Earth and Mars.

• Which planet has the largest greenhouse effect, which the least?

• A comparison of Mars' and Earth's atmospheres

• Besides sunlight, what are some other potential energy (heat) source(s) for planets

• What are the relevant properties of terrestrial planets in context of likelihood of life

• Space exploration: robotic missions versus manned missions (advantages and risks and relative cost of each)

• Telescopes and most important properties of them

• Various methods for space exploration: differences between fly-by's, orbiting space craft, landers, and return missions

• Where are we looking for life? Why?

• Why is Mars one of the most likely places to host or have hosted life?

• Which moons in the solar system might host life? Why?

• Why are these moons possibly still suitable even though they are so far away from the Sun?

Chapter 10 and first half of 11

• What is meant with the concept of "habitable zone"? How is it defined?

• Which properties decide where the habitable zone might be located for a particular star?

• Can all stars shine equally long? If not, why not? What is the most important property of a star which decides this?

• Which type of stars are hot, which type are cool?

• Which stars can life long, which stars will never live long?

• Which stars are faint in luminosity, which are bright?

• How does that affect the location of the habitable zone?

• What are the possible end phases of star of different mass?

• What determines the average temperature on a planet? Consider:
     properties of star
     distance from star
     presence of absence of greenhouse effect

A few example questions: these are examples. The examples given do NOT cover all the topics, they are examples only.

1. What is the main source of oxygen in the Earth's atmosphere?

a. oxygen is produced by photosynthesis in plants

b. oxygen has been present in the atmosphere since the formation of earth.

c. oxygen is liberated from the dissociation of water in the oceans.

d. oxygen is continuously created from the impacts of comets

2. For a star that is more massive and hotter than the Sun, the habitable zone will likely be:

a. About the same distance from that star as we are from the Sun.

b. Closer to the star than we are from the Sun.

c. Suitable to sustain life on a planet for much longer time than the Sun will be able to.

d. Further away from the star than we are from the Sun.

3. Which kind of star has the longest life time?

a. Stars like the Sun.

b. Stars with more mass than the Sun.

c. Stars with less mass than the Sun.

d. All stars have equal life times.

4. What is generally the lowest cost type of mission to another planet?

a. a lander

b. an orbiter

c. a fly-by

d. a manned mission

5. What is good about the Sun that helped create and sustain life on earth?

a. The sun emits a lot of ultraviolet light.

b. The sun is closer to the earth in the summer.

c. The sun has always been around.

d. The sun varies little in brightness over extended periods.

6. Why do we place telescopes in space? (At least two reasons).

7. The temperature of a planet in the solar system depends on its distance to the Sun, but also on some other important properties. Name at least one.

8. Describe one source of heat for planets or moons of planets that we discussed that does NOT depend on incoming sun light.

9. Give two reasons why Mars is a good planet to look for life in the solar system.

10. Consider biological evolution and the characteristics it may produce in species. Why do you think our eyes are best at seeing optical light and not the other kinds of light at other wavelengths?

11. Which planet in the solar system has the strongest greenhouse effect, which one the weakest?

12. What date of the year did the human species appear on Sagan's cosmic calendar? On what date did the dinosaurs go extinct?

13. True or false: Because the atmosphere on Mars is so tenuous, it does not produce a greenhouse effect