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Sound Waves in Outer Space

  1. Jul 12, 2005 #1
    This might be a silly question, but i just realized i don't really know why we don't hear the sound of explosions from the Sun.

    Well, we do know there is "almost" noting in outer space. But there still is not much resistance + matter for the oscillations to reach Earth.
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  3. Jul 12, 2005 #2


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    Sound waves are mechanical pressure waves carried though relatively dense materials. On the scale of things our atmosphere qualifies. The void of outer space does not. Sound waves need a medium, they have no medium in space. Sorry, there are no sound waves in space.
  4. Jul 12, 2005 #3


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    What oscillations ?
  5. Jul 12, 2005 #4
    i mean vibrations - oscillations..

    I don't understand that concept really. What does there is "noting" mean?

    The soundwave is in fact the vibration of matter at given density to be plain.
    But i am talking about a solar explosion..The explosion should release some matter from "Sun". (Solar Flares sometimes millions of kilometers long)

    If there were absolutly noting in space then they would travel quite fast with their given Velocity and hit the earth's atmosphere. So cause vibrations within planet earth causing some kind of voice-sound.

    Anyway i can think of it like this; any atom on the way towards earth hits another atom, it would just share some of its velocity or stop and send the other atom towards its vectoral speed. Noting changes, matter should reach earth and share their Velocity to cause vibrations within Earth's atmosphere creating some kind of a sound.

    Maybe the sound is lost within the atmosphere, hmm thats more logical..
  6. Jul 12, 2005 #5


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    No, it is more logical that only electromagnetic energy can propagate through the regions of space with EXTREMELY low atomic density. When there is less then 1 atom per cubic meter there is little or no possibility for collisions to occur. Pressure waves can only propagate when there is a medium to carry (ie collisions) them. The interplanetary regions of the solar system do not have a high enough atomic density to carry pressure waves.
  7. Jul 12, 2005 #6
    I do understand, and have kinda guessed that it is almost empty.

    But what i am suggesting is;

    We should not need collisions for the sound to reach Earth, the source matter will reach planet's atmosphere by their velocity given by the explosion(Solar Flare)..Therefore the vibrations would occur here not in outerspace..

    Well, to explain this simply, think about two identical iron spheres which are hanged to the same iron bar. You pull one up on the air, and release it.

    Now, are we going to ignore that the released sphere is going to hit the sphere that is at rest sooner or later? And say "No it won't affect the other sphere there is a space between them?"

    And remember in this example, there is resistance (air) between two iron spheres, while there is almost noting in outer space(you said that). And noting that would stop the matter that escaped Sun's gravity and travel towards planet Earth.
  8. Jul 12, 2005 #7


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    It seems you do understand that explosion does not get transmitted from the sun to the earth by sound waves. In fact, these explosions (solar flares) do cause effects on earth. We get a shower of charged particles that disrupt radio communication and I think also it can initiate lightning. If you are expecting an explosive noise, though, you will be disappointed. The constituents can cause a sound wave in a dense medium because they cause a pressure wave because they are all in a sense "in phase", since they start at the same moment. The explosive products hitting the earth, however, all hit at different times, generating no coherent sound wave.
  9. Jul 12, 2005 #8
    I would say the void called outerspace depends on a -transversal- of energy between 2 points where the distance is very large. Indicating that first the work it would require to carry over the distance would have to be great to jump the -void- . The second thing I would like to mention is the effect that mass and energy is completely smeared in space where energy is the only form of matter which can transgress. Energy is in effect the work of mass over distance D.(explaination below)

    Distance is dependant on [velocity X mass]

    Mass X velocity X distance = energy
    suprisingly velocity is a constant as to energy that inacts a existance
    because without velocity there would not be a time factor. The actual text book name for energy derives a context of actual WORK divided by TIME which is why you pay your electric bill, and about the only reason why.

    When PE reaches a criticality, it is displaced by the electrical effect of work, aka what I call energy. Nuclear reactors and electric, sun-planets and gravity, etc

    As for the sound of an exploading sun.... it could be as faint as a whimper over distance D. Now this is where impulse and momentum come into pla - equilibrium between Point A and point B.

    Force X {delta Time} = M X {delta Velocity}

    The likelyhood of this equation suggests that the end result will have to be a change in the velocity of some other mass. Also divide each side by distance because anything dealing with time or velocity has to occur over some distance.
  10. Jul 12, 2005 #9

    Sounds interesting. So if they did reach in phase, we would here a large explosion!

    Anyways, I have one more point for consideration.

    Everyone has noticed that if you swing a stick in air, you get a whooshing sound. This sound definitely comes from the disturbance caused by the stick in the air. But whatever velocity you give to the stick, a small baby can produce a louder sound than that 'whooshing' just by some small vibrations in his vocal chord. Why does this happen is a valid question, but knowing that this happens, we can analyse the 'sound from the sun' situation.
    The particles from the sun reaching the earth can collide with the particles in the atmosphere to produce sound, but this will be similar to the swing-a-stick-phenomenon and not to the baby-using-his-vocal-chord-phenomenon. So the sound won't be audible. Any comments?
  11. Jul 13, 2005 #10
    mechanical wave??

    i do not think that the sound being too "feeble" wud be a bone of contention coz sound waves are mechanical rite?? they need a material medium to progress...whats making u guyz think that sound waves DO reach the earth in the 1st place??
  12. Jul 13, 2005 #11
    I recall reading that in the early universe, about 1 million years after the Big Bang, the density was high enough to propagate pressure waves. The evidence of the pressure disturbances appears in the CBR as regions of high and low density. The sound waves would have lowered in frequency over the eons just as did the EM radiation due to the expansion of space.

  13. Jul 13, 2005 #12


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    Atoms from the Sun pelting our atmosphere one-by-one does not constitute 'sound'.

    A single movement of an atom (or even many atoms) is not sound. Sound requires *regular, repeated* movements which come from jostling back and forth and back and forth. The number of repeats per unit time creates the frequency of the sound. An atom's single movement (or many atoms' single movements) has a frequency of *zero*.

    Sound can only happen in a medium that is dense enough to *maintain* these "jostllations".
  14. Jul 13, 2005 #13
    Can we make an experiment like this?

    Create a room in outer-space, 2-2 meters..Put a plate on the side of the Sun, from that plate when a solar flare occurs on Sun, We would watch the vibrations
    with a computer or something..

    What i am suggesting is there should be vibrations..It is irrelevant if we can hear
    or not at this point, the point is can any device detect this....

    And omg no i am not expecting a "KAboom" you know with "Background Noise" scientists do not mean hearing the "BANG" of the Big Bang :surprised
  15. Jul 13, 2005 #14


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    Exec, this question has been answered by krab. Solar flares can be detected at the upper atmosphere.
  16. Feb 21, 2011 #15
    would like to add that unless there is some sort of wave propogation in a medium not a vacuum you cannot have sound. Also the solar flares enter our atmosphere as electromagnetic radiation or light. there speed is the speed of light and not the speed of sound. thus energy= mc^2
  17. Feb 21, 2011 #16
    This thread has been dead for five and a half years and the OP is no longer registered. Check the date of the last post before responding.
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