| 词汇 | perihelion |
| 释义 | perihelion noun[ C or U ] physics specializeduk /ˌper.ɪˈhiː.li.ən/ us /ˌper.ɪˈhiː.li.ən/pluralperiheliauk /ˌper.ɪˈhiː.li.ə/ us /ˌper.ɪˈhiː.li.ə/ the point in an object's orbit(= a curved path in space around a planet or star) around the sun at which the object is closest to the sun: 近日点 In January the Earth reaches perihelion.一月份地球到达近日点。 Opposite aphelion Physics: particular theories & concepts aphelion azimuth conservation cryogenics dark matter Doppler effect emergence emergent kinetics momentum perigee Planck's constant quantum refraction relativistic relativity spatio-temporal spring constant time dilation wormhole Examples of perihelionperihelion In the low and nominal cases maximum exposure occurs in the southern hemisphere at perihelion, intuitively consistent with a relatively optically thin atmosphere. Also, the increased daytime period is evident towards perihelion, escalating further the total daily dose. One, after a sensational first-sighting, seems to have retreated to outer space; its last perihelion was a disappointment. The general shape of the diurnal profiles between perihelion and aphelion are similar, but dose values vary markedly. Einstein found that his theory correctly ' predicted, ' actually retrodicted, the numerical value of the perihelion advance. Einstein's derivation of the perihelion advance, which was based on an approximation, had, however, one blemish: the uniqueness of the solution remained questionable. When the perihelion passage takes place in northern summer, the maximum temperature is lower in the southern hemisphere, so the soil humidity is higher in the south. The remaining three orbital elements - the longitude of the ascending node, the argument of perihelion, and the mean anomaly - were each randomly selected from the range 0-360x. The comet brightened steadily as it approached perihelion. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. During the 2005 perihelion passage the comet brightened to about apparent magnitude 16. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Unlike a long-period comet, the next perihelion passage of a numbered periodic comet can be predicted with a high degree of accuracy. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. At its closest, it is only 0.26 astronomical units away from the sun, having the 32nd closest perihelion of any minor planet. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Also, since perihelion and aphelion do not happen on exactly the same dates as the solstices, the maxima and minima are slightly asymmetrical. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. In 2004, residents of the southern hemisphere had the opportunity to watch the comet gradually brighten as it raced toward perihelion. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Increasing the eccentricity lengthens the time spent near aphelion and shortens the time near perihelion. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. These examples are from corpora and from sources on the web. Any opinions in the examples do not represent the opinion of the Cambridge Dictionary editors or of Cambridge University Press or its licensors. |
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