You are correct that sound waves require a medium, such as air or water, to travel through. In the vacuum of space, where there is no atmosphere, sound cannot propagate as it does on Earth. Therefore, we cannot directly "hear" anything from outside our solar system in the traditional sense.
However, scientists have found other ways to detect and study distant celestial objects. They use various instruments and technologies to observe electromagnetic waves, which include visible light, radio waves, X-rays, and more. These waves can travel through the vacuum of space and provide valuable information about astronomical phenomena.
For example, radio telescopes are used to detect and study radio waves emitted by celestial objects. By analyzing the radio signals received from distant sources, scientists can learn about the composition, temperature, and other characteristics of those objects. Similarly, optical telescopes capture and analyze visible light to gather information about the properties of stars, galaxies, and other astronomical bodies.
While we cannot directly hear sounds from space, the exploration of the cosmos relies on other methods of observation and data collection to expand our understanding of the universe.