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Little Bo Peep
05-28-2004, 04:17 PM
This questoin is in reference to something I read a few months ago in some astronomy mag. I might have this totally wrong, so bear with me, but this has kind of been boggling my mind ever since. Here goes:

Apparently they (i.e.: scientists & astronomers) were studying this star that was going supernova, and at some point during the whole star-gone-supernova process, they said that they had recorded a C Minor (the musical note). So they were saying that a star that reaches a certain stage of going supernova emits a C Minor, and that this note was the lowest note ever recorded.

I've always been taught that sound is impossible in space. What's the deal? How can they record a C Minor emitted from a supernoova then, if sound does not travel in space? Is sound still produced in space, but does not travel? Does it travel in space by some complex mechanism that was too complicated to teach us in the first place?

:confused: LBP

rkts
05-28-2004, 04:27 PM
I don't know, but I do know that C minor isn't a note.

And I doubt it was the "lowest note ever recorded." If you want a low note, wave your hands back and forth. If you do it once per second, you make a vibration of 1 Hz. Once every other second, you make a vibration of 0.5 Hz. Once every 100 seconds, 0.01 Hz. Etc.

rkts
05-28-2004, 04:47 PM
Actually, all nitpicking aside, I have heard about this, so I did a search and came up with this (http://www.space.com/scienceastronomy/blackhole_note_030909.html). They say it is 57 octaves below B-flat below middle C, which means its frequency is 220 [A below middle C] * 2^(1/12) [up one half step] / 2^57 [down 57 octaves] = 1.617e-15 Hz. Which means one vibration every 6.183e14 seconds, or 19,592,835 years.

So yeah, that is pretty low.

rkts
05-28-2004, 04:56 PM
And finally, to actually answer your question, there is this sentence in the article:A special image-processing technique was used to bring out subtle changes in brightness that revealed the presence of ripples -- the sound waves.Which seems to me to be saying (though I may be wrong; it is a bit ambiguous) that the waves did not actually reach the earth, but that they were merely seen through the effects they had on the matter being observed.

Little Bo Peep
05-28-2004, 04:57 PM
I don't know, but I do know that C minor isn't a note.

What do you mean C Minor isn't a note? What about all those classical music pieces "Symphony such-and-such in C Minor" (eg. Dvorak's Slavonic Dance Opus 46, No. 7 in C Minor)? C is a note. C Minor is like C flat and C Major is like C sharp isn't it? I mean, I'm no Mozart, but still...

My question isn't about harmonics or a debate about whether C Minor is or isn't a note. It's about sound travel, or lack thereof, in space.

MikeS
05-28-2004, 04:57 PM
To answer the question you're confused about, they didn't actually record the sound; rather, they looked at the gas surrounding the black hole and discovered that its density varied just like the Earth-bound sound waves you know and love, only several octaves deeper. You're right in saying that since there's no medium for the sound to travel in, we shouldn't be able to hear it; but in this case, it was actually possible to see it.

On preview, rkts said pretty much the same thing.

Little Bo Peep
05-28-2004, 05:04 PM
You're right in saying that since there's no medium for the sound to travel in, we shouldn't be able to hear it; but in this case, it was actually possible to see it.

Ah, I see. So by "seeing" the sound, they could deduce its frequency and hence make the comparason to sounds we know, like to qualify it for us lay people? Am I getting this right?

Loopus
05-28-2004, 05:08 PM
What do you mean C Minor isn't a note? What about all those classical music pieces "Symphony such-and-such in C Minor" (eg. Dvorak's Slavonic Dance Opus 46, No. 7 in C Minor)? C is a note. C Minor is like C flat and C Major is like C sharp isn't it? I mean, I'm no Mozart, but still...

C minor is a key. C natural, flat, and sharp are notes.

Little Bo Peep
05-28-2004, 05:11 PM
C minor is a key. C natural, flat, and sharp are notes.

Well there you go! Guess I was wrong...

Thanks!