How waves travel in the universe?

How does the communication from mars to earth is possible .They didn't have any median and have they only reach to earth? Why can't we hear the sound in the universe?

Waves can be seen as the transfer of energy from one place to another.

It can happen in two ways.

1. with medium.

As the sound waves travel through air by passing energy from one atom to another atom and

2.without medium

As the light waves travels from sun to earth and it can travel in medium also. These types of waves are called electromagnetic waves. These involve vibrations of electric & magnetic fields in the space.

Waves transfer of energy in different forms (light sound water waves etc) energy is transferred in the form of electromagnetic oscillations. In light waves which do not require medium.

Sound is nothing but transfer of energy due to oscillations of air molecules so they can’t pass through space if that is the case then our ears would have been busted due to motion of heavy bodies in space.