The Moon is the only natural satellite of Earth, and is the largest natural satellite in the Solar System 5. Moon does not have its own light source and the light comes from the moon is actually reflected sunlight.
The average distance from the Earth-Moon center to center is 384 403 km, about 30 times the diameter of Earth. The diameter of the Moon is 3474 km, [1] a little less than a quarter the diameter of Earth. This means that the volume of the Moon is only about 2 percent of the volume of the Earth and the pull of gravity at its surface about 17 percent than the gravitational pull of the Earth. Moon revolves around the Earth once every 27.3 days (the orbital period), and the periodic variations in the Earth-Moon-Sun responsible for the phases of the Moon are repeated every 29.5 days (the period sinodic).
The
density of the Moon (3.4 g / cm ³) is lighter than the density of the
Earth (5.5 g / cm ³), while the mass of the Moon is only 0.012 Earth
masses.
Months
pulled by Earth's gravity does not fall to the Earth due to the
centrifugal force arising from the orbit of the Moon around the Earth. The
magnitude of the centrifugal force, the Moon is slightly larger than
the gravitational attractive forces between the Earth and the Moon. This causes the moon farther away from Earth at a speed of about 3.8 cm / year.
Moon is in sync with the Earth's orbit, this led to only one side of the Moon's surface that can be observed from Earth. Synchronous orbit with rotation causes kala kala revolution.
On the moon there is no air or water. Terhasil many craters on the lunar surface which is caused by a comet or asteroid hit. The
absence of air and water on the moon cause the absence of erosion
causing many craters on the moon millions of years and is still intact. Among the biggest is the Clavius crater with a diameter of 230 kilometers and a depth of 3.6 kilometers. The lack of air also causes no sound can be heard on the moon.
The Moon is the only celestial objects that had visited and landed humans. The
first artificial object that pass near the Moon was the Soviet Union
owned spacecraft, Luna 1, the first artificial object that hit the
Moon's surface was Luna 2, and the first photo of the moon's far side
that was never visible from the Earth, taken by Luna 3, all these
missions conducted in 1959. The
first spacecraft to successfully perform the landing was Luna 9, and
the successful orbit the Moon was Luna 10, both made in 1966. [1] Apollo
Program of the United States is the only manned missions to date, which
made six manned landings between 1969 and 1972.
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