Thoyd Loki

A really dumb question, I think

30 posts in this topic

I understand that there is no sound in space. Is this an absolute? Meaning, are there not forces with enough magnitude that they would have to be heard assuming someone or something was there to hear it?

If I put my ear up next to the sun, is it actually making no sound right there two feet away from me?

Apologies if this is a little elementary, but the question won't leave me alone!

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I don't know much about space, but I know a little about sound. Sound, in a human, is caused by fluctuations in the pressure acting upon the ears. In space, what pressure is acting upon the ears?

From what I understand, however, radio waves are able to travel though space. Is this how the astronauts are able to communicate with mission control?

This would seem to imply, to me, that some kind of fluctuations or vibrations or quantums (?) of matter capable of inflicting varying pressures upon contact with some kind of substance or environment are able to travel through space. But my intuition in matters of physics have been refuted and corrected on this forum before (to my gratitude).

I don't know if the sun makes an audible sound or not, but my guess would be that if it does, you wouldn't have to put your ear next to it in order to hear it-- since there is nothing in space to hinder motion, I would assume the sun would be just as loud ten trillion miles away, as long as there's nothing between you and it (like an atmosphere).

But my last confusion about your post is that you say "no sound in space," and then you say "assuming someone or something was there to hear it." Are you asking if sound can travel through space, to an observer (who may not be "in space"), or if it's possible for an observer to exist in space, hearing a sound?

What do you mean exactly by "in space?" Is Earth and its contents in space? A astronaut in a space ship? In a space suit outside of his ship? I apologize if there is a meaning of "in space" that is common knowledge or a specific physics term I'm not aware of; at any rate, I'm not sure what you meant by it.

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But my intuition in matters of physics have been refuted and corrected on this forum before (to my gratitude).

I don't know [...] but my guess would be that ...

What do you mean by "intuition"?

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I would assume the sun would be just as loud ten trillion miles away, as long as there's nothing between you and it (like an atmosphere).

An atmosphere is what would make sound possible. Space is a vacuum; it contains no matter. Sound waves need matter to exist; the occur when one molecule hits another which hits another which hits another, etc. When that collision-chain reaches the ear, you hear a sound.

As I understand it, sound actually travels more quickly in situations where molecules are more tightly bound together, such as through solids. There are other factors which cause the sound to decrease in volume however, which is why we have problems hearing through walls.

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To elaborate:

I'm sure the sun does, in fact, make a sound, but as soon as the sound wave reaches the vacuum, it stops travelling.

I'll wait for you to go check it out for me. Take water. I heard its hot up there.

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I understand that there is no sound in space. Is this an absolute? Meaning, are there not forces with enough magnitude that they would have to be heard assuming someone or something was there to hear it?

In physics, by "sound" we usually mean a mechanical wave, a disturbance that propagates through a medium. The medium can be a liquid, or a solid, or a gas like our common atmosphere. Sometimes we use "sound" to refer to that portion of a mechanical wave possessing a frequency that is a audible to the human ear. There exists a great range of frequencies above (ultrasonic) and below (infrasonic) that which is audible to us, much like the electromagnetic spectrum where there are frequencies above (X-rays) and below (microwaves) that of visible light.

In interplanetary space there is a sparse but gaseous medium which qualifies as sound in the sense of propagating a disturbance through a medium. However, the frequencies of these disturbances are far from the range of that which is audible to us. Even in intergalactic space, which is generally much less dense than interplanetary space, there still exists enough of what we might describe as a medium as to propagate a disturbance. However, to do so requires a tremendous amount of energy, energy associated with exotic cosmological objects and unusual events. But, even so, these disturbances are far, far outside of our perceptual hearing.

If I put my ear up next to the sun, is it actually making no sound right there two feet away from me?

Indeed, there is sound due to solar activity, right at the surface of the Sun and propagating many billions of miles further. But, again, these are sounds that can be detected with specialized instruments, not within our audible range.

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But my last confusion about your post is that you say "no sound in space," and then you say "assuming someone or something was there to hear it."  Are you asking if sound can travel through space, to an observer (who may not be "in space"), or if it's possible for an observer to exist in space, hearing a sound?

What do you mean exactly by "in space?"  Is Earth and its contents in space?  A astronaut in a space ship?  In a space suit outside of his ship?  I apologize if there is a meaning of "in space" that is common knowledge or a specific physics term I'm not aware of; at any rate, I'm not sure what you meant by it.

No, the observer must be in space, floating out there in the "vacuum". Or the receiver, like a microphone, out there in space. And of course we cannot be in space with our ears exposed, so I am speaking in hypotheticals.

I'm not sure if there is a physics meaning to "in space" as I am almost entirely devoid of knowledge in that field. So, I mean space as any other layman means it.

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Thank you, Mr Speicher for the answer. I was thinking, dimly, along these lines as I know that space isn't a total void.

This question actually came up in a discussion I had with someone who was criticising science fiction movies for the fact that ships produce sound in the movies and that this is impossible. It certainly is, but it is also entirely irrelevant as I think it would make such movies dull. But, considering the gigantic occurrences in the universe (spaceships not being one of them), I found it hard to believe they would produce no sound at all.

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A somewhat related issue:

I used to collect meteorites, and did a little reading about them. Several years ago I read something interesting (can't recall exactly where; I do recall that it did not look like just idle speculation).

It is somewhat common for ground-based observers to report that they hear a sound, when they spot a meteor. Yet the meteors they are seeing are at such a high altitude, that it would take quite a few seconds for a sound (if there were any) to reach the observer.

As I recall, there is some evidence that what they are hearing is real. The meteors emit radio waves (travelling at the speed of light) that, under certain conditions, can be converted to audible sound when passing through a person's hair.

(Here's hoping someone more knowledgable than I doesn't paraphrase Rostand on me: "Your mind may be as curly as your hair.") :)

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A somewhat related issue:

I used to collect meteorites, and did a little reading about them.  Several years ago I read something interesting (can't recall exactly where; I do recall that it did not look like just idle speculation).

It is somewhat common for ground-based observers to report that they hear a sound, when they spot a meteor.  Yet the meteors they are seeing are at such a high altitude, that it would take quite a few seconds for a sound (if there were any) to reach the observer.

As I recall, there is some evidence that what they are hearing is real.  The meteors emit radio waves (travelling at the speed of light) that, under certain conditions, can be converted to audible sound when passing through a person's hair.

(Here's hoping someone more knowledgable than I doesn't paraphrase Rostand on me: "Your mind may be as curly as your hair.")  :)

Although not quite common, there is nothing silly about Bill's report. Although reported throughout antiquity, the most famous in modern times was almost 300 years ago, wherein the great astronomer Edmund Halley (Halley's comet) reported on observations of an "Extraordinary METEOR" that was a "very great Height thereof above the Earth" and for which certain "Explosions" were heard with great "Surprize and Astonishment." Halley tried to explain the observations but, as he wrote, "I must confess that I know not." (An Account of the Extraordinary METEOR Seen All over England, on the 19th of March 1718/9 With a Demonstration of the Uncommon Height Thereof. By Edm. Halley, LL. D. and Secretary to the Royal Society, Philosophical Transactions (1683-1775), Vol. 30, pp. 992-994, 1717.

It is only in the past decade that serious attempts to understand the phenomena have been made. There have been maybe a dozen or so papers during that time, the most reasonable hypothesis being the electrophonic burster model. These generate very short popping or clicking sounds, similar to those reported by serious observers. There is a fairly restrictive set of criteria that the meteor must meet in order to generate these elctrophonic burster sounds. The Leonid meteors that return each year have been favored in the studies. A certain minimum mass is required to generate a shock wave which in turn generates a very low frequency (VLF) signal which through l;ocal transduction is converted to sound nearby a ground observer.

A strange, but apparently real phenomena that is just now really being understood. No worry by Bill for any paraphrase of Rostand. :)

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Golly! Thanks for the erudition!

I just did a Google search (meteor + sound + hair) and found quite a few references, including:

"In laboratory tests, Keay finds that suitable transducers are surprisingly common. Simple materials like aluminum foil, thin wires, pine needles -- even dry or frizzy hair -- can intercept and respond to a VLF field."

from: http://science.nasa.gov/headlines/y2001/ast26nov_1.htm

and

"The very-low-frequency radiation, traveling at the speed of light, can be so intense that it can make objects on the ground -- anything from eyeglasses to dental fillings, both of which Hammer has -- quiver and vibrate.

The key is what sort of objects -- even hair or pine needles will suffice -- lie in the observers immediate surroundings."

from: http://www.space.com/scienceastronomy/sola...und_000706.html

The few meteors I've seen have flashed by with such startling rapidity, appearing so unexpectedly and briefly, that they almost seemed figments of my imagination. Yet one time I did seem to hear a whooshing sound, that was gone in an instant.

(If you had a Smilie with its hair standing on end, I'd insert it, here!)

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The few meteors I've seen have flashed by with such startling rapidity, appearing so unexpectedly and briefly, that they almost seemed figments of my imagination.  Yet one time I did seem to hear a whooshing sound, that was gone in an instant.

Consider yourself lucky. I have spent a lot of hours viewing the night sky (I had a beautiful computer-controlled LX200) and I have seen many meteors, but nary a pop, a crackle, or a whoosh. It really is an interesting phenomenon that has been virtually dismissed since Halley almost 300 hundred years ago, but this past decade has seen some very nice ideas and investigations that treat this "electrophonic" sound seriously.

For several years we made a family thing out of the Leonids, staying up into the morning to watch them. But there are other lesser-known meteor events that occur throughout the year. The predictions for these events has been improving over the years, and there have been some decent estimates of the meteor rates and time. But reading the historical records makes the events that most of us have seen today, pale by comparison. Meteor events that virtually turned night into day.

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I have observed a really interesting meteor shower when I was younger and I could have sworn I remembered at least one that made a "whoooooosh".

But the one(s) that made this noise appeared much larger in the sky than the others. Whereas other shooting stars were just a dot of light that zip past I thought I remembered the aforementioned one(s) appearing as a distinctly round bright object with some kind of trail behind it that looked almost like an exhaust-line left by a jet. Perhaps we saw a few diamonds in the rough with meteors or maybe I have a poor memory since this was nearly 10 years ago.

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For several years we made a family thing out of the Leonids ...

... I remembered the aforementioned one(s) appearing as a distinctly round bright object with some kind of trail behind it that looked almost like an exhaust-line left by a jet.

I had a wonderful front row seat for the 1998 Leonid meteor shower. I was in the northern Virginia horse country at the time, and for that year the best observations -- or so I read -- were on the east coast. There were three types: dim reddish ones, white ones that flashed and disappeared after a few seconds, and a very few that had visible trails and even broke into separate meteors (Or so I heard, since I never saw one of those myself :D ). The brighter ones that popped, if they did so behind me would light up the treeline in front of me! I'd look at where the "poppers" were through binoculars for several minutes afterwards watching their vapor trails twisted and dissipated by the upper atmosphere. An awesome show, especially considering that most of these meteors are about the size of a grain of sand! But they are hitting the upper atmosphere at 71 kilometers per second.

The best meteor I ever saw was last month and was a consolation prize for the fact that NASA's Deep Impact was a bust as far as ground observation was concerned. I was up at Mt. Pinos north of LA in the hope of seeing the impact, but nobody up there -- even folks looking through 25-inch Dobsonians -- saw anything. We had to settle for listening to the cheers from JPL's Mission Control while on commercial break from that stargazer's AM radio staple: The Art Bell Show. :D

It left a clear trail and got brighter and dimmer at least twice. At its brightest, it was at least as bright as the full moon although it subtended less of the sky. Picture a car headlight about 100 or so yards away or a street light -- that's what it looked like. Everybody I was with up on the mountain that was still awake was saw its light regardless of where they were looking at the time. And I was looking at it long enough to wonder if it would hit Bakersfield. :D

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I had a wonderful front row seat for the 1998 Leonid meteor shower....

Thanks for all the very nice reminiscing. Your mention of Mt. Pinos in particular brought back a lot of fine memories of my own.

For those who do not know of Mt. Pinos, it is a beautiful dark-sky observing site in Southern California. Many weekends during the year will see 100 or more dedicated star-gazers setting up their equipment in a flat paved area that is at about 8118ft. elevation. Trees surrounding the area cut the wind, keeping telescopes steady, yet the sky above is open to viewing. Those who have never been to a dark-sky site before always ask "What's that?" while pointing to the Milky Way. Most people never see how beautiful the Milky Way is to the naked eye once you get far-enough away from the city glow.

And what a friendly group of people assemble at Mt. Pinos. Astronomy teachers bring their students to the area and many of the resident observers allow the students and others to peek through their telescopes, explaining about the planet, star, nebula, etc. that is being viewed. There is nothing quite like having a group of good-natured people sharing an interest and common values. Mt. Pinos is a wonderful place to exercise the wonderful hobby of amateur astronomy.

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Mt. Pinos sounds like a beautiful place. Down in the humid flatlands of Indiana it's difficult to have a night with good seeing conditions. A couple of years ago I was eager to see the Leonids because of reports that it could be a once in a lifetime meteor shower. Unfortunately there was impossibly thick cloud cover here. I was determined not to miss it and drove a few hours due west into Illinois in hopes that there'd be at least some open sky (clouds moving west to east). Fortunately that was the case and there was still time to watch for meteors. While it wasn't a storm, I saw a number of incredible meteors, including a few that were a dazzling bright blue-green. (Because of the the chemical composition of the meteors I suppose?)

The most incredible night sky I ever saw was during a trip to New Zealand. I stayed overnight at a tiny place (no more than a hotel really) called Fox Glacier, by the glacier nearby of the same name, and went out for a walk late in the evening. It didn't take long to get away from the outdoor lights. As my eyes adjusted I was stunned at the brightness of the night sky. I noticed that the landscape was lit as though by a bright moon, but there was no moon - the sky was so clear that the starlight was bright enough to cast perceptible shadows of me on the ground, something I'd never seen before nor since (that I recall.) Then looking at the sky was like looking from an alien world, because it was a very unfamiliar southern hemisphere perspective. What I initially thought were earthly clouds suddenly struck me as what they were really were - the Magellenic clouds, small galaxies orbiting our own (as I understand it.) I spent a long time taking in that sky before going back. I've thought a number of times that going back there with a telescope just to observe would probably be worth the trip by itself.

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Several years I got up in the middle of the night to watch the Leonids, and one year they were very good. (At least I thought they were good - for a while they were arriving in my field of view at the rate of about once every one or two minutes.) But I never heard anything. But now that I know that meteors sometimes can be heard, I'll listen more carefully.

(Seeing meteors in November where I live, in the often rainy and cloudy lowlands of Western Washington - with big trees everywhere - is often not possible, so when there's enough clear sky to see them, it's a real treat.)

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For all the sky gazers and those interested, the Perseids are coming into view around the 12th of August. I've been trying to find the best viewing time and have found a couple of different quoted times, but 11pm - sunrise on the 11th and 12th of August seem to be the quoted the most. In Discover Magazine I read that the 15th is the best time. I just wanted to give a heads up for those who would be interested and were unaware.

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For Bill and Stephen: Given whats being said here about VLF signals, doesn't that give them some kind of a potential as a weapon? Have there been military programs aimed at creating and harnessing them in a manageable way?

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Given whats being said here about VLF signals, doesn't that give them some kind of a potential as a weapon? Have there been military programs aimed at creating and harnessing them in a manageable way?

All sorts of electromagnetic weapons for military use have been considered for some time, most seriously since the 1970s. VLF was probably in use earlier in Iraq.

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VLF was probably in use earlier in Iraq.

By us, I assume. And in what way?

I just have this image from a scene in Real Genius:

"You. You in the turban. This is Allah! You've been touching yourself. Stop touching yourself !!!"

Sorry, couldn't resist that one. It was a moral imperative ... :D

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By us, I assume. And in what way?

Low-end fequencies can cause disorientation and nausea, and high-end frequencies can cause serious damage. I do not know this as a fact about Iraq, but I have been told by more than one person "in the know" that the disruptive low-end of VLF was effectively used more than once. That which I do know factually I cannot really talk about, but, as I said, starting in the 1970s serious research in this area was done. Note that electromagnetic radiation is a natural consequence of most nuclear weapons, as was slowly learned in the 1960s testing, so learning how to effectively generate intense burst pulses offers a potentially powerful weapon.

I just have this image from a scene in Real Genius

I love that movie. They did a lot of the filming for that at Caltech.

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As for the low-end frequency weapons, I recall watching a program, possibly on the Discovery channel or The Learning Channel, a few years ago about developmental police weaponry. One of the discussed weapons was a "low-frequency cannon" that police could use to disable criminals (the example used in the show was of a criminal taking hostages in a building) by some kind of crippling nausea; this would completely almost completely disable the criminal without having any long-term negative effects on the hostages.

Like I wrote, that was a few years ago, and I don't know if anything ever became of it, but it sounds like something similar to what Stephen was talking about.

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Wow, VLF as a weapon is both very creepy and amazing. Reminds me of The Xylophone in Atlas Shrugged.

Makes me think of a weapon that could determine the resonant frequency of it's target then shoot a laser of high-amplitude sound waves at it to resonate it to shreds.

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