In geophysical terms, the Moon is a planetary-mass object or satellite planet. Its mass is 1.2% that of the Earth, and its diameter is 3,474 km (2,159 mi), roughly one-quarter of Earth's (about as wide as the contiguous United States). The Moon makes Earth more livable, sets the rhythm of ocean tides, and keeps a record of our solar system's history.

Context Explanation

Explore NASA lunar science here. Use our Moon Phase Calendar to find dates and times of the full Moon, new Moon, and every phase in between. Beyond the phases of the Moon, you will also see daily Moon illumination percentages and the Moon's age. Track the moon phase today with our interactive moon phase calculator.

Insight Material

Get details on the current moon phase and the next full moon date. Moon Phase for today and tonight with current lunar phase, illumination percentage and Moons age. Find out what the Moon Phase is on any other day of the year. Learn about Moon phases and see our Moon Phase Calendar here. Enter your location to find your local moonrise and moonset ...

Final Conclusion

What is the moon made of, and how did it form? Learn about the moon's violent origins, how its phases shaped the earliest calendars, and how humans first explored Earth's only natural satellite half a century ago. How big is the Moon? The Moon is Earth’s only permanent natural satellite, and it’s the fifth-largest satellite in our solar system. The Moon’s diameter is approximately 2,160 miles (3,475...