First Quarter

Definition

The first quarter is the phase of the Moon when the Moon's illuminated half is facing the right side from the perspective of an observer on Earth, appearing as a half-moon. This phase occurs approximately one week after a new moon, when the Moon has completed a quarter of its orbit around the Earth.

5 Must Know Facts For Your Next Test

1. During the first quarter phase, the Moon's illuminated side is facing the right from the perspective of an observer on Earth.
2. The first quarter phase occurs approximately one week after a new moon, when the Moon has completed a quarter of its orbit around the Earth.
3. The first quarter phase is part of the waxing moon period, where the illuminated portion of the Moon is increasing.
4. The position of the Moon during the first quarter phase contributes to the formation of tidal bulges on Earth.
5. The first quarter phase is an important reference point for understanding the Moon's overall phases and its relationship to the Earth's tides.

Review Questions

• Explain how the first quarter phase of the Moon is related to its overall phases and motions.
  • The first quarter phase occurs approximately one week after a new moon, when the Moon has completed a quarter of its orbit around the Earth. This phase is part of the waxing moon period, where the illuminated portion of the Moon is increasing. The first quarter phase is an important reference point for understanding the Moon's overall phases, as it marks the transition from the new moon to the full moon, and the beginning of the Moon's waxing period.
• Describe the role of the first quarter phase in the formation of ocean tides.
  • The position of the Moon during the first quarter phase contributes to the formation of tidal bulges on Earth. The Moon's gravitational pull creates these areas of increased water level on opposite sides of the Earth. The first quarter phase is an important factor in understanding the relationship between the Moon's phases and the Earth's ocean tides, as the Moon's position relative to the Earth during this phase influences the strength and timing of the tides.
• Analyze how the first quarter phase of the Moon relates to both its phases and motions, as well as its impact on ocean tides.
  • The first quarter phase of the Moon is a critical point in the Moon's overall phases and motions, occurring approximately one week after a new moon when the Moon has completed a quarter of its orbit around the Earth. This phase is part of the waxing moon period, where the illuminated portion of the Moon is increasing. The position of the Moon during the first quarter phase also contributes to the formation of tidal bulges on Earth, as the Moon's gravitational pull creates areas of increased water level on opposite sides of the planet. Understanding the first quarter phase and its relationship to the Moon's phases, motions, and impact on ocean tides is essential for comprehending the complex interactions between the Earth and Moon.

Related terms

Lunar Phases: The different appearances of the Moon as it orbits the Earth, including new moon, first quarter, full moon, and last quarter.

Waxing Moon: The period of the Moon's cycle when the illuminated portion is increasing, from new moon to full moon.

Tidal Bulges: The two areas of increased water level on opposite sides of the Earth caused by the Moon's gravitational pull.