the reason for my question is that I seams to remember someone telling me (12-13 years ago) about a scientific theory that claimed that sounds never disappeared, that all sounds in some way was somewhere in the atmosphere? (I think that this person had read about this theory in a popular scientific magazine)
This persons claimed that this theory (with the use of the right tool) could make it possible for us to actually hear what Jesus and other historical persons have said through history.
Does anyone know or have heard about such theory ?
I understand the theory – it’s basically the same idea as: “people on Alpha Centuri are watching our TV programs from 1950.”
My primitive knowledge of sound and audio suggests that it won’t work. Every sound is based on a single event (whether the eruption of a volcano or a baby saying “mama.”) Over time and distance, the force that produced the sound will attenuate. Over enough time and enough distance, it will become “unamplifiable.”
Thankfully, the the earth and its atmosphere are damped. If that were not so, we’d all be deafened by the noise of every meteor collision, volcano and hurricane of the last 4 billion years. Heck, there might have been enough sound energy produced over that period to melt the Earth’s crust.
You probably overheard someone talking about Archaeoacoustics, where for example, a potter’s wheel impresses its noise on the structure of spun pots. As far as I know, no one, besides possibly Leo G. Carroll, has ever gotten a convincing result looking for sounds in old objects.
Perhaps your friend was thinking of the tenet of quantum physics that information cannot be destroyed. This tenet formed the basis of a famous bet between Stephen Hawking and John Preskill over whether information could be lost in a black hole.
Heck, the idea of capturing long-past audio was the premise of a series of 1941 episodes of the Superman radio show (“Doctor Roebling and the Voice Machine”). A test run of the machine casually plays back the Gettysburg Address.
I think I read about it in Pop.Sci. once upon a time. A movie “A Conneticut Yankee In King Arthur’s Court” starring Will Rodgers used it.
All pure BS, “cut from the whole cloth.”
Vibration theory will show that sounds damp to zero in a very short time regarless of frequency or volume.
Even without damping, consider how many trillions of words have been spoken in the last 2,000 years. Even if (in isolation) one word were still loud enough to be identifiable, how would you hear it against such a background?
Suppose you were in a the middle of a circle of people – say 1,000 people, each 500 metres from you, all shouting different things at you. If there were just one person, you might be able to hear them, but isolating one voice in 1,000 would be impossible.
What is a sound? A series of vibrations of molecules…usually in the air. So when I speak a create pressure waves, regions of densified and rarefied air. And when these waves hit your eardrum they cause it to vibrate, which stimulates tiny little hair cells in your cochlea, which send signals to your brain.
So if every molecule in the air were completely still, that wave could bounce around forever. Sound waves CAN bounce around, this is what causes echoes. Except, every molecule everywhere is vibrating already. Air is moving around. Eventually the random motion of the molecules overwhelms any signal. And two signals can interact and wipe each other out. So not long after a sound is created, it simply makes the air randomly vibrate a tiny bit more than it used to…that is, the air gets hotter.
Toss a rock into a still tank of water. Ripples spread out, bounce around, create chaotic patterns, then eventually die. The tank becomes “still” again, meaning that the only movement is brownian motion of the water molecules.
HA! I’ve heard the exact “theory” the OP describes. I can’t say either way if it’s true or not, though it does sound like rubbish. You’d have to ask, “How could that possibly work?” My general take on it is that it’s just one of those fun, interesting things for stoned first year philosophy students to discuss.