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The Scream Aliens Hear From the Earth
onehitwonder writes "Astronomers have discovered that the Earth emits awful, ear-piercing chirps and whistles that could be heard by any aliens who might be listening, according to an article up at Space.com. The sounds are created by charged particles from the solar wind colliding with Earth's magnetic field. This article explains more about the sounds and links to an audio recording of it."
Animals (which includes us, and likely the aliens) can't... machines can, sound travels basically the same "out there" as it does in here, its just there isnt enough particles to produce a wave large enough for our ears to detect...but anyways, assuming that aliens are listening, would generally imply they had the technology to do so, rather than just sticking an ear out.
aurora recordings on earth is known many years already. even when you can't see auroras, you can hear them in VLF range. for example http://www-pw.physics.uiowa.edu/mcgreevy/
I'm afraid that's not true. Assuming that a sound wave could travel (particle to particle) in a gas density like that of outer space (1x10^-11 Pa), quantum effects would completely destroy any signal contained years before one particle could collide into the next.
The problem with this is, the "scream" a planet produces is insignificant to the SCREAM the star it orbits would produce.
Its like trying to hear what someone is saying when they are stood next to the speakers at a rock concert and you are on the other side of the stadium.
You would be better getting a video camera with a telephoto lens and trying to lipread :)
liqbase
well, I was using particle ambiguously as in pretty much anything, not specifically as a piece of dust, or something somewhat "large", but anything that isn't a vacuum (atoms, molecules, etc)
Black Hole Strikes Deepest Note
Astronomers have detected the deepest note ever generated in the cosmos, a B-flat flying through space like a ripple on an invisible pond. No human will actually hear the note, because it is 57 octaves below the keys in the middle of a piano.
Sound travels, there just isn't enough pressure for our ears to hear it at any distance, I would imagine that even screaming right next to eachother would probably only make it a few feet before becoming inaudible and dropping down like the "57 octaves below..." I doubt that the sound actually started that low, but who knows...
"quantum effects would completely destroy any signal contained years before one particle could collide into the next"
/pedant
I think you mean "obscure the signal", to "destroy" it would imply you can destroy information.
And did you exchange a walk on part in the war for a lead role in a cage? - Pink Floyd.
I would imagine that even screaming right next to eachother would probably only make it a few feet before becoming inaudible and dropping down like the "57 octaves below..." I doubt that the sound actually started that low, but who knows...
an octave is a measurement of a signal's frequency, not amplitude. space would not change the pitch of your words, it would render them completely silent.
-I only code in BASIC.-
Red shift. Most astronomical stuff is moving away from us, owing to universal expansion.
No, that's gravity. I don't know about you, but I can't hear gravity. The only way I can hear vibrations is if there is an atmosphere for the vibrations to act upon.
"Give a man fire, and he'll be warm for a day; set a man on fire, and he'll be warm for the rest of his life
So let's see. Middle C is about 260 Hz (with Bb slightly lower). 57 octaves lower is 2^-57 * 260 Hz, which is 5.5 x 10^14 seconds per cycle, or about 17.4 million years per cycle. Yeah, I think it's fair to say that humans aren't going to hear this signal.
...following the principles of Heisenburger's Uncertain Cat...
Sound is the propagation of a wave within a medium, and in space, there is no medium with the density required to propagate a wave of any kind.
The sentence above is the initial, much geekier version of the tagline, which was later reduced to "In space, no one can hear you scream"
-- the only thing we have to fear is really scary things
to "destroy" it would imply you can destroy information. /pedant
And that's problematic how? There's no law of conservation of information. Information is destroyed all around us all the time. Look up "second law of thermodynamics" one of these days.
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