sidereal time

简明释义

恒星时间

英英释义

例句

1.In astronomy, a day measured in sidereal time is approximately 23 hours and 56 minutes long.

在天文学中，以恒星时间测量的一天大约为23小时56分钟。

2.When planning an observation session, it's essential to convert local time to sidereal time for optimal viewing conditions.

在计划观测时，将当地时间转换为恒星时间以获得最佳观测条件是至关重要的。

3.Astronomers often use sidereal time to accurately track the positions of stars and planets throughout the night.

天文学家经常使用恒星时间来准确追踪星星和行星在夜空中的位置。

4.The difference between solar time and sidereal time is about 4 minutes each day.

太阳时间与恒星时间之间的差异大约是每天4分钟。

5.Using sidereal time, sailors can navigate more accurately by aligning their instruments with the stars.

通过使用恒星时间，水手可以通过将仪器与星星对齐来更准确地导航。

作文

Understanding the concept of sidereal time is essential for both astronomers and enthusiasts of celestial navigation. Unlike solar time, which is based on the position of the Sun in the sky, sidereal time is determined by the Earth's rotation relative to distant stars. This difference is crucial because it affects how we measure time and position in the universe.To grasp the importance of sidereal time, one must first understand the Earth's rotation. The Earth completes one full rotation on its axis approximately every 24 hours, which defines our day. However, this rotation does not occur in isolation; it also involves the orbiting of the Earth around the Sun. As a result, a solar day—the time it takes for the Sun to return to the same position in the sky—lasts about 24 hours, while a sidereal day, which is measured by the position of distant stars, is approximately 23 hours, 56 minutes, and 4 seconds.The difference between these two measurements arises because the Earth is moving along its orbit as it rotates. Each day, as the Earth spins, it also travels a bit further along its orbital path. Consequently, when we observe a star at a particular moment, it takes a little less than a full day for that same star to appear in the same position again. This phenomenon is the essence of sidereal time.For astronomers, sidereal time is a critical tool for locating celestial objects. When using telescopes, astronomers must account for this time difference to accurately track stars and planets. Observatories often use sidereal time to schedule observations and align their instruments. By understanding sidereal time, astronomers can ensure they are looking at the right part of the sky at the right moment.In practical terms, sidereal time is measured in hours, minutes, and seconds, just like solar time. However, instead of starting at midnight, sidereal time begins at a reference point known as the vernal equinox. This point marks the position of the Sun at the beginning of spring in the Northern Hemisphere and serves as a fixed point against which the positions of stars are measured.For those interested in navigation, understanding sidereal time can also be beneficial. Sailors and navigators have used celestial navigation for centuries, relying on the positions of stars to determine their location at sea. Knowing sidereal time allows them to make accurate calculations regarding their position relative to the stars, ensuring safe passage across vast oceans.In conclusion, sidereal time is a fundamental concept in astronomy and navigation. It provides a framework for understanding the movements of celestial bodies and is essential for accurate observations and calculations. By recognizing the differences between sidereal time and solar time, we gain a deeper appreciation for the complexities of our universe and the intricate dance of celestial mechanics that governs it. Whether you are an aspiring astronomer or simply someone curious about the cosmos, familiarizing yourself with sidereal time will enhance your understanding of the night sky and the wonders it holds.

理解恒星时间的概念对于天文学家和天体导航爱好者来说都是至关重要的。与基于太阳在天空中位置的太阳时间不同，恒星时间是由地球相对于遥远星星的自转决定的。这种差异至关重要，因为它影响我们如何测量时间和宇宙中的位置。要掌握恒星时间的重要性，首先必须理解地球的自转。地球大约每24小时完成一次完整的自转，这定义了我们的日子。然而，这种自转并不是孤立发生的；它还涉及地球围绕太阳的轨道运动。因此，太阳日——太阳返回天空中同一位置所需的时间——大约持续24小时，而恒星日（根据遥远星星的位置来测量）大约为23小时、56分钟和4秒。这两种测量之间的差异源于地球的运动。每天，当地球旋转时，它也沿着轨道向前移动。因此，当我们在特定时刻观察一颗星星时，这颗星星再次出现在同一位置所需的时间略少于整整一天。这一现象就是恒星时间的本质。对于天文学家来说，恒星时间是定位天体的重要工具。在使用望远镜时，天文学家必须考虑这种时间差，以准确跟踪星星和行星。天文台通常使用恒星时间来安排观测和调整他们的仪器。通过理解恒星时间，天文学家可以确保在正确的时刻观察天空的正确部分。在实际操作中，恒星时间以小时、分钟和秒来测量，就像太阳时间一样。然而，恒星时间不是从午夜开始，而是从一个称为春分点的参考点开始。这个点标志着太阳在北半球春季开始时的位置，并作为测量星星位置的固定点。对于那些对导航感兴趣的人来说，理解恒星时间也很有帮助。水手和导航员几个世纪以来一直使用天体导航，依靠星星的位置来确定他们在海上的位置。了解恒星时间使他们能够准确计算自己相对于星星的位置，从而确保在辽阔的海洋中安全航行。总之，恒星时间是天文学和导航中的基本概念。它提供了理解天体运动的框架，对于准确的观测和计算至关重要。通过认识到恒星时间和太阳时间之间的差异，我们对宇宙的复杂性以及支配其运行的天体力学的精妙舞蹈有了更深的理解。无论你是一个有抱负的天文学家还是仅仅对宇宙充满好奇的人，熟悉恒星时间将增强你对夜空及其所蕴藏奇迹的理解。