In space, radio waves travel through the electromagnetic field. The electromagnetic field is a fundamental physical entity that permeates all of space and is composed of electric and magnetic fields oscillating in harmony. When a source, such as a radio transmitter, generates oscillating electric currents, it creates electromagnetic waves.
These electromagnetic waves, including radio waves, do not require a physical medium like air or water to propagate. They can travel through the vacuum of space without the need for a material carrier. This is because electromagnetic waves consist of oscillating electric and magnetic fields that self-propagate, meaning they can continue their motion through space indefinitely.
The behavior of radio waves in space is similar to other types of electromagnetic waves, such as visible light, X-rays, and gamma rays. They all propagate through the electromagnetic field and can travel vast distances across space, allowing for long-range communication and the study of distant celestial objects.
When we receive radio signals from space, such as those emitted by stars or distant galaxies, those signals have traveled through space as electromagnetic waves until they reach our receivers on Earth. By studying these radio waves, astronomers can gather information about the objects that emitted them, their properties, and their distance from us.
To summarize, radio waves in space are carried by the electromagnetic field, which permeates the vacuum of space and allows electromagnetic waves to propagate without the need for a physical medium.