Final answer:
The atmosphere is transparent to visible light, which allows it to pass through without being significantly absorbed or scattered, enabling clear visibility of celestial bodies from Earth.
Step-by-step explanation:
The atmosphere is transparent to visible light. This means that visible light can pass through the Earth's atmosphere without being absorbed or scattered significantly, allowing us to see the Sun and other stars from the Earth's surface. Materials, like certain types of glass, are transparent because they do not have energy levels that would absorb visible light; individual photons interact with individual atoms without being absorbed, unless they reach an energy step large enough, which visible light does not have. However, higher energy light like UV, x-rays, and gamma rays do get absorbed because their photon energy is sufficient to ionize the material.