Greenwich sidereal time

简明释义

格林恒星时格林尼治恒星时

英英释义

例句

1.The satellite's orbit was planned according to Greenwich sidereal time to ensure it passes over the same point on Earth at regular intervals.

卫星的轨道是根据格林威治恒星时间规划的，以确保它在固定间隔内经过地球上的同一点。

2.When tracking distant galaxies, astronomers often refer to Greenwich sidereal time for precise timing.

在追踪遥远的星系时，天文学家通常参考格林威治恒星时间以获得精确的时间。

3.Navigators use Greenwich sidereal time to determine their longitude while at sea.

航海者使用格林威治恒星时间来确定他们在海上的经度。

4.The astronomer calculated the position of the stars using Greenwich sidereal time, which is essential for accurate celestial navigation.

天文学家使用格林威治恒星时间计算星星的位置，这对准确的天文导航至关重要。

5.In order to coordinate observations, we need to convert our local time to Greenwich sidereal time.

为了协调观测，我们需要将当地时间转换为格林威治恒星时间。

作文

Understanding time is crucial for navigation, astronomy, and even our daily lives. One of the most important concepts in the realm of timekeeping is the Greenwich sidereal time. This term refers to the time standard based on Earth's rotation relative to distant stars rather than the Sun. Unlike solar time, which is affected by the elliptical shape of Earth's orbit and its axial tilt, Greenwich sidereal time provides a more stable reference point for astronomers and navigators alike.The concept of Greenwich sidereal time originates from the Prime Meridian, which is located at Greenwich, London. The Prime Meridian serves as the zero-degree longitude line, and it is from this point that all time zones are calculated. Sidereal time itself is based on the rotation of the Earth with respect to fixed stars. A complete rotation takes approximately 23 hours, 56 minutes, and 4 seconds, which is slightly shorter than the solar day. This discrepancy arises because while the Earth rotates on its axis, it is also moving along its orbit around the Sun.For astronomers, understanding Greenwich sidereal time is essential for locating celestial objects in the night sky. When an astronomer wants to observe a star or planet, they need to know the exact time in sidereal terms to accurately point their telescopes. Each hour of sidereal time corresponds to about 15 degrees of celestial longitude. Therefore, knowing the Greenwich sidereal time allows astronomers to predict when specific celestial events will occur, such as the rising and setting of stars.In practical terms, Greenwich sidereal time is often used in conjunction with Universal Time (UT). While UT is based on the average solar time at the Prime Meridian, Greenwich sidereal time is adjusted to account for the Earth's rotation relative to the stars. This adjustment is vital for precise astronomical calculations, especially when planning observations or launching satellites. For instance, when a satellite is launched into orbit, mission planners must calculate the Greenwich sidereal time to ensure the satellite's trajectory aligns with specific points in space.Moreover, Greenwich sidereal time plays a role in navigation. Historically, sailors relied on the stars for navigation, and understanding sidereal time was crucial for determining their position at sea. By comparing their local time with Greenwich sidereal time, navigators could ascertain their longitude, which is critical for accurate navigation across vast oceans.In conclusion, the concept of Greenwich sidereal time is fundamental to both astronomy and navigation. It provides a consistent framework for measuring time based on the Earth's rotation relative to distant stars. As we continue to explore the universe and navigate our world, the significance of Greenwich sidereal time remains ever relevant. Understanding this concept not only enhances our knowledge of timekeeping but also enriches our appreciation of the cosmos and our place within it.

理解时间对导航、天文学甚至我们的日常生活至关重要。在时间计量领域，一个重要的概念是格林威治恒星时。这个术语指的是基于地球相对于遥远恒星的旋转而非太阳的时间标准。与受地球轨道椭圆形状和轴倾斜影响的太阳时不同，格林威治恒星时为天文学家和导航员提供了一个更稳定的参考点。格林威治恒星时的概念起源于位于伦敦格林威治的本初子午线。本初子午线作为零度经线，从这一点出发，所有的时区都被计算出来。恒星时本身是基于地球相对于固定恒星的旋转。一次完整的旋转大约需要23小时56分钟和4秒，这比太阳日稍短。这种差异产生的原因在于，当地球绕其轴旋转时，它也在围绕太阳的轨道上移动。对于天文学家而言，理解格林威治恒星时对于在夜空中定位天体至关重要。当天文学家想要观察一颗星星或行星时，他们需要知道确切的恒星时间，以准确地指向他们的望远镜。每个恒星时间的小时对应大约15度的天体经度。因此，了解格林威治恒星时使天文学家能够预测特定天文事件的发生，例如星星的升起和落下。在实际操作中，格林威治恒星时通常与世界协调时间（UT）一起使用。虽然UT基于本初子午线的平均太阳时间，但格林威治恒星时经过调整，以考虑地球相对于恒星的旋转。这种调整对于精确的天文计算至关重要，尤其是在计划观测或发射卫星时。例如，当卫星被发射到轨道时，任务规划者必须计算格林威治恒星时，以确保卫星的轨迹与太空中的特定点对齐。此外，格林威治恒星时在导航中也发挥着作用。历史上，水手依靠星星进行导航，理解恒星时间对确定他们在海上的位置至关重要。通过将他们的地方时间与格林威治恒星时进行比较，导航员可以确定他们的经度，这对在辽阔海洋中进行准确导航至关重要。总之，格林威治恒星时的概念对天文学和导航都是基础性的。它提供了一个一致的框架，用于根据地球相对于遥远恒星的旋转来测量时间。随着我们继续探索宇宙和导航我们的世界，格林威治恒星时的重要性依然相关。理解这个概念不仅增强了我们对时间计量的知识，也丰富了我们对宇宙及其在其中位置的欣赏。