Jason Kendall

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Lunar Phases and the Various Months

In this video, I chat about the lunar phases, what they are, and how they come about. I define the various kinds of months and show how they differ. Then, I'm also talking about SuperMoons, Micromoons, Harvest Moons, and Blue Moons. So many moons. Also, there's a tiny bit about the upcoming total solar eclipse on April 8, 2024! This is part of my complete intro Astronomy class that I taught at Willam Paterson University and CUNY Hunter. • Moon’s Rotation and Revolution: The moon rotates on its axis at the same rate it revolves around the Earth, which is why we only see one side of it. • Phases of the Moon: The moon goes through a cycle of phases, from waxing crescent to full moon to waning crescent, due to its changing position relative to the Earth and Sun. • New Moon Phase: The new moon occurs when the moon is in the same direction in the sky as the sun. • Moon Phases Explanation: The Moon’s phases are caused by its position relative to the Earth and Sun, with the illuminated portion visible from Earth changing as the Moon orbits. • Moon’s Rotation and Revolution: The Moon rotates on its axis at the same rate it revolves around the Earth, which is why we always see the same side of the Moon. • Visualizing Moon’s Rotation: The red line representing the Moon’s axis of rotation demonstrates that the Moon rotates 360 degrees as it revolves around the Earth. • Tidal Locking Explanation: The Moon’s rotation and revolution periods are synchronized due to tidal locking, causing the same side to always face Earth. • Moon’s Formation and Distance: The Moon was closer to Earth and spinning faster during its formation, gradually moving farther away and slowing its rotation over time. • Month Definition Review: A sidereal month is based on the Moon’s position relative to distant stars, while a solar month is based on its position relative to the Sun. • Sidereal Month: The time it takes for the Moon to complete one revolution around the Earth relative to distant stars, approximately 27.3 days. • Synodic Month: The time interval between successive alignments of the Moon and Sun from an Earth observer’s perspective, approximately 29.5 days. • Zodiacal Conjunction: When the Sun, Earth, and Moon are aligned in a straight line, resulting in a new moon or full moon. • Moon Phase Visualization: Using diagrams to illustrate the Moon’s phases, including the waxing crescent, and how the illuminated portion changes from Earth’s perspective. • Far Side vs. Near Side of the Moon: Explanation of the Moon’s far side, which is never visible from Earth, and the near side, which is illuminated by the Sun. Overall, the segment emphasizes clear definitions, underlying geometry, and practical observing guidance so viewers can connect the concept to the real sky.