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 United States from coast to coast).
2 天之前 · Moon, Earth’s sole natural satellite and nearest celestial body. Known since prehistoric times, it is the brightest object in the sky after the Sun. Its name in English, like that of Earth, is of Germanic and Old English derivation.
2024年12月5日 · Earth has just one moon – a rocky, cratered place, roughly a quarter the size of Earth and an average of 238,855 miles away. The Moon can be seen with the naked eye most nights as it traces its 27-day orbit around our planet.
As the Moon orbits Earth, different parts are in sunlight or darkness at different times. The changing illumination is why, from our perspective, the Moon goes through phases. During a "full moon," the hemisphere of the Moon we can see from Earth is fully illuminated by the Sun.
The brightest and largest object in our night sky, the Moon makes Earth a more livable planet by moderating our home planet's wobble on its axis, leading to a relatively stable climate. It also causes tides, creating a rhythm that has guided humans for thousands of years.
2023年11月22日 · The Moon completes an orbit of the Earth every 27.3 days (approximately 655 hours). The Moon also rotates on its axis. Because of tidal forces, it completes one revolution every 655 hours.