[neilep (OP)]

Dearest Vacuumed Packed  Lufflies ,


See this Vacuum ?

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Nice eh ?  *sheepy gets tapped on shoulder*

"what's that ?.......oh......I see......DOH !"

I'm reliably informed that I mean THIS kind of vacuum !!

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So, I take this Vacuum chamber and silly me goes and explodes a star inside it like this one !


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Nice eh ?...Being delivered Tuesday !


Now then (finally !!)....as ewe all know...sound does not exist in a vacuum......so..what happens to the energy of my exploding star that would have produced the sound if there had been a whole bunch of air for it to exist in ?

Lets sit down, do lunch and find the answer....cos I don't know it.....do ewe ?


whajafink ?



Neil
Sound Enquirer (but not of sound mind !)

[lyner]

Sound is what you hear when the air in between you and the source vibrates.
An explosion in air will produce a sudden increase in pressure which pushes air outwards. Once the explosion runs out of energy, the atmosphere will 'push back'  and  fill the space it came from. But, it's launched a pressure wave (an impulse) - traveling outwards carrying energy with it. This wave will keep going long after the actual air has stopped moving outwards and sloshed back. The sound becomes quieter as it spreads out and the initial sharp pulse will be modified into a characteristic 'boom' as the different frequencies in the initial pulse are spread out in time (dispersed) because of their different speeds.

In space, the material of the explosive will keep moving outwards without being pushed back by any air pressure.
When it hits your space ship it will bash into the sides which will then sound like 'sound' to the crew - transmitted through the air inside. Because there will be a range of speeds of the particles flying outwards, the sound that is heard will be spread out but probably it wouldn't sound the same as a distant explosion in air.
If it's a Star exploding, if it is not so close as to take you out completely you would probably experience a gentle acceleration as the body of particles arrives and the particles hit the sides one by one. The first ones to arrive will be so fast (approaching c) that they will go straight through the ship and possibly do you some damage as they interact with the metal parts and produce gamma rays and stuff. You would finally end up 'surfing' on the wave of particles.
Of course, if you have your force field screens turned on you wouldn't hear a thing.

[neilep (OP)]

Just look at the above post will ya ?

I ask a simple question and along comes a fantastic reply !.....all you peeps out there who aren't members yet really ought to join up right now and avail yourself of these incredible resources !  (LOL..I am NOT on any sort of commission but I do truly appreciate the time and effort people put into answering the questions here)

THANK EWE SophieCentaur....

......so...the energy is there........it just eventually gets used up by not becoming sound and eventually just dissipates.....The fact that air exists in other circumstances just gives energy an excuse to provide a sound eh ?....

[lyner]

If it sounds like sound, it's sound.
That's a sound statement.

[LeeE]

Sound is a pressure wave travelling through a physical medium - if there was enough matter surrounding the star to consititue a medium then it would make a sound.  Mind you, you probably wouldn't be able to hear it because the frequencies would be all wrong for us humans, plus we'd somehow need to couple our eardrums to the medium that's being 'waved'.  There are some nice Hubble pics that show shockwaves from later stages of star exlosions passing through matter cast off during the earlier stages, and when you look at them you're seeing a 'sound' wave from an exploding star.

[neilep (OP)]

Fantastic post.

THANK EWE LeeE.

My original premise was that without the medium to make the sound there would be an excess of energy......ie: the energy that would create the sound....but with yours and Sophiecentars assistance I now understand the nature of it.

I will seek out the photos you cite.....I reckon they'll make good Science Picture posts.

THANK YOU

[qazibasit]

well i think it dissipates into the vaccume in the form of energy or they may change their form and convert into different waveform.

[neilep (OP)]

well i think it dissipates into the vaccume in the form of energy or they may change their form and convert into different waveform.

Thank ewe qazibasit

Fascinating stuff and I appreciate your answer.