Why is the planet called "line" star?.

<P> Technology Channel (http://tech.) Message: Here I do not intend to and discussion of stars and planets were in the physical. .Would like to discuss with you is on the celestial sphere of stars and planetary motion characteristics. .</ P> <P align=center> </ P> <P> star of the "constant" stands for his position on the celestial sphere is constant, the article mentioned in the celestial sphere of stars in the sky in the direction of movement .not chaotic, but does not change the shape of the constellation. .Star from the east horizon to climb, to climb the highest point (transit), and then sank to the west. .Looks like the entire celestial sphere as rotating around the Earth. .(Note: In fact, the location of stars on the celestial sphere will change in fact, we call on the motion of stars in the celestial sphere as their own, but very, very slow moving star, insisted after several decades, coupled with accurate .The measure, to be able to detect it). .</ P> <P> planet "line" and not one word on their behalf never stop in the same constellation, which will be near the ecliptic on the celestial sphere around the battles, they are loitering around, because they, like the Earth .these will revolve around the sun. .</ P> <P align=center> </ P> <P> Here are some planets on the celestial sphere used to describe common terms to run: </ P> <P> "anterograde", "retrograde" and "stay ."</ P> <P> solar system planets revolve around the sun from west to east direction. .As a result of planetary orbital speed and its orbit different positions on the Earth Observing planets, the planets move in the direction of the Earth to the same direction (ie from west to east movement), then called "anterograde", opposite direction .called "retrograde", when converted into retrograde, anterograde or retrograde transfer into the smooth line, when the planet appears to be stationary is called "stay." .</ P> <P> Here are some of the planet and the Earth used to describe the transition in the public lane corresponding terms: </ P> <P> "integration" and "red" </ P> <P align=center> < ./ P> <P> Planet Earth at the transition of its public trail running, when the planets, the Earth and sun form a straight line called the "closing" or "red." .</ P> <P> to the inner planets (ie planets inside Earth's orbit, is the inner planets Mercury and Venus), the sun is between the planets and the Earth, called "SCO", the planets between the sun and the Earth .When called "inferior conjunction." .</ P> <P> to the outer planets (ie planets outside the Earth's orbit, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto are the outer planets), the sun is between the planets and the Earth called the "joint" .the earth and the sun in the middle of planets called "red", this time from the nearest planets and the Earth is the best time observations. .</ P> <P> "Big Sandy": </ P> <P> the inner planets (ie Mercury and Venus) orbit the Earth within the orbit. .It seems from the earth, they and the sun is always inseparable from the sun, sun go west of the east, then back east. .Because they are very close to the sun, so we only before sunrise or late afternoon to see them. .When the inner planets, Earth and the sun angle formed by three stars from the maximum called the "Big Sandy", can be observed the longest. .</ P> <P> the east of the planet to the sun "of Tokyo from" behind the planets will appear on the western horizon in line, and this was the best time for observing the planet. .</ P> <P> "West Big Sandy" that said the west side of the planet to the sun. .Planet from the east before sunrise on the horizon rise because of the need observation before sunrise, so the conditions of observation is less than the "East Big Sandy." .</ P> <P> there, Venus appeared before sunrise, we called the morning star, the sun will be called the evening star appears before. .</ P> <P> "transit" </ P> <P> "transit" is the Sky in the "food" a, the principle is similar with the solar eclipse is from the inner planets, the day passed, .We see a black spot in the plane slowly passing day, such as the transit of Mercury and the transit of Venus. .</ P> <P> Mercury's orbit and the ecliptic plane angle between the VII, May and November each year Mercury orbit the Earth through the intersection and down near the intersection, if the Mercury at inferior conjunction is just to .transit of Mercury occurs in the phenomenon. .Far away from Mercury and the Sun, Mercury, the sun's diameter is only about 1 / 285, so we used binoculars to projection observed transit of Mercury can only see a small black spot slowly swept from the surface of the sun .before. .</ P> <P> transit of Mercury </ P> <P> the transit of Venus since the phenomenon longer period of revolution and other factors it is relatively rare, occurring once separated by about 105 years, then every 8 years and again, and then to wait .121.5 years to see once and then for eight years and happened again. .The last transit of Venus in 1874 and 1882, the next will be June 8, 2004 and June 6, 2012 occurred. .</ P> <P align=center> </ P> </ p>.