Phases of the Moon to Know for Intro to Astronomy

The phases of the Moon are a fascinating aspect of astronomy, showcasing its changing appearance as it orbits Earth. Understanding these phases helps us appreciate the lunar cycle's impact on culture, nature, and our night sky.

1. New Moon

   • The Moon is positioned between the Earth and the Sun, making it invisible from Earth.
   • Marks the beginning of the lunar cycle, occurring approximately every 29.5 days.
   • Represents a time of new beginnings and is often associated with renewal in various cultures.

2. Waxing Crescent

   • A small sliver of the Moon becomes visible as it moves away from the New Moon phase.
   • The illuminated portion increases, or "waxes," as the Moon orbits the Earth.
   • This phase lasts until the Moon reaches the First Quarter, typically about a week after the New Moon.

3. First Quarter

   • The Moon is half-illuminated and appears as a semi-circle in the sky.
   • Occurs roughly one week after the New Moon, marking the halfway point to the Full Moon.
   • The Moon is positioned at a 90-degree angle relative to the Earth and Sun.

4. Waxing Gibbous

   • More than half of the Moon is illuminated, but it is not yet full.
   • This phase occurs between the First Quarter and Full Moon, lasting about a week.
   • The Moon continues to grow in brightness and size as it approaches the Full Moon.

5. Full Moon

   • The entire face of the Moon is illuminated, making it fully visible from Earth.
   • Occurs approximately two weeks after the New Moon, marking the peak of the lunar cycle.
   • Often associated with various cultural and natural phenomena, such as tides and lunar festivals.

6. Waning Gibbous

   • The Moon begins to decrease in illumination after the Full Moon, but more than half remains visible.
   • This phase lasts until the Moon reaches the Last Quarter, typically about a week.
   • The illuminated portion "wanes," or decreases, as the Moon continues its orbit.

7. Last Quarter

   • The Moon is again half-illuminated, but this time the opposite side is lit compared to the First Quarter.
   • Occurs roughly three weeks after the New Moon, marking the transition to the Waning Crescent.
   • The Moon is positioned at a 90-degree angle relative to the Earth and Sun, similar to the First Quarter.

8. Waning Crescent

   • A small crescent of the Moon remains visible as it approaches the New Moon phase.
   • The illuminated portion continues to decrease until it becomes invisible again.
   • This phase signifies the end of the lunar cycle and lasts about a week before the New Moon.