Motion of the Moon

Motion of the Moon

1.5 Motion of the Moon

• The Moon takes approximately 29.5 days to complete a full cycle of phases; this is known as a synodic month.
• The phases of the Moon are determined by the relative positions of the Moon, the Sun, and the Earth.
• The time it takes for the Moon to make a full 360° orbit around the Earth, known as a sidereal month, is about 2 days shorter than a synodic month.

1.5 Motion of the Moon

• When the right side of the Moon is illuminated, it is in a waxing phase.
• When the right side of the Moon is in darkness, it is in a waning phase.
• It is essential to know the phases of the Moon for quizzes and exams.

Moon Phases

• New Moon
• Waxing Crescent
• First Quarter
• Waxing Gibbous
• Full Moon
• Waning Gibbous
• Third Quarter
• Waning Crescent

1.5 Motion of the Moon

• Eclipses occur when the Earth, Moon, and Sun align in a straight line.
• The diagram illustrates favorable and unfavorable conditions for eclipses, showing the relative positions of the Earth, Moon, and Sun.
• A solar eclipse is seen when the Moon's shadow falls on the Earth.
• A lunar eclipse is seen when the Earth's shadow falls on the Moon.
• The Moon's orbit is inclined at an angle of 5.2° relative to the Earth's orbit, which affects eclipse visibility.

1.5 Motion of the Moon: Lunar Eclipse

• A lunar eclipse occurs when the Earth is positioned between the Moon and the Sun.
• A partial lunar eclipse happens when only a portion of the Moon passes through the Earth's shadow.
• A total lunar eclipse occurs when the entire Moon is within the Earth's shadow.

1.5 Motion of the Moon: Solar Eclipse

• A solar eclipse occurs when the Moon is positioned between the Earth and the Sun.
• A partial solar eclipse occurs when the Moon blocks only a fraction of the Sun's disk.
• A total solar eclipse occurs when the Moon completely blocks the Sun's disk.
• An annular solar eclipse happens when the Moon is farther from the Earth, and thus appears smaller, leaving a ring of sunlight visible around the Moon's silhouette.

1.5 Motion of the Moon

• Eclipses do not occur every month because the Earth's and Moon's orbits are not in the same plane.

Determining Moon Rise Times

• The graphic illustrates the positions of the Moon during its phases relative to the Earth's rotation and the Sun's light.
• Positions include New Moon (not visible), Waxing Crescent (1), First Quarter (2), Waxing Gibbous (3), Full Moon (4), Waning Gibbous (5), Waning Crescent (6).
• The diagram correlates the Moon's phase with the time of day: Noon, Sunset, Midnight, Sunrise.
• Waxing crescent is 1-4 days old, waxing gibbous is 3-10 days old.

Transit Time Question

• What time does the first quarter moon transit?
  • The correct answer is not explicitly provided in the visible text.

Set Time Question

• What time does the first quarter moon set?
  • The correct answer is not explicitly provided in the visible text.

Transit Time Question

• What time does the full moon transit?
  • Options given: Midnight, Sunrise, Noon, Sunset.
  • The correct answer is not explicitly provided in the visible text.