Radio waves can theoretically travel indefinitely through space without losing all their energy. In the vacuum of space, radio waves experience minimal attenuation or loss of energy due to the absence of a medium to absorb or scatter them. This means that radio waves can propagate across vast distances, potentially traveling across the universe.
However, it's important to note that even though radio waves can travel great distances, they can still experience a decrease in signal strength over long distances due to factors like free-space path loss. Free-space path loss is the gradual reduction in signal strength as the radio waves spread out over distance. The intensity of the signal diminishes with the square of the distance from the source.
Furthermore, as radio waves propagate through space, they may encounter other forms of interference or obstacles that can attenuate or distort the signal. These could include cosmic noise, interstellar medium, and other celestial bodies. These factors can affect the quality and reliability of the received signal.
In summary, while radio waves can travel vast distances through space, their signal strength can weaken due to factors such as free-space path loss. However, they don't completely lose their energy, and their propagation is limited mainly by the ability to detect and decode the weak signals over long distances.