As the sun and moon gravity on the Earth's equatorial bulge part of the role and the axis tilt of the ecliptic, causing the vernal equinox point westward to return in the short than the sidereal year phenomenon. Around 150 BC by the Greek astronomer Hipparchus first discovered. China's earliest astronomers to set precise age difference is Jin Yuxi (281-356).
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suì chà
Around an axis through the center of the earth surface but perpendicular to the axis of the ecliptic slow conical movement cycle 26,000 years from the sun, moon and other planets on the Earth's equatorial bulge caused by the attractiveness of property; result equinox gradually move westwards
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No. 3
岁差
岁差
岁差
岁差
As the sun and the moon's gravity to Earth's equator, the small effect, so that the axis around the axis of the ecliptic for conical movement, moving slowly westward, about 26 000 years around a week, while making vernal equinox each year, the rate of 50.2 arcsec westward movement of line. This phenomenon is called precession. More precise age of the earliest to set the margin is the Jin Yuxi, come to "five years of retirement once" conclusion, make our calendar years earlier distinction between the star and the solar year. The calendar is the first calculation of precession Zu Chong Zhi's "Daming calendar." "Art of the Sui Xuan Chuan Zhang helmet": "SONG Zu Chong Zhi at the end of week-old, the creation of difference, the winter solstice gradually shift, do not follow the old track. Every 40 years, but once poor." Shen Song include "Meng Xi Bi Tan as the number one ":" Chinese world has not known the ecliptic precession. to the Northern Qi Zhang Zixin side waiting to know precession. "" Yuan History Li Chih-yi ":" to Jin Yuxi, Song Hecheng days, Zu Chong Zhi, that age when there is poor, due to legislative precession of the law. "Taiping Rengan" Aviva Allah ":" Heavens line to health, Verily there is often, the non-ancient and modern, different. The precession Shrinkage Chi Ji Zhu line, now there are no old and even their number Micro, Sekihisa start with. "
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No. 4
equinoxes, precession of The precession of Earth's rotation axis caused by the displacement of the equinox phenomenon. In Japan, under the effect of gravity on the Earth's rotation axis is not fixed point of space, showing through the center of the earth for the round one with the axis perpendicular to the ecliptic plane is slow and continuous motion, clockwise to about 25 800 years (from the northern hemisphere to see) revolution, describing a conical surface. This conical surface angle equal to the obliquity of the ecliptic 23. ° 5. So YORK around the yellow pole on the celestial sphere with a radius of paint 23. ° 5 of the small round, but also the vernal equinox and the sun along the Yellow River Road to the annual apparent motion in the opposite direction one revolution every 25,800 years, the westward movement of about 50 per year. "3. This caused by the sun and the moon the long-term precession of the axis (or precession) is called lunisolar precession. In addition, under the gravitational pull of planets, the Earth's orbit plane constantly change position, which not only changes in obliquity of the ecliptic , also the vernal equinox along the equator to produce a small displacement, the direction of the sun and the moon precession contrast, this effect is called planetary precession. precession of the equinox along the planetary equator, the eastward shift of about 0 a year. "13 Lunisolar precession and planetary precession of the combination of the coordinates of celestial bodies such as the right ascension and declination and other changes, within one year anniversary of the change is called precession. Moreover, according to general relativity, the spin axis will rotate objects in space produce relativistic precession, called geodetic precession. The geodetic precession of the Earth 1. "98 / century, to the counterclockwise direction.
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What is the precession
In layman's terms, is well known that the Earth is similar to top, around the axis of rotation. Gyro rotation does not exactly parallel to the ground turning. Suffered on both sides of this gyro gravity imbalance or even stop shaking. Earth, too, which resulted in the "precession." Precession precession of Earth's rotation axis is caused by the displacement of the equinox phenomenon. In Japan, under the effect of gravity on the Earth's rotation axis is not fixed point of space, showing through the center of the earth for the round one with the axis perpendicular to the ecliptic plane is slow and continuous motion, clockwise to about 25 800 years (from the northern hemisphere to see) revolution, describing a conical surface. This conical surface angle equal to the obliquity of the ecliptic (23.5 ° 26'21 "). So YORK around the yellow pole on the celestial sphere depicts a small circle of radius 23.5 °, but also the vernal equinox and the sun along the Yellow River Road to the contrary the annual apparent motion the direction of the revolution every 25,800 years, the westward movement of about 50.3 per year. " This caused by the sun and the moon the long-term precession of the axis (or precession) is called lunisolar precession. In addition, the gravitational pull of planets, the Earth's orbit plane constantly change position, which not only changes in obliquity of the ecliptic, the vernal equinox along the equator also produce a small displacement, the direction of the sun and the moon precession contrast, this effect is called planetary precession. Planetary precession make the vernal equinox eastward along the equator of about 0.13 per year. "Lunisolar precession and planetary precession of the combination of the coordinates of celestial bodies such as the right ascension and declination and other changes, within one year anniversary of the change is called precession. In addition, according to the generalized theory of relativity, rotating the spin axis of the object in space produce relativistic precession, called the geodetic precession of Earth's geodetic precession of 1.98 "/ century, to the counterclockwise direction. Earth's equator with their orbits, "Zodiac" does not coincide, the intersection where they face is the vernal equinox and autumnal equinox. The sun from the vernal equinox back to the time the vernal equinox is called the tropical year, the time required for the Earth's revolution a year is called the sidereal year. Shorter than the sidereal year tropical year by about 20 minutes, when the closing movement of the earth gravitational pull of other celestial bodies to the earth's axis due to cyclical changes occur
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What impact precession
岁差影响了什么
Precession and nutation caused by the relative position of the vernal equinox YORK and stars change. Because of precession, the North Star changes over time. Sky star Polaris is ancient, Tai, Royal Star, Tianshu. After the hook Chen Yicheng Song is now Polaris. After a thousand years, Vega will become the North Star. Because of precession, the ancient Greek period, twelve constellations has been increased to thirteen (increase of Ophiuchus). Solar calendar of the next year and the precession is also the leap home.
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Who discovered the precession
1 East: Yuxi Fourth century AD, Chinese astronomers Yuxi Jin Dynasty, in the analysis of ancient star maps and sky, we found the location of stars slightly off_set_, and then discovered precession, and _set_ back 50 years, every winter solstice point of 1 °. "Sung legal Calendar," it reads: "Yuxi Yun: 'Yao short winter solstice, when the Pleiades star, this two thousand seven hundred years, is the eastern wall, you know that every age has become worse of the actions,'" the term that the precession resulting. 2 West: Hipparchus The second century BC, the ancient Greek astronomer Hipparchus in the preparation of a star contains 1,022 stars of the table, he measured the stars, and 150 years ago, Ali Christie Cornelius and 提莫恰里斯 determination horoscope for comparison and found the yellow star by the more significant changes, and changes in latitude was not significant. In 150 years, all the yellow stars are increased by about 1 ° 5. Hipparchus that this is the vernal equinox along the Yellow River Road back the result, and calculate the vernal equinox every 100 years the westward movement of 1 °. This is the first discovered the phenomenon of precession.
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Astronomy 百科
岁差 天文百科
Earth is like a spinning top, and the gyro in the rotation, its axis is not perpendicular to the ground completely immobile, but also in shaking slightly, a phenomenon in physics known as "precession." Earth, too, its spin axis direction in the sky is changing, not always point to a fixed point, which is called the precession in astronomy.
