Question

Can longitudinal waves travel without a medium?

Answer 1

Longitudinal waves need a medium to travel. This indicates that longitudinal waves cannot move through the air and solid materials and the vacuum of space. In a longitudinal wave, the medium's particles progress parallel to the wave's direction of riding.

Complete step-by-step solution:
In a longitudinal wave, the medium's particles move parallel to the wave's direction of movement. Imagine people line all holding hands. In this situation, instead of the person on the left bouncing up and down, they crash into the person next to them. Now, this following person being knocked off the balance will crash into the person near them, and so on below the line. As each person recovers their balance, they return to where they stood before being so rudely displaced.
As we can see, the wave moved from left to right again, but this time the movement of the people was also left and right. To assist us in remembering this relationship, we can imagine how the motion of the particles is along with the longitudinal wave.
While transverse waves possess crests and troughs, longitudinal waves possess compressions and rarefactions. Compression is where the wave density medium is most significant. In our line of people, this was where groups were bumping into each other. A rarefaction is where the wave medium density is the lowest. In our line, this happened just after the compression, where the characters were spread out, deciding to recover their balance.
Similar to the wavelength of a transverse wave is the length from crest to crest or trough to trough, the longitudinal wave's wavelength is the length between compressions or between rarefactions.
No, longitudinal waves cannot travel without a medium.

Note: Light and other kinds of electromagnetic waves are supposed transverse waves. These waves move through a vacuum as they do not require a means for their propagation. Longitudinal waves such as sound cannot move through the vacuum as they require a medium to progress.