Sound cannot travel through a vacuum because it needs a physical medium to carry vibrations.

Sound is classified as a longitudinal mechanical wave, which means it relies on the physical interaction of particles to propagate. In a medium like air at 20 degrees Celsius, sound travels at approximately 343 meters per second as molecules collide and pass energy to their neighbors. Without these particles, the energy has no way to move from the source to a receiver.Outer space is considered a near-perfect vacuum with a density of roughly one atom per cubic centimeter in some regions. This density is far too low to support the transmission of pressure waves that the human ear can detect. Consequently, even the most violent cosmic events, such as the 1987A supernova observed by the Hubble Space Telescope, produce no audible sound in the traditional sense.To overcome this silence, NASA and other space agencies utilize the electromagnetic spectrum. Radio waves, light, and X-rays are made of oscillating electric and magnetic fields rather than vibrating matter. These waves do not require a medium and can travel through the vacuum of space at the speed of light, which is about 299,792 kilometers per second.While space is silent to our ears, scientists use a process called sonification to turn data into sound. For example, the Chandra X-ray Center has translated data from the Perseus galaxy cluster into audible tones. This allows us to 'hear' the universe by mapping visual and chemical data to specific frequencies, even though the vacuum itself remains quiet.