行星
How to Understand
行星 (xíng xīng) refers to a celestial body that orbits a star, is spherical in shape, and has cleared its orbital path of other debris. Unlike stars, planets do not emit their own light but reflect the light of their star. This term is commonly used in astronomy and science.
The character 行 (xíng) originally meant 'to move' or 'to go,' and later came to mean 'a system' or 'a course.' 星 (xīng) means 'star.' Together, they form a term that literally translates to 'moving star,' reflecting the ancient observation that planets appear to move across the night sky relative to fixed stars.
行星 is widely used in scientific discussions, educational materials, and space-related contexts. It is also a common term in popular culture, such as in science fiction or documentaries about the solar system. Understanding this word is essential for anyone studying astronomy or space science.