semi-major axis

简明释义

长半轴

英英释义

例句

1.The semi-major axis of a comet's orbit can change significantly over time due to gravitational interactions.

彗星轨道的半长轴由于引力相互作用而可能随时间显著变化。

2.In astronomy, the semi-major axis is crucial for calculating the orbital period of a planet.

在天文学中，半长轴对计算行星的轨道周期至关重要。

3.The length of the semi-major axis of an ellipse determines its size and shape.

椭圆的半长轴长度决定了它的大小和形状。

4.The semi-major axis of Earth's orbit around the Sun is about 149.6 million kilometers.

地球围绕太阳的轨道的半长轴约为1.496亿公里。

5.To find the area of an ellipse, you can use the formula that includes the semi-major axis.

要找到椭圆的面积，可以使用包含半长轴的公式。

作文

In the realm of astronomy, understanding the structure and dynamics of celestial bodies is essential. One of the fundamental concepts in this field is the concept of the orbit, particularly the elliptical orbit. An ellipse, which is a closed curve, is defined by its two focal points. The distance from the center of the ellipse to one of its foci is known as the focal length, while the longest diameter of the ellipse is referred to as the major axis. However, when discussing orbits, one key parameter stands out: the semi-major axis. The semi-major axis (半长轴) is defined as half of the length of the major axis and represents the average distance of an orbiting body from the central body it revolves around. This measurement is critical for determining various orbital characteristics, such as the period of revolution and the shape of the orbit. For example, consider the orbit of Earth around the Sun. The average distance from the Earth to the Sun is approximately 93 million miles, which corresponds to about 1 astronomical unit (AU). This distance is essentially the semi-major axis (半长轴) of Earth's elliptical orbit. Understanding this distance allows astronomers to calculate how long it takes for the Earth to complete one full orbit, which is about 365.25 days. This is a crucial factor in our understanding of seasons and the passage of time. Moreover, the semi-major axis (半长轴) is not only important for Earth but also for other celestial bodies in the solar system. For instance, the planet Jupiter has a much larger semi-major axis (半长轴) compared to Earth, which means it is farther away from the Sun and has a longer orbital period. Jupiter takes approximately 11.86 Earth years to complete one orbit around the Sun, illustrating how the semi-major axis (半长轴) directly influences the orbital dynamics of a planet. In addition to its role in planetary orbits, the semi-major axis (半长轴) is also crucial in understanding the trajectories of comets and asteroids. These objects often have highly eccentric orbits, meaning their distance from the Sun varies significantly throughout their orbital path. By analyzing the semi-major axis (半长轴) of these orbits, scientists can predict when a comet will return to the inner solar system or assess the potential impact risks of asteroids. Furthermore, the semi-major axis (半长轴) is a key parameter in Kepler's laws of planetary motion. According to Kepler's third law, the square of the orbital period of a planet is directly proportional to the cube of the semi-major axis (半长轴) of its orbit. This relationship provides a powerful tool for astronomers to compare the orbits of different planets and to understand the gravitational forces at play in the solar system. In conclusion, the semi-major axis (半长轴) is a fundamental concept in astronomy that serves as a critical measure of the size and shape of an orbit. It plays a vital role in determining the orbital characteristics of celestial bodies, influencing everything from the length of a year on Earth to the trajectories of distant comets. By grasping the significance of the semi-major axis (半长轴), we can deepen our understanding of the intricate dance of the cosmos and the forces that govern it.

在天文学领域，理解天体的结构和动态是至关重要的。这个领域中的一个基本概念是轨道，特别是椭圆轨道。椭圆是一个封闭曲线，其由两个焦点定义。椭圆中心到其中一个焦点的距离被称为焦距，而椭圆的最长直径则称为主轴。然而，在讨论轨道时，有一个关键参数显得尤为突出：半长轴。半长轴（semi-major axis）定义为主轴长度的一半，表示围绕中心天体旋转的天体的平均距离。这个测量对于确定各种轨道特性至关重要，例如革命周期和轨道形状。例如，考虑地球围绕太阳的轨道。地球到太阳的平均距离大约为9300万英里，这大约对应于1个天文单位（AU）。这个距离本质上就是地球椭圆轨道的半长轴。理解这个距离可以让天文学家计算地球完成一整圈所需的时间，即大约365.25天。这是我们理解季节和时间流逝的关键因素。此外，半长轴（semi-major axis）不仅对地球重要，对太阳系中的其他天体也是如此。例如，行星木星的半长轴（semi-major axis）比地球大得多，这意味着它离太阳更远，并且有更长的轨道周期。木星大约需要11.86个地球年才能完成一次围绕太阳的轨道，这说明了半长轴（semi-major axis）如何直接影响行星的轨道动力学。除了在行星轨道中的作用外，半长轴（semi-major axis）在理解彗星和小行星的轨迹方面也至关重要。这些天体通常具有高度偏心的轨道，这意味着它们与太阳的距离在轨道路径中变化显著。通过分析这些轨道的半长轴（semi-major axis），科学家可以预测彗星何时会返回内太阳系，或评估小行星的潜在撞击风险。此外，半长轴（semi-major axis）是开普勒行星运动定律中的一个关键参数。根据开普勒的第三定律，行星的轨道周期的平方与其轨道的半长轴（semi-major axis）立方成正比。这一关系为天文学家提供了一个强大的工具，以比较不同行星的轨道，并理解太阳系中起作用的引力。总之，半长轴（semi-major axis）是天文学中的一个基本概念，作为轨道大小和形状的重要测量标准。它在确定天体的轨道特性方面发挥着至关重要的作用，影响从地球上的一年长度到遥远彗星的轨迹的方方面面。通过掌握半长轴（semi-major axis）的意义，我们可以加深对宇宙复杂舞蹈及其支配力量的理解。