Mechanical waves cannot travel through outer space because they:
- A. Have low speed in vacuum
- B. Disperse in space due to long wavelength
- C. Lose frequency in the absence of air
- D. Lose transmission without interacting particles
Explanation
A mechanical wave propagates by particles of a medium pushing on their neighbours, so with no particles there is nothing to carry the disturbance and sound simply does not exist in a vacuum. Electromagnetic waves need no medium, which is why light crosses space while sound cannot. The frequency of a wave is set by its source and is not lost.