Couple questions regarding vacuum of space

[PistolPete38]

My first question is basically does a vacuum work in space. For example: You are traveling through space and pass through a cloud of dust, could you take a sample of the dust cloud with a vacuum or would nothing happen?

 

My second question involves sound in space. Now i know you can not hear sound in a vacuum but does a vacuum effect sound waves. For example: if a focused wave of sound designed to shatter stone on earth, would it work in space? Would there need to be changes to the wavelength for it to work in a vacuum? Any help to settle my curiosity would be appreciated .

[Klaynos]

If you created a vacuume with a density lower than the area of space with the cloud in then I suspect it would work.

 

The gap between particles in space is too grate for longitudinal (sound) waves to be passed efficiently from one to another, therefore the wave would not work in space as they require a relatively dense substance (such as air or even better stone) to travel.

[Sisyphus]

A vacuum cleaner would not work in space. How they function is by blowing air away from the intake, thus reducing the air pressure there. The weight of the atmosphere then makes the surrounding air rush in to compensate for this loss of pressure, creating what looks like a "sucking" effect. However, the source is not some sucking power of the vacuum, but rather a pushing of the surrounding atmosphere. If there's no air pressure (like in space), nothing happens.

 

Sound also does not work in space, because sound waves are waves of pressure through some medium, like air. Something vibrates, which push on surrounding molecules, which in turn push on the molecules surrounding them, and so the vibration travels until it pushes on your eardrum, which your nerves sense and your brain interprets as sound. In space, there is no medium through which the vibration can travel, and so there is no such thing as a sound wave in space.

[swansont]

In space no one can hear you scream. Or tidy up, for that matter.

[insane_alien]

We have never been able to make a vacuum as good as the one in space never mind a better one. its simply too hard with outgassings from the chamber walls etc. the pressure differential, even if we made a complete vacuum(which is impossible), would be absolutely tiny. i'm talking on the order of pico(10^-12)pascals. no gaseous/dust movement into the sample chamber would be seen as the external pressure would be unlikely to force particles into the sample chamber.

[5614]

Space is a vacuum, and in the vacuum is the solar system, galaxy and entire universe... some vacuum!

[gcol]

Space is a vacuum, and in the vacuum is the solar system, galaxy and entire universe... some vacuum!

 

I like that.

Space is not homogenous throughout. Surely It is quite possible that in some areas of space, the "vapour density" is high enough that sound might propagate?

[gcol]

I pulled this quote from Science Week. Does this cause any second thoughts about the possibility of certain frequencies/energies of sound to propagate through certain "densities" of vacuum?

 

If I have committed some error of etiquette when quoting, please forgive and explain. I am a newboy to forums. I have underlined and emboldened the part which seemed to have particular significance:

 

 

3) The semantic incongruity, however, like the sublimated worries about modern life that give us science fiction nightmares, belies something important -- unfinished business of the 1970s that has been slowly and systematically tearing physics apart. Stripped of their confusing mathematical descriptions, the phases of the vacuum boil down to physical analogies with phases of ordinary matter, natural phenomena observed to exhibit universality. That means that their properties at long length and time scales, where we normally do experiments, do not depend on microscopic details at all, and thus do not constrain them when measured. A simple example of emergent universality would be sound propagation in fluids and solids, an effect perfectly well accounted for as the motion of atoms, but also a generic property of the phases not requiring atoms to make sense. Sound is an especially pertinent example because it has a second identity at low temperatures as an emergent elementary particle with properties identical to those of particles of light. Insensitivity to microscopic detail thus turns the concept of fundamental on its head, in that it makes principles of self-organization the truly important thing, rendering the quantum underpinnings of the Universe, whatever they are, unknowable in the absence of experiments that reach shorter scales and irrelevant to behavior we presently see. Little wonder that physicists remain bitterly divided over full acceptance of the vacuum as a phase.

References (abridged):

 

1. Akira, 124 min, directed by Katsuhiro Otomo (Kodansha Ltd., Japan, 1988)

 

2. S. Weinberg, The First Three Minutes: A Modern View of the Origin of the Universe (Basic Books, New York, 1994)

 

3. M. Rees, New Perspectives in Astrophysical Cosmology (Cambridge Univ. Press, Cambridge, 2000)

 

4. A. H. Guth, A. P. Lightman, The Inflationary Universe: The Quest for a New Theory of Cosmic Origins (Perseus, New York, 1998)

 

5. M. E. Peskin, D. E Schroeder, An Introduction to Quantum Field Theory (Westview, Boulder, CO, 1995)

 

Science http://www.sciencemag.org

[5614]

I like that.

Space is not homogenous throughout. Surely It is quite possible that in some areas of space' date=' the "vapour density" is high enough that sound might propagate?[/quote']

It's all probabilities... theoretically it is possible that such a thing could happen. Even given the size of the universe it is still unlikely, but nothing says it couldn't happen.

[doG]

My first question is basically does a vacuum work in space.

No. A vacuum is simply the absence of atmospheric pressure. Once you're done to 0 PSIA, the pressure in space, that's as low as it gets.

[insane_alien]

Space isn't a complete vacuum. there is around 10-12 atoms per m^3 in the solar system, less in interstellar space and around 3-4 in intergalactic space. In nebulae it can go as high as 100 atoms/molecules per m^3 at this low density it reall doesn't behave like a gas as the mean free path is practically infinite.

 

gcol that article is refering to sound waves propogating through a medium(probably a crystal as i have seen numerous articles on this and they all mention crystals) where the sound wve exibits a particle nature much like the particle behaviour of light. instead of being called a photon it is called a phonon. however these still need a medium to propogate.

[gcol]

5614 and Alien

 

Thanks for you considered responses re. sound propagation through vacuum.

Does that imply that "Does sound travel through vacuum?" should be answered with "What type of sound, and what degree of vacuum?

 

Would a refinement of the term vacuum be useful? 0 p.s.i.seems rather cumbersome and vague in this context (Sorry, Dog). Perhaps something like zero kelvin, theoretically possible, yet impossible to attain. Then again, perhaps there ought to be more than one type of vacuum....one free of matter, one free of energy, both possible as theoretical limits.

 

Vacuum cleaner in space

 

The earthly vacuum cleaner depends upon the impact of the impeller upon individual molecules (of gas or dust) The lower the gas/dust density, the lower the lower the efficiency. Efficiency will tend towards zero, but in a non-perfect vacuum, can it ever reach absolute zero?

 

For a space "vacuum cleaner", Why not consider an electrostatic "suction device", rather than wallopping dust and molecules with a rotating stick?

 

Come to that, even a solar sail and a radio aeriel have been designed to suck up/collect something specific. You could say they wouldn't work, or be zero efficient in the absence of photons or radio waves. Horses for courses.

[insane_alien]

Does that imply that "Does sound travel through vacuum?" should be answered with "What type of sound, and what degree of vacuum?

 

The what degree of vacuum part; Yes. The what type of sound part; No.

[5614]

Sound will not travel through a vacuum, what I was saying was that space isn't a proper vacuum (ie. there are bits of matter within it) and so if on the very improbable chance enough of this matter gathered in one place then sound would travel through this area of matter.

 

What you need to understand is that a sound wave through air is when the air molecules vibrate and sound travelling is those vibrations being passed along to the next atom, ie. 1st atom vibrates and hits 2nd atom - now 2nd atom is vibrating and passes it onto the 3rd, and this happens extremly quickly (the speed of sound).

 

If there are no atoms there is no sound and then obviously it can't be passed along either.