Review for Exam 1

1. Review for Exam 1

2. Review • Exam: 50 questions, mostly multiple choice • Exam conducted at Pollock Testing Center • Each student schedules the time for their exam sometime between 8am and 10pm • Bring pencils and student IDs; no calculators allowed • For testing center details: http://testing.psu.edu/Students/ • Study materials • review questions • slides from lectures • your notes • homeworks • clicker questions • animations at my web site

3. Lectures 2-3: Motions of the Earth and Sky • What evidence did Aristotle cite for a spherical earth? • What is the name of the point in the sky above the north pole? What star is near that point? • What is diurnal motion? What causes it? How does diurnal motion of stars appear from the north pole? The equator? • Why can we see a given constellation at night during only part of the year? • What is the ecliptic? How are the zodiac constellations different from other constellations? • What causes the seasons? What are the solstices and equinoxes? • How does the maximum height of the Sun in the sky change over the course of the year? How does it change with latitude? • What is precession? What is its period? How does it affect the way we see the sky? • What are the relative locations of the Earth, Sun, and Moon during each lunar phase?

4. Lectures 2-3: Motions of the Earth and Sky • If given 2 of these 3 – time of day, Moon's phase, position in the sky – how do you determine the 3rd? • How long does it take the Moon to orbit the Earth once? • What are opposition and conjunction? • What are solar and lunar eclipses? During which phases do they appear? Why don't they occur every month? What portion of the Earth can see each? • Why are solar eclipses more rare than lunar eclipses? How often does each occur? • What is parallax? Which model of the solar system was supported by its apparent absence? Why didn’t Aristotle see parallax? • Which model did each of the following prefer? Aristotle, Ptolemy Copernicus, Tycho, Galileo, Kepler • What is the difference between inferior and superior planets in how they appear in the sky? What is the origin of this distinction? • What is retrograde motion? How did Aristotle try to explain it? What is the true cause of it?

5. Lectures 4-5: Galileo, Tycho, Kepler, Newton • What did Galileo see with his telescope? • What was Tycho'snotable accomplishment? What was his preferred model for the solar system? • What are Kepler's laws? • What are Newton's Laws of Motion? • What does the force of gravity depend on? What does the gravitational acceleration of an object depend on? • Why do we feel weight? In what circumstances does weightlessness occur? • Why doesn't the Earth fall into the Sun?

6. Lecture 6: Light • How are the wavelength, frequency, speed, and energy of light related? • What are the names of the different wavelength ranges of light? What is their order in order of wavelength, frequency, etc.? • Which wavelengths are able to penetrate the atmosphere and reach the Earth’s surface? • What is the Doppler shift? • What is the inverse square law of light? • Why is the sky blue? • How do peak wavelength and total energy of a blackbody depend on temperature? • What are the 3 kinds of spectra? What type of light source produces each one? • How are emission and absorption lines produced? • What kind of spectrum does the Sun produce?

7. Lecture 7: Telescopes • How are the sizes of telescopes characterized? What is meant by a “1 meter” telescope? • What are the 2 kinds of telescopes? Which one is used in modern telescopes? Why? • Why are telescopes with larger lenses or mirrors more powerful? What is the size of the largest optical and infrared telescopes? • Why are some telescopes put in space rather than on the earth? • What are some of the best locations on the Earth for telescopes? • What are the names of the major space observatories? In what wavelength ranges do they operate?

8. Lecture 8: The Sun and Moon • How long does it take light to travel from the center of the Sun to its surface? • What are aurorae? What kind of spectra do they produce? • What is a tidal force? • How does the tidal force of the Moon affect the Earth? • How has the tidal force of the Earth affected the Moon? • How do the rotational and orbital periods of the Moon compare? • What’s the difference between the far side and the dark side of the Moon? When are they the same? • How can you determine if you experience a low tide or high tide based on the time of day and phase of the Moon? During which phases of the Moon are the tides most extreme? • What are the 4 theories for the formation of the Moon? Which one do we believe is correct? Why?

9. Lecture 9: The Planets • What is the order of the planets with distance from the Sun? • Which planet has the highest surface temperature? largest mass? largest tilt of its spin axis? largest temperature variations? rotates backwards? polar ice caps? • How many moons does Mercury have? Venus? Mars? • Which planets have rings? • Which planets have no atmosphere? • Which moon has a thick atmosphere? • Which 3 factors determine if a planet holds onto an atmosphere? • What is the primary reason why Venus is much hotter than Earth?