what is "frequency" of human voice

techno di said:

on the other hand , massive universal explosions and hugr-mass bodies Collision take place in the universe and we dont hear them !

No one in space can hear you scream.

Frequency of Human Voice..................In the case of my ex-wife, it was very frequent.

Sound is a mechanical wave, similar to what happens when you throw a rock in a pond, but with air and in three dimensions.

In the case of human voice, this mechanical wave travelling around ain't continuous, it is composed by waves at a certain frequency. And for a good reason. The organ emitting that sound (vocal cords) does so by vibrating, which is a wave-like movement that results in a wave-like mechanical wave as it pushes air back and forth at a certain frequency. Like the strings of a guitar, they oscillate pulling air back and forth.

All devices with moving parts (and some even without moving parts) do vibrate one way or another when in operation, and it's their vibration that generates the sound even if they don't have vocal cords or something equivalent. Air/water movement also can and does cause vibration when hitting materials, and that can become sound (this is how the vocal cords work, and how a trumpet works).

Human ear is a pressure sensor, and for each time it is depressed by such a wave it sends a signal to the brain, that has the exhilarating job of keeping time and thus determining the frequency of the sound. It also has quite a few different kinds of sensor cells, and each one has a intensity threshold. They will send a signal to the brain only if kicked hard enough by the wave. The more intense the sound is, the more sensor cells send their signal, so the brain can figure out the sound's intensity as well.
There are lower and higher limits in frequency and intensity because of biological limits of the brain areas, most animals have far better hearing without having huge parts of the brain dedicated to sound perception, and sensor cells are more or less the same across the board.

The intensity is just how much energy each wave carries, which is a factor of how big/powerful the emitter is and the distance between emitter and sensor.
A bomb exploding is an example of powerful more or less single sound wave, so powerful that turns air into the ultimate sledgehammer. Firecrackers work the same, but at a far smaller scale.
Intensity decreases with distance, as a mechanical wave travels by transferring kinetic energy between air molecules, and this isn't anywhere near 100% efficient. The energy loss heats up the air.

As you may have noticed by now, a mechanical wave (as sound) is actually a fancy term for "matter nudging other matter", not something autonomous like electromagnetic radiations and photons. So if there is no such matter to nudge, there is no mechanical wave.

Outside of Earth's atmosphere there is what is called "vacuum" that is practically empty space (there is some tiny bit of stuff but is so rare and spread out that it won't interact at all), so no matter to nudge, so no sound. (also nothing to breathe, but you probably knew this already)

You could be sitting next to a planetary collision (yeah, a head-on collision between planets) and you wouldn't hear nothing, as there is nothing to be nudged from the planets to your ears in the vacuum of space.

DISCLAIMER: the above is educational, meant to explain the general concept. How everything works exactly is far more involved.

techno di said:

on the other hand , massive universal explosions and hugr-mass bodies Collision take place in the universe and we dont hear them !

techno di said:

on the other hand , massive universal explosions and hugr-mass bodies Collision take place in the universe and we dont hear them !

Is that the same principle as when there is a car crash on the other side of town, I don't hear it?

bigmck said:

techno di said:

on the other hand , massive universal explosions and hugr-mass bodies Collision take place in the universe and we dont hear them !

Is that the same principle as when there is a car crash on the other side of town, I don't hear it?

Not exactly, although the result is more or less the same.

Anything in an atmosphere (like a car crash) generates sound that loses intensity with distance until you cannot hear it anymore.
Whatever happens out of an atmosphere (even supernova explosions that blow away gas giants in a couple seconds when the shockwave arrives) does not generate any noise at any distance.
While if you stay too close you could still get the shockwave and pretty damn fast shrapnels, that "close" is very very close if compared to the murderously huge range that the sound generated by something of that scale would theoretically have if space wasn't a vacuum.

Sound waves cannot occur in a vacuum. Hence the comment from the movie Alien "In space no one can hear you scream".