Starry Night-Phases of the Moon and Misconceptions ..., Exams of Astrophysics

Download Starry Night-Phases of the Moon and Misconceptions ... and more Exams Astrophysics in PDF only on Docsity! 40 Starry Night-Phases of the Moon and Misconceptions Laboratory 6 Objective: In this laboratory you will take a close look at the lunar phase cycle. We will also explore some common everyday statements about the moon and its phases, to see if they are correct. Background: Moon Phases As the moon revolves around the earth, its position relative to the earth and sun changes. As a result, we on earth view the disk of the moon illuminated by different amounts resulting in what we call phases of the moon. The four main phases of the Moon are New Moon (NM), First Quarter (FQ), Full Moon (FM), and Last Quarter (LQ). Each of these phases of the Moon will occur at the same position relative to the Sun, and therefore each of them rises and sets at the same time each month. The approximate times are as follows: NM– rises around 6am, sets around 6pm FQ – rises around 12pm (noon), sets around 12am (midnight) FM – rises around 6pm, sets around 6am LQ – rises around 12am, sets around 12pm The moon sets approximately 50 minutes later each night. Moon Phase Diagram 41 Fraction of Illumination The fraction of the Moon that we see from Earth is called the fraction of illumination, sometimes noted as a percentage. The fraction of illumination for the phases of the Moon is as follows: Phase Fraction of Illumination New Moon 0% Waxing Crescent Between 0% and 50% First Quarter 50% Waxing Gibbous Between 50% and 100% Full Moon 100% Waning Gibbous Between 100% and 50% Last Quarter 50% Waning Crescent Between 50% and 0% There are 7 to 8 days between the new moon and the first quarter, first quarter and full moon, full moon and last quarter, and the last quarter and new moon. On the days in between are crescent and gibbous phases, with the lit potion of the lunar disk getting larger during the “waxing” phases, and smaller during the “waning” phases. The lunar phase cycle is approximately 29.5 days. Instructions: Statement #1: "The sun comes out during the day and the moon comes out at night." The first part of this statement concerning the sun must be true, as the Sun being above our horizon defines “daytime”. But the night is not defined by the moon, the night is defined by the absence of the Sun. So, is the moon always out when the Sun is not? Is the moon ever above our horizon during the day? Could we actually see the moon during the day if we knew where to look? 44 Statement #3: "The phase of the moon seen depends on where you are on the Earth." When looking at the moon phase diagram it is reasonable to think that the moon phases correspond to different locations on the Earth. But is that how it works? Would a different location on the Earth have a different viewpoint from another? Would that be enough to change the appearance of the phases? Let’s find out. To explore using Starry Night-From L.A., Ca. with time stopped, set the date to 3 hours after the Full Moon rises in January, 2011 (found in your table) and look at the Moon on your screen. Now go to New York by changing your viewing location and look at the moon again. This is accomplished by clicking the triangle located to the right of your current viewing location toward the top of your screen. Open the menu and select Other and then choose the proper location from the list. Click on the location and then click on Go To Location. Next go to Dublin, Ireland and Apatity, Russia and look at the moon again. (Just change locations, the time and date will change automatically to account for time zones.) 45 Write down the date and time at which the Moon is viewed from each location. Record the phase of the moon. Los Angeles- New York- Dublin- Apatity- At which locations is the moon phase the same? At which locations is it different? 46 Answer Sheet-Lab 6 Name- 1. Date Rise Time Set Time Phase Age Jan 4, 2011 at 11am Jan 7, 2011 at 2pm Jan 11, 2011 at 5pm Jan 14, 2011 at 8pm Jan 19, 2011 at 11pm Jan 23, 2011 at 11pm Jan 26, 2011 at 5am Jan 29, 2011 at 8am Feb 2, 2011 at 11am 2. What is the age and phase of the Moon on this date when it rises? Age-__________________ Phase-___________________ What is the age and phase of the Moon on this date when it sets? Age-__________________ Phase-___________________ Is there a noticeable change in what the Moon looks like? Does the phase of the moon depend on the time of day?