地球围绕太阳移动速度时附近的远日点(它的轨道离太阳最近的点)。它远时速度慢(近日点),就像[开普勒][1]实现相当长一段时间前,小心他(第三行星运动定律)[2]。有很多方法去写一个公式来计算地球围绕太阳的速度。但对于你的问题我认为[这个][3]足够简单和通用:$ $ v = \√6 {G \ M_S \离开(\压裂{2}{r} - \压裂{1}{}\右)}$ $ * v *美元是地球的速度,* G *美元(引力常数)[5],M_S美元* *是太阳质量的(这个方程假设地球的质量相比可以忽略不计(质量)[6],这是一个很好的近似),* *美元美元(地球的轴)[7]的轨道(定义如何椭圆或圆形轨道),和* r *美元从地球到太阳的距离。最近和最远的距离分别是(大约1.471亿公里(大约1月3日),大约1.521亿公里(约7月4日)][8]。将这些数字插入方程得到* *最大速度为30.3公里/秒,最小为29.3公里/秒* *。对于任何给定的一天,太阳距离的计算很复杂,但是网站[这个][9],提供一个真正的时间价值可以用在上面的公式(该网站还提供了速度马上!]。这些值基本上是相同的从一年到另一个。然而,他们慢慢的改变的(偏心)[10]地球轨道所描述的逐渐变化为[米兰科维奇旋回][11]。现在,地球的绕自己的轴旋转的速度值是几乎相同的每一天; variations are of day length are on the order of [a fraction of a millisecond][12]. Part of that variation is periodic and more or less predictable and another part is from other less predictable factors. But for all practical proposes the length of the day is constant through the year. The following figure shows those tiny variations in day length since the early 1960's: [![daily deviation of length of day][13]][13] (image from Wikipedia commons, originally [here][14]) But as a consequence of these tiny variations, almost every year one or two ([leap seconds][15]) are added to our clocks to keep them aligned with the rotation of the Earth. In the long run (millennia), Earth days are getting longer. Some of the factors involved were discussed in [this question][16]. Finally to address whether changes in orbital speed affect rotational speed: I don't think so. For what I understand none of those small changes in the length of the day is a direct consequence of changes in the orbital speed. [1]: https://en.wikipedia.org/wiki/Johannes_Kepler [2]: https://en.wikipedia.org/wiki/Kepler%27s_laws_of_planetary_motion [3]: https://en.wikipedia.org/wiki/Orbital_speed [4]: https://i.stack.imgur.com/zd3Sz.png [5]: https://en.wikipedia.org/wiki/Gravitational_constant [6]: https://en.wikipedia.org/wiki/Sun [7]: https://en.wikipedia.org/wiki/Earth [8]: https://en.wikipedia.org/wiki/Perihelion_and_aphelion [9]: https://theskylive.com/sun-tracker [10]: https://en.wikipedia.org/wiki/Orbital_eccentricity [11]: https://en.wikipedia.org/wiki/Milankovitch_cycles [12]: https://en.wikipedia.org/wiki/Day_length_fluctuations [13]: https://i.stack.imgur.com/cy8xi.png [14]: https://en.wikipedia.org/wiki/File:Deviation_of_day_length_from_SI_day.svg [15]: https://en.wikipedia.org/wiki/Leap_second [16]: //www.hoelymoley.com/questions/13432/what-is-the-fastest-the-earth-has-ever-spun/13433#13433