Longitudinal Waves Question

1219269

Just a quick question: Why can't longitudinal waves travel through space?

I've done some google searches but the answers lack any kind of clarity and seem to be written by 10 year olds for 10 year olds :/ I'm looking for in particular why they can't, yet transverse waves can! Thanks in advance :smile:

Reply 1

Stonebridge

Apart from light (which can be considered as photons) which transverse waves are you thinking of that can travel through space?

Reply 2

Joinedup

Original post by Audi

by space are we talking about vacuum?

is travelling through vacuum a general property of transverse waves do you think or is it specific to some waves and not others?

some transverse waves
pond ripples - can they go through a vacuum i.e. if you take the water away?

transverse wave in a slinky spring - do they go through a vacuum i.e. if you take the slinky away?

maybe if you ask google a more tightly defined question you'll get a more satisfactory answer.

Reply 3

1219269

Original post by Stonebridge

Apart from light (which can be considered as photons) which transverse waves are you thinking of that can travel through space?

Well I was originally thinking gamma vs sound, why exactly can't sound travel through a vacuum. :smile:

Reply 4

1219269

Original post by Joinedup

Yes, a vacuum.

I'm not gunna lie I don't really understand what you're getting at :/ Yes I've tried several differently worded questions but to no avail unfortunately :frown:

Reply 5

hprynne

Original post by Audi

Longitudinal waves need a medium to compress. The particles are pushed and pulls to form areas of compression and rarefraction. However in a vacuum this is not possible as it is empty - no medium - no particles!

Hope this helps, :smile:

Reply 6

1219269

Original post by hprynne

hey yeah this is what I'm looking for thanks, one quick question if I may, surely that means that transverse waves suffer the same issue?

Reply 7

Stonebridge

Original post by Audi

Well I was originally thinking gamma vs sound, why exactly can't sound travel through a vacuum. :smile:

The reason sound can't travel through a vacuum is that sound needs a medium (solid, liquid or gas with real vibrating molecules) and not because it is a longitudinal wave. Any wave which is made up of a mechanical oscillation, and this is the case for sound waves and water waves, needs some material to vibrate. A vacuum is, by definition, no material. So there is nothing to vibrate. It doesn't matter if the wave is transverse or longitudinal, if it is a mechanical wave it will not travel through a vacuum.

Light is very special. It is not a mechanical wave. It is an electromagnetic wave. It does not need a medium. The fact that it behaves like a transverse wave does not logically imply that transverse waves can travel through a vacuum but longitudinal can not.

Reply 8

hprynne

Original post by Audi

hey yeah this is what I'm looking for thanks, one quick question if I may, surely that means that transverse waves suffer the same issue?

To be honest, I am not entirely sure... However, I think it's due to the way energy is transferred. Due to the perpendicular movement of transverse waves, they can transfer matter using tiny electric/magnetic fields, unlike longitudinal waves which need vibrating matter. I'm basing the above on internet research, but I guess it makes sense.. Sorry if this isn't much use!