Have you wondered ever – how we can speak and listen? Can there be sound in space? Can we hear in space?
It looks so natural to us that we don’t question why we are able to do this marvellous feat every day. Are we ignorant? I believe, No. Then, do we think it is too complex not to ponder the attention, No? Then what is the reason, we are caught up in so many activities and earning our livelihood that we forget to ask questions.
Let’s see – sound mechanism
Sound needs a medium because these are propagated through the disturbance in the matter (air particles). On the other hand, there is the vacuum in space i.e there is no material medium. We are not totally true here, there is a presence of particles in space but that is very less dense and sparse. Due to this, particles don’t transfer their movements (disturbance) to other particles. That’s the reason, natural speaking and listening are very very difficult.
How do they do it then?
An astronaut can only talk using radio communication systems involving a transmitter and receiver placed in their suits. This system works on radio waves which are EMW (Electromagnetic Waves) which can travel through the vacuum. No need to fear from the term EMW, it is the name given to the range of vibrations (cosmic rays to microwaves) which doesn’t need any material to travel. Vibration is a disturbance in something (to and fro), see the figure below for an example. The rope is moving from its position due to pulling and coming back, you can see the disturbance/wave travelling.
Space suit and its value
Coming back to the topic, using this system, sound signals can be transmitted as radio waves which can be directed as desired. There is no atmosphere outside an astronaut’s space suit when he is outside in space. They can’t simply go out and talk to each other (we will cover it in another post). Astronaut’s space suit also maintain atmospheric conditions for the astronaut.