In space, there is no medium for sound to propagate, such as air or water. Sound waves require a medium to travel through, as they rely on the vibration of particles in that medium. Since space is a vacuum with no particles, sound cannot travel in the same way it does on Earth or in other mediums.
On Earth, the speed of sound depends on various factors, primarily the properties of the medium through which it travels. In dry air at sea level and at a temperature of around 20 degrees Celsius (68 degrees Fahrenheit), the speed of sound is approximately 343 meters per second (about 1,125 feet per second).
Therefore, the main difference between the speed of sound in space and on Earth is that sound cannot propagate in the vacuum of space, whereas on Earth, sound requires a medium like air or water to transmit vibrations and travel.