i. The sun is not moving; the parent position of the sun is changing because the Earth is changing.II. Phases of the Moon: What causes them?a. Helps to think in 3Db. Sun light is coming at Earth, the moon goes around the Earthi. What determines phase of moon1. Where it is in its orbit at any given timea. If moon is between sun and earth, face of moon that’s lit is away from us.i. The moon is dark (new moon)ii. As moon moves in its orbit1. “First quarter” left side of moon is lit.a. The right side of moon is always lit because that is where the sun is.iii. Full moon: we see entire portion of the moon that’s lit.iv. Third quarter: standing on Earth looking at moon, the left side of the moon is litc. It takes one week for each change in quarter of the moon phased. We always see the same face on the moon.ASTRON 89 1nd Edition Lecture 5 Outline of Last Lecture I. The Celestial Sphere II. Measuring Angles in the SkyIII. Reason for Seasons IV. Equinoxes and Solstices Outline of Current Lecture I. Seasons: Concept Check II. Phases of the Moon: What causes them? Current LectureI. Seasons: Concept Checka. If Earth’s axis was up and down, and not tilted, the North Pole would not have periods of time where it would not see the suni. There would mainly be no seasons. Every place on Earth would have 12 hours of day and 12 hours of night, no cold spell and no warm spellb. How long does sun take to move from being next to being bright star all the way around celestial field and back to that same bright star?i. The sun is not moving; the parent position of the sun is changing because the Earth is changing. 1. The sun is changing in the sky because it’s rising and setting (alongwith nearby stars) relative to the Earth; their actual position in space does not change literallyii. Because the Earth changes, the sun seems to “move away” from that bright stariii. Over the course of the year – the sun “comes back” to the seeming star inspace with the same bright star behind it. Answer is 1 yearc. How often each year does an observer standing on Earth’s equator experience noshadow during the noontime Sun? (Someone stands on equator does not see a shadow, meaning the Sun is DIRECTLY OVERHEAD)i. Answer is twice. WHY?These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.1. Only when the equinoxes occur, a point on the equator will have the sun directly overheada. 2 times a year 2. For places on Earth that are between the tropics, the sun is directly overhead twice a yeara. Between the solstice and neighboring equinox it is a quarter of a year, so 3 months or approximately 91 daysII. Phases of the Moon: What causes them? a. Helps to think in 3Db. Sun light is coming at Earth, the moon goes around the Earthi. What determines phase of moon1. Where it is in its orbit at any given time a. If moon is between sun and earth, face of moon that’s lit isaway from us. i. The moon is dark (new moon) ii. As moon moves in its orbit 1. “First quarter” left side of moon is lit. a. The right side of moon is always lit because that is where the sun is. iii. Full moon: we see entire portion of the moon that’s lit. iv. Third quarter: standing on Earth looking at moon, the left side of the moon is litc. It takes one week for each change in quarter of the moon phase d. We always see the same face on the