Sound requires a medium (air, water, or solid) to propagate. In a vacuum, there are no particles to transmit vibrations. This means that sound cannot travel through space since space is a vacuum with no air or other substances to carry sound waves. That’s why astronauts in space can’t hear each other unless they use radios, which transmit signals as electromagnetic waves instead of sound waves.
On Earth, sound moves by making particles vibrate and pass energy along, like a ripple in a pond. Sound moves at about 343 m/s in air, but it travels faster in water and fastest in solids because the particles are packed closer together. That’s why whales can communicate over long distances underwater, and why you can hear a train coming by pressing your ear to the tracks before you hear it through the air.
Since there are no particles in a vacuum to carry these vibrations, sound simply has no way to move. This differs from light, which can travel through space because it moves as electromagnetic waves that don’t need a medium. This explains why we can see the Sun but not hear anything from it!
