Stars do emit radio waves, but these waves do not expand in the same way as, for example, sound waves. Radio waves are a form of electromagnetic radiation, similar to visible light, but with longer wavelengths.
When a star emits radio waves, they travel through space in a straight line, spreading out as they move away from the source. However, unlike sound waves that expand in a spherical pattern, radio waves maintain their intensity over vast distances, as long as they are not absorbed or scattered by interstellar matter.
The radio waves emitted by stars can be detected on Earth using radio telescopes. These telescopes are designed to receive and amplify radio signals, allowing astronomers to study and analyze the properties of celestial objects emitting radio waves, including stars.
It is worth noting that the radio waves emitted by stars are typically very weak compared to other sources of radio waves in the universe, such as pulsars, quasars, or galaxies. This is because stars emit radio waves primarily through thermal processes, where the radio emission is a result of the heat generated within the star's core.
While the radio waves from individual stars can be detected and studied by radio telescopes, distinguishing the radio waves from individual stars among the vast number of radio sources in the universe can be challenging. Radio telescopes collect signals from various celestial objects simultaneously, and it requires careful analysis and processing to identify and separate the signals coming from different sources.
However, with advanced techniques and data processing methods, astronomers are able to differentiate and study the radio emissions from individual stars, contributing to our understanding of stellar properties and processes.