Which Moon phase shows illumination greater than half and decreasing toward the New Moon?

Which Moon phase shows illumination greater than half and decreasing toward the New Moon?

• A. New Moon
• B. Waning Gibbous Moon
• C. Full Moon
• D. Last Quarter

Answer: (B)

The Moon’s visible illumination is the fraction of its sunlit side we can see from Earth, and that amount changes as it orbits. After the Full Moon, the lit portion is still more than half but it’s shrinking as the Moon moves toward New Moon. That stage is Waning Gibbous: more than half lit, and the brightness is decreasing toward New Moon. The other phases don’t fit this description—New Moon has little or no illumination; Last Quarter is exactly half; Waning Crescent is less than half; Full Moon is fully illuminated and not described as decreasing toward New Moon.

The Moon’s visible illumination is the fraction of its sunlit side we can see from Earth, and that amount changes as it orbits. After the Full Moon, the lit portion is still more than half but it’s shrinking as the Moon moves toward New Moon. That stage is Waning Gibbous: more than half lit, and the brightness is decreasing toward New Moon. The other phases don’t fit this description—New Moon has little or no illumination; Last Quarter is exactly half; Waning Crescent is less than half; Full Moon is fully illuminated and not described as decreasing toward New Moon.