Understanding the Phases of the Moon: A Lunar Simulator Exercise, Lecture notes of Astronomy

Download Understanding the Phases of the Moon: A Lunar Simulator Exercise and more Lecture notes Astronomy in PDF only on Docsity! Name: ___ Date: _________________ Period: LAB #46: The Phases of the Moon Part I (Background): Look at the Lunar Simulator (on the smartboard or the link on Mr. Lanik’s astronomy page on the website) to answer the following questions. Question 1: Which of the following statements is true? a) There is no such thing as a “dark side” of the moon. We can, over time, see the full surface of the moon. b) There is no such thing as a “dark side” of the moon. The whole moon is illuminated during a full moon. c) There is a “dark side” of the moon. It is the side that is perpetually in shadow. d) There is a “dark side” of the moon. It is the side of the moon that always points away from the earth. Question 2: What causes the phases of the moon? a) The earth’s shadow on the moon as it revolves around us. b) The fraction of the moon illuminated by the sun that we see changes as the moon revolves around us. c) Half of the moon is made of dark rock that doesn’t reflect light. As the moon rotates, we see more and less of the dark rock. d) The light from the sun reflects of the earth’s surface, and illuminates part of the moon as it revolves around the earth. Question 3: Correctly match the following words to their meanings. gibbous to increase in size, quantity, volume, intensity, etc. waning decrease in magnitude, importance, brilliancy, intensity, etc. waxing convex, rounded – also hunch-backed, having a hump Question 4: The moon a) rises in the east and sets in the west. b) rises in the west and sets in the east. c) rises in the south and sets in the north. d) doesn’t “rise” and “set” per se, it is always visible in an observer’s sky but can only be seen at night when the bright sun doesn’t obscure its presence. Question 5: When viewed from above the North Celestial Pole, the moon a) orbits counterclockwise at a rate slower then the earth spins b) orbits counterclockwise at a rate faster than the earth spins c) orbits clockwise at a rate slower then the earth spins d) orbits clockwise at a rate faster than the earth spins Part II (Using the Simulator): The items below will help familiarize yourself with the controls and usability features of the simulator. If you have not already done so, launch the Lunar Phase Simulator (link is on “Astronomy Page”) The main panel has sunlight, the earth, and moon. The earth and moon can be dragged with the mouse. Below the main panel, there are animation controls. The moon and earth can be dragged, even while animating. The increment buttons move both the moon and earth by the specified time. The Moon Phase panel shows the current moon phase. Drop down menus will jump to a predefined position. Note that the phases, such as crescent and gibbous, are more broad than the particular point chosen by the presets. The Horizon Diagram panel displays the point of view of the observer (and you are second observer looking down on that observer). The observer globe can be dragged around for convenience. The sun and moon on the globe can be dragged around. In the Diagram Options panel, the show angle option shows the earth-moon-sun angle. The phases are technically defined in terms of this angle. It is there for convenience/interest only. In the Diagram Options panel, the show lunar landmark option draws a point of reference to more easily observer lunar rotation and revolution. In the Diagram Options panel, the show time tickmarks option displays the time of day of the observer. Earth – Moon – Sun This section explores the earth-sun-moon geometry and relationship. The items below are specific activities to perform to help you understand and answer the questions in this section. Hide the content of the Moon Phase panel and the Horizon Diagram panel by clicking on the hide button in those panels. Click on the moon or earth and drag them around or watch them animate. Observer how they rotate and which way the rotate. Increment the time by day, hour, and minute. Observe how the earth and moon change position with respect to each other. Carefully observe the moon graphic as it moves around the earth. The moon is also spinning around its own axis of rotation. Use the lunar landmark if desired. Question 6: As viewed from the simulator (above the earth’s North Pole), which direction does the moon rotate, clockwise or counterclockwise? Which direction does the earth rotate? moon: earth: Question 7: If the simulator time is incremented by one day, why doesn’t the earth appear to move with respect to the sun in the simulator, but the moon does? ____________________________________________________________________________________________ ____________________________________________________________________________________________ Question 8: At all times, how much of the moon’s entire surface is lit by sunlight? When the moon is opposite of the sun, how much of the shadowed part of the moon is visible? ____________________________________________________________________________________________ ____________________________________________________________________________________________ Question 9: How many times does the moon rotate around its own axis in the time it takes the moon to make one (sidereal) revolution around the earth? (you can use the ESRT p.15 for this!) ____________________________________________________________________________________________ ____________________________________________________________________________________________ Question 10: In the figure below, bisect the moon twice. a) Bisect with a line to show the half of the entire moon that is illuminated (and shade the shadowed region if desired). b) Bisect with a line to show the half of the moon visible from an observer on earth. c) Mark the region that is both visible from earth and illuminated by the sun. That region will be the phase of the moon we on earth see.