Final answer:
Radio waves interact with Earth's atmosphere in various ways: FM and TV waves travel through easily, while AM and low-frequency radio waves can be absorbed or reflected by the ionosphere. The detection of cosmic radio waves is important in astrophysics, despite challenges from electromagnetic pollution.
Step-by-step explanation:
The behavior of radio waves when transmitted from one point on Earth to another, or when interacting with different parts of the atmosphere, can vary depending on their wavelengths. FM and TV waves pass relatively easily through the atmosphere because they are not substantially absorbed. In contrast, AM radio waves can be affected by the ionosphere, which is a layer of charged particles at the top of our atmosphere. The ionosphere can absorb or reflect AM radio waves due to its interaction with sunlight and charged particles from the Sun. Low-frequency radio waves are also blocked by the ionosphere, as indicated in Figure 5.6 that illustrates Earth's atmosphere and the transmission of the electromagnetic spectrum.
Furthermore, the behavior of radio waves has significant implications for astronomy and astrophysics. Karl G. Jansky's discovery in the early 1930s that cosmic radio waves are detectable from Earth's surface has opened up paths for understanding the universe. However, due to the increasing use of radio-wave frequencies by everyday gadgets and communication systems, astrophysicists now face challenges with electromagnetic pollution, necessitating strict regulations to prevent interference between various electromagnetic signals.