Some planets, like Mars and Venus, do have atmospheres, which means sound can travel. However, the way sound behaves there is very different from what we experience on Earth. On Mars, the thin, cold atmosphere makes voices sound higher and more hollow.
“On Mars, your voice would sound tinny and hollow, like the sound of a piccolo,” the professor notes. On Venus, the dense atmosphere causes sound to slow down and deepen. “On Venus, the pitch of your voice would be much deeper, like the sound of a booming bass guitar.” These differences are due to the structure and pressure of the planets’ atmospheres.