Ast 281 Review for Exam 1 – Tuesday, February 25, 2014 – in class The Exam will be a CLOSED BOOK exam, lasting the whole period. You will be allowed to have calculators and the sheet of planetary data, but I doubt that you will need either of them. The exam will consist of the following types of questions: • 15 True / False (2 points each; 30 points total) • 15 Multiple Choice (3 points each; 45 points total) • Short answer questions (total of 75 points) • My exams tend to be fairly long, so answer what you can first and then go back to the more dif ficult things. Don’t write too much on any one question, but write enough to get your point across. Single word answers on the essays will not be good enough! Likewise, don’t justify T/F or multiple choice questions. The exam will cover all material up through our last lecture. The ex am is intended to test how well you understand the concepts, so in general I don’t expect you to spend time furiously memorizing all the little details we have discussed. A good way to study would be to read through the lecture notes again and be sure you really understand all the con cepts. Also, as you study each lecture, ask yourself the highlevel question of what were the 23 big important concepts from that lecture. This is what I do when I make the exam, and I write my questions based on that. I will often introduce you to a new situation on the exam and ex pect you to use your understanding of the material to figure out the answer (I love transporting you to alien worlds...). Useful review topics: • You should know the order of the EM spectrum (gamma rays to radio), and the approximate wavelengths. This is important when you are looking at a transmission spectrum graph so you know if the gas absorbs in the IR for example, for a greenhouse effect. – Understand the interaction of EM radiation and matter: when do we get a continuous spectrum, absorption and emission. – How do we get remote compositional information from space? – Know the difference between the Greenhouse effect and the ozone problem – Understand the basics of the structure of the atom, and the differences between differ ent isotopes. Understand why atoms are unstable and how we can use this to date ma terials. – How important is the presence and chemical make up of an atmosphere on a planet to the planet’s surface temperature, to climate and habitability? • How would you define life, and do we need a definition? – What are the characteristics of Earth life and how does this translate to requirements for a habitable world that could support life? – What is meant by biological evolution; how this relates to our search for life elsewhere? – What is special about water that makes it useful for life • What are the basic steps that had to occur in the origin of life? – Which ones do we think we understand – Which steps were the hardest – How have we traced the history of life on Earth?
Transcript
Ast 281 Review for Exam 1 – Tuesday, February 25, 2014 – in class The Exam will be a CLOSED BOOK exam, lasting the whole period. You will be allowed to have calculators and the sheet of planetary data, but I doubt that you will need either of them. The exam will consist of the following types of questions:
My exams tend to be fairly long, so answer what you can first and then go back to the more dif-‐ficult things. Don’t write too much on any one question, but write enough to get your point across. Single word answers on the essays will not be good enough! Likewise, don’t justify T/F or multiple choice questions. The exam will cover all material up through our last lecture. The ex-‐am is intended to test how well you understand the concepts, so in general I don’t expect you to spend time furiously memorizing all the little details we have discussed. A good way to study would be to read through the lecture notes again and be sure you really understand all the con-‐cepts. Also, as you study each lecture, ask yourself the high-‐level question of what were the 2-‐3 big important concepts from that lecture. This is what I do when I make the exam, and I write my questions based on that. I will often introduce you to a new situation on the exam and ex-‐pect you to use your understanding of the material to figure out the answer (I love transporting you to alien worlds...). Useful review topics: • You should know the order of the EM spectrum (gamma rays to radio), and the approximate
wavelengths. This is important when you are looking at a transmission spectrum graph so you know if the gas absorbs in the IR for example, for a greenhouse effect. – Understand the interaction of EM radiation and matter: when do we get a continuous
spectrum, absorption and emission. – How do we get remote compositional information from space? – Know the difference between the Greenhouse effect and the ozone problem – Understand the basics of the structure of the atom, and the differences between differ-‐
ent isotopes. Understand why atoms are unstable and how we can use this to date ma-‐terials.
– How important is the presence and chemical make up of an atmosphere on a planet to the planet’s surface temperature, to climate and habitability?
• How would you define life, and do we need a definition?
– What are the characteristics of Earth life and how does this translate to requirements for a habitable world that could support life?
– What is meant by biological evolution; how this relates to our search for life elsewhere? – What is special about water that makes it useful for life
• What are the basic steps that had to occur in the origin of life?
– Which ones do we think we understand – Which steps were the hardest – How have we traced the history of life on Earth?
– What are conditions that are good for the origin of life?
• What are the basic steps that had to occur in the origin of life? – Which ones do we think we understand – Which steps were the hardest – How have we traced the history of life on Earth? – What are conditions that are good for the origin of life?
• What are the basic classification (group names) for extremophiles (in terms of Temperature
and other extreme conditions). – How do microbes make a living – what is metabolism? Where do they get energy? – What sort of environmental variables can affect the energy availability? – Are there any type of environments that would be totally inhospitable to life?
• Understand the types of exogenic/endogenic processes and how we can use them to infer
characteristics about the interior and properties of worlds we can only observe remotely. – Why are tectonic and volcanic processes important for habitability? – Do we see similar processes on all planets and large moons in the solar system? – What drives plate tectonics? – What is volcanism? What influences what type of volcanism we have? – What are the types of exogenic processes?
• Understand the basic structure of Earth’s atmosphere – including the altitudes at which the
temperatures change and what causes the temperature increases at specific altitudes. – How is this different for other terrestrial planets? – What is scale height and how does this depend on Temperature, planet mass and at-‐
mospheric composition? – Which planets have atmospheres, and how were they created? How does this affect the
planet’s evolution? – How has Earth’s atmosphere and surface changed throughout time and why?
• What were the 4 major time divisions in Earth’s history (and approximate years)
– What was Earth like during each of these periods (and how do we know the infor-‐mation)?
– What big event occurred in each of these time periods? – Where did Earth possibly get its ocean water – Be familiar with the concept of radioactive dating, and why you would use one material
over another for dating
• What are comets and why are they important to study from an astrobiology context? – What physical process is occurring when a comet develops a tail? – What big event occurred in each of these time periods?
Sample Exam Questions: 1. Which of the following statements regarding life’s biochemistry is NOT true?
(a) The elements CHON account for the majority of biomass of life on earth (b) The elements CHON are among the most abundant within the universe (c) Water is the most abundant volatile molecule within the cosmos (d) Amino acids are produced in significant quantity throughout the universe (i.e.
by nonbiological processes) (e) Nucleic acids are produced in significant quantity throughout the universe
(i.e. by nonbiological processes) 2. Which of the following provided definitive proof of plate tectonics on Earth?
(a) apparent fitting together of the coastlines of continents (b) similarity of plant and animal species from continent to continent (c) paleomagnetic measurements (frozen magnetic field in rocks) (d) the lack of a runaway greenhouse (e) all of the above
3. Why doesn’t the Deep Impact Mission carry explosives to make the crater?
(a) public concern over launching weapons (b) comets are made of such dense material that explosives would be ineffective (c) not necessary because the energy from the impactor mass and velocity is suf-‐
ficient 4. What type of spectra are shown at
the right? (a) emission (b) absorption (c) blackbody only
5. What is the source (or sources) of
Earth’s atmosphere? (a) Comet impacts (b) Volcanic outgassing (c) accretion of gases in planetesimals (d) gravitational capture of gases from the solar nebula (e) all of the above
6. Which of the following statements is true?
(a) Water and Carbon are required for life (b) Life is made of the most abundant cosmic elements (c) Only living systems can replicate (d) Earth is exceptional because it has water (e) All of the above
7. Why might silicon be a possible alternative to Carbon? (a) It has the same atomic mass (b) It is common in the atmosphere (c) It can bond with 4 different atoms like carbon (d) It is more abundant than carbon (e) B+C
8. Sort the following from earliest (closest to Earth’s formation) to latest (closest to
9. Why was it so difficult to find Precambrian fossils?
(a) Nobody cared about the origins of life (b) No life existed in the Pre-‐Cambrian (c) Hard to distinguish early life from geological formations (d) The organisms had soft bodies and biology recycled organics (e) C+D
10. Which of the following factors control the extent of a planetary atmosphere?
(a) temperature (distance to the sun) (b) mass of planet (gravity) (c) composition of the atmosphere (d) all of the above (e) (a) and (b) only
11. A terrestrial body the size of Mercury would lose its internal heat through:
(a) Convection (b) Conduction (c) Hot spot volcanism (d) (b) and (c) (e) (a), (b), and (c)
12. Finish the following sentence by filling in the blanks (a) and (b) with the options be-‐
low: Plate tectonics (a) currently unique to Earth & (b) important for creating a hab-‐itable environment
(a) (a) is; (b) is not (b) (a) is; (b) is (c) (a) is not; (b) is (d) (a) is not; (b) is not
Sample Discussion Questions:
1. What makes water a good solvent for life? What are the minimum requirements for life? What are amino acids for and where did they come from before life started?
2. A lone volcano which is five times the size of Mt. Everest is observed during your exploration of a planet in a distant galaxy. What can you tell about the planet from the endogenic signature you observe? What is your reasoning?
3. Given the table of planetary properties for a group of planets around antother star similar to our Sun. The TCalculate represents the equilibrium temperature of a body at that distance from the sun with the albedo given. The TMeas is the measured temperature either at the “surface” of the planet, or in the case of a gas giant, at a depth in the atmosphere where the pressure is 1 atm. (1 bar).
a. Which of the following planets likely have atmospheres and why? b. Which ones might be habitable and why?
4. The pictures at the left show various planetary landscapes. Which of the features are endogenic, or exogenic. What can these images tell us about the potential for habitability on these worlds?
