Sound waves cannot travel through the vacuum of space, which is why an explosion on Mars would not be heard on Earth. While Mars has a thin atmosphere that allows sound to propagate locally, the interplanetary space between the two planets is nearly a perfect vacuum. Therefore, the answer to how long sound waves take to travel from Mars to Earth is effectively zero seconds, as they cannot travel at all. The discussion clarifies that sound requires a medium to propagate, and space does not provide that. Ultimately, sound from Mars cannot reach Earth due to the lack of a transmission medium.
