Moon is shown as the beautiful circular
light from the Earth. Therefore, in the past time, human realized that the
earth is a holy thing. So many people have the great mythology about moon. Some
of them call the moon as God, and any other mythology. This is happen because
the moon just shown as far object that cannot be reached by human in that time.
The Moon is Earth's only natural
satellite and the fifth largest satellite in the Solar System. It is the
largest natural satellite in the Solar System relative to the size of its
planet, a quarter the diameter of Earth and 1/81 its mass, and is the second
densest satellite after Io. It is in synchronous rotation with Earth, always
showing the same face; the near side is marked with dark volcanic Maria among
the bright ancient crustal highlands and prominent impact craters. It is the
brightest object in the sky after the Sun, although its surface is actually
very dark, with a similar reflectance to coal. Its prominence in the sky and
its regular cycle of phases has since ancient times made the Moon an important
cultural influence on language, the calendar, art and mythology. The Moon's
gravitational influence produces the ocean tides and the minute lengthening of
the day. The Moon's current orbital distance, about thirty times the diameter
of the Earth, causes it to appear almost the same size in the sky as the Sun,
allowing it to cover the Sun nearly precisely in total solar eclipses.
The Moon is the only celestial body on
which humans have landed. While the Soviet Union's Luna program was the first
to reach the Moon with unmanned spacecraft in 1959, the United States' NASA
Apollo program achieved the only manned missions to date, beginning with the
first manned lunar orbiting mission by Apollo 8 in 1968, and six manned lunar
landings between 1969 and 1972—the first being Apollo 11 in 1969. These
missions returned over 380 kg of lunar rocks, which have been used to develop a
detailed geological understanding of the Moon's origins (it is thought to have formed
some 4.5 billion years ago in a giant impact event involving Earth), the
formation of its internal structure, and its subsequent history.
After the Apollo 17 mission in 1972, the
Moon has been visited only by unmanned spacecraft, notably by Soviet Lunokhod
rovers. Since 2004, Japan, China, India, the United States, and the European
Space Agency have each sent lunar orbiters. These spacecraft have contributed
to confirming the discovery of lunar water ice in permanently shadowed craters
at the poles and bound into the lunar regolith. Future manned missions to the
Moon are planned but not yet underway; the Moon remains, under the Outer Space
Treaty, free to all nations to explore for peaceful purposes.
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