Greenwich hour angle

简明释义

格林时角

英英释义

例句

1.The Greenwich hour angle is essential for calculating local sidereal time.

格林威治时角对于计算当地恒星时间至关重要。

2.Using the Greenwich hour angle, we can convert between different time zones.

利用格林威治时角，我们可以在不同的时区之间进行转换。

3.The astronomer calculated the Greenwich hour angle to determine the position of celestial bodies in the night sky.

天文学家计算了格林威治时角以确定夜空中天体的位置。

4.In astronomy, the Greenwich hour angle helps in tracking the movement of stars and planets.

在天文学中，格林威治时角有助于跟踪恒星和行星的运动。

5.To navigate accurately at sea, sailors must understand the concept of Greenwich hour angle.

为了在海上准确导航，水手必须理解格林威治时角的概念。

作文

The concept of time is fundamental to our daily lives, and understanding how time is measured is crucial for various fields, including navigation, astronomy, and even everyday activities. One important term related to time measurement is the Greenwich hour angle, which plays a significant role in celestial navigation. The Greenwich hour angle refers to the angle between the observer's meridian and the Greenwich meridian, measured in degrees. This angle helps determine the position of celestial objects in the sky relative to the Earth, particularly for navigators at sea who rely on accurate timekeeping to chart their course.Historically, the establishment of Greenwich Mean Time (GMT) in the 19th century provided a standard reference for time across the globe. The Greenwich hour angle is directly linked to GMT, as it allows for the calculation of local solar time based on the position of the sun. When the sun is at its highest point in the sky, it is noon at that location, and the Greenwich hour angle can be used to determine how far ahead or behind local time is compared to GMT.For example, if a navigator is situated at a longitude of 75 degrees west, they can calculate their Greenwich hour angle by determining how many degrees they are away from the Greenwich meridian. Since the Earth rotates 15 degrees per hour, each degree of longitude corresponds to four minutes of time. Thus, a navigator at 75 degrees west would have a Greenwich hour angle of 75 degrees, which translates to a time difference of three hours behind GMT.Understanding the Greenwich hour angle is essential not only for navigation but also for astronomical observations. Astronomers use this angle to track the movement of stars and planets across the night sky. By knowing the Greenwich hour angle, they can predict when specific celestial events will occur, such as eclipses or transits, and plan their observations accordingly.In modern times, with the advent of technology and GPS systems, the reliance on the Greenwich hour angle may seem diminished. However, it remains a foundational concept in the field of astronomy and navigation. The principles behind the Greenwich hour angle continue to be taught in schools and universities, ensuring that future generations understand the importance of time measurement and its relation to the Earth's rotation.In conclusion, the Greenwich hour angle is a vital concept that connects timekeeping with navigation and astronomy. It demonstrates how our understanding of time is intricately linked to the movement of celestial bodies. As we continue to explore the universe and navigate our planet, the Greenwich hour angle serves as a reminder of the precision and accuracy required in these endeavors. Whether we are sailing across the ocean or gazing at the stars, the Greenwich hour angle remains a key element in our quest for knowledge and exploration.

时间的概念对我们的日常生活至关重要，理解时间的测量方式对导航、天文学乃至日常活动等多个领域都至关重要。与时间测量相关的一个重要术语是格林威治时角，它在天体导航中发挥着重要作用。格林威治时角是指观察者的子午线与格林威治子午线之间的角度，以度为单位进行测量。这个角度有助于确定天体在天空中的位置，相对于地球的位置，尤其是对海上的导航员来说，他们依赖准确的时间记录来绘制航线。历史上，19世纪建立的格林威治标准时间（GMT）为全球时间提供了标准参考。格林威治时角与GMT直接相关，因为它允许根据太阳的位置计算当地太阳时间。当太阳在天空中达到最高点时，该地点就是正午，而格林威治时角可以用来确定当地时间与GMT相比是提前还是滞后。例如，如果一名导航员位于西经75度，则可以通过确定他们距离格林威治子午线的度数来计算他们的格林威治时角。由于地球每小时旋转15度，因此每一度经度对应四分钟的时间。因此，位于西经75度的导航员将拥有75度的格林威治时角，这转换为比GMT滞后三小时的时间差。理解格林威治时角不仅对导航至关重要，对天文学观察也同样重要。天文学家使用这个角度来追踪星星和行星在夜空中的运动。通过了解格林威治时角，他们可以预测特定天文事件的发生时间，例如日食或凌日，并相应地计划他们的观察。在现代，随着技术和GPS系统的出现，依赖于格林威治时角的必要性似乎有所减弱。然而，它仍然是天文学和导航领域的基础概念。格林威治时角背后的原理继续在学校和大学中教授，确保未来的世代理解时间测量的重要性及其与地球自转的关系。总之，格林威治时角是一个重要的概念，将计时与导航和天文学联系在一起。它展示了我们对时间的理解与天体运动之间的复杂联系。随着我们继续探索宇宙和导航我们的星球，格林威治时角提醒我们在这些努力中所需的精确性和准确性。无论我们是在海洋中航行还是仰望星空，格林威治时角始终是我们追求知识和探索的关键要素。