Why the changing shape of the moon?.

World Scientific reports [tech.] News: The ancient Greeks certainly think that the moon is all the objects in the sky from the Earth's nearest celestial body. .Therefore deserved it as is the second after the second Earth objects are concerned. .<P> Is the only moon in the sky, eternal, and can be seen every night it changes the shape of objects. .The sun always shine in the sky, brilliant light, the other planets and stars have always flashing in the night sky. .Some comets also have their own unique shape change, but we can not always be able to see them in the night sky. .</ P> <P> the shape of the moon to go through a series of specific, step by step, repetitive process of change. .In some special night, the moon to the sun sets behind the mountains just to the west crescent shape in the sky. .After one last night, the moon gradually remove the east, and it was gradually thin crescent-shaped "fat," up, about a week, it gradually became a semi-circular shaped, and continue to a more "fat" .the direction of change, until then a week later, it finally formed a "full moon." .Later still, it started getting thinner, smaller, a week later, it returned to semi-circular state (however, this is the other half of the moon became brighter.) .Next, another a week later, it finally dawn before the time the sky in the east, but also into a crescent shape. .It will disappear the next few nights, and then appeared again, repeat the above process of change. .</ P> <P> people will naturally think the moon is a life-like body, it gradually from birth to grow until it reaches the peak of life, and then will gradually aging, and ultimately to death. .In the month through this series of stages. .Even today, we will still appear in the western sky as a thin crescent "moon", and will appear in the east end of month, the thin crescent in the sky known as the "moon" in this process .the middle is called "full moon." .As I explained earlier, we will change the complete cycle of the moon to establish a "month." .The first calendar was produced on this basis. .But why do these changes occur? .Month will not really have a new moon "born" mean? .</ P> <P> ancient Greek philosopher Taiwan Aires do not think so, and in the Babylonian astronomers before him, probably did not think so. .Skeptical of the reasons come from the moon in this month relative to the position change of the sun. .In the beginning, naturally imagine that all things on earth followed by the natural law is different from the objects in the sky who followed the laws of nature. .On Earth, all objects fall towards; in the sky, all objects are in circular motion. .On Earth, everything is constantly changing until failure; in the sky, everything seems to be eternal, unchanging. .Earth material is non-luminous; in the sky, all objects are constantly flashing. .If the material composition of the moon is like the sun, planet or star that made a stop light, then the moon in the sky will be a constant ball of light. .Since the moon is not a ball of light never changes, it will have growth in the month, and the aging process, but is not permanently illuminated. .If the moon is dark, like Earth, can only rely on reflected sunlight to make their own light, then reflected on it in different parts of the sun, appeared to depend on the position of the sun in the sky. .</ P> <P> example, if the moon is exactly in the middle of the earth and the sun, then the sun will be shining on the moon back to our side. .Therefore, we will not see anything from the moon. .When the moon is at 12 times the speed of the sun from west to east, the next night, it will appear a little east of the sun's position, so we can actually see the moon lit the western edge of the curved thin .thin crescent moon, which is based on "New Moon" in the form of. .As the moon continues to turn east, we can see some will be increasing, so the "new moon" to gradually become "fat" together. .When the moon in the sky and turned 1 / 4 distance, when compared with the sun, west of it is illuminated, so we see a bright half months. .Next, it continues to change, until the moon and the sun in the sky relative to the side, then, both sides of the sun through the earth, the moon in front of us lit up the entire side, so we see .is a "full moon." .</ P> <P> later, then gradually catch up with the sun, the moon, we see some light was beginning to be narrowed. .A week later, only the eastern half points also remain bright, and then after they gradually become a Crescent Moon. .At this time the sun is over the moon, the next and repeat the process of change. .Any person, if you think about the change process, you will end up with a conclusion: the moon and Earth, he is not illuminated, can only rely on reflected sunlight to make their own light. .</ P> </ p>.