With the advancement of science and technology, human cognition of the natural world has penetrated into the world at the molecular and atomic levels. Among the many branches of natural science, astronomy has clearly become one of the most striking of them. In order to conduct scientific research on astronomical phenomena, we need a model structure that can represent these phenomena. It is because of this need that the celestial sphere came into being as an important abstract concept. This article will elaborate on the formation of the celestial sphere and its application in the field of astronomy.
1.Overview of the celestial spheres.
We stand on the earth and observe the stars in the sky, all of which seem to be equally far away from us. However, this is not the case. The distances between the stars vary significantly, and what we are observing is actually their projection on an imaginary sphere. This imaginary sphere is known as the celestial sphere, and its radius is considered to be infinite. The Earth is seen hanging from the center of the celestial sphere, which appears to revolve around it. Extending the Earth's axis of rotation in the direction of the celestial sphere gives the north and south poles of the celestial sphere. Similarly, extending the Earth's equator toward the celestial sphere gives the celestial sphere's equator. Located near the celestial North Pole, Polaris seems to remain stationary at all times, and people living in the Northern Hemisphere can use Polaris to discern their way. The height of the North Star relative to the ground depends on the latitude of the observer: in Beijing, the North Star will be due north, 40 degrees above the groundAt the North Pole, the North Star will be overhead (zenith);At the equator, the North Star lies just above the horizon. Astronomers have also divided the latitude and longitude of the celestial sphere, which are called right ascension and declination, respectively.
2.The application value of the celestial sphere.
The celestial sphere plays a vital role in the field of astronomy. Specifically, by using the celestial model, we can more intuitively and accurately depict the positions and trajectories of celestial bodies. For example, we can think of the Sun as a point on the surface of the celestial sphere, and then construct a diagram of the Sun's daily trajectory (i.e., the zodiac), and then explore the interaction and movement of the planets in the solar system.
In addition, the celestial sphere can be used as a tool for understanding the relative positions and distances between stars. Since stars can be seen by looking at their projection positions on the celestial surface, they can see their interrelationships and distances with other stars. All this is due to the fact that the celestial sphere model is not only easy to understand, but also intuitive to understand.
3.The position and direction of the celestial sphere change over time.
We know that the Earth is not stationary in space, but constantly rotates around its axis. Because of this factor, every hour when we look at the celestial sphere again, its position and direction will shift slightly, a phenomenon called "precession". In addition, the Earth is still moving around the Sun, causing the celestial sphere to shift in its viewing angle. Therefore, if we observe the celestial sphere from different locations, we will see that the same sky appears in different directions and positions.
Therefore, as a powerful and practical abstract model, the celestial sphere has a wide range of applications in the field of astronomy. It not only helps us to clarify the relative positions and distance relationships between celestial bodies, but also provides us with important tools for in-depth understanding and study of the universe. Of course, the profundity of the celestial sphere principle is not exhausted, and we may have more new discoveries in this area in the future. Therefore, in order to understand astronomy more deeply, the celestial sphere and its principles will be the knowledge base that we must master. Let's have some dry goods for the 2023 Creative Challenge