Harvey Gerst laid this on me:

(Michael Dines) wrote:
Charles Thomas
wrote:

I'm confused.
How "low" can you really get? I mean... 1 hz is just a pulse
every second. It's not really a "tone".
Isn't everything below about 20 hz just a bunch of pulses in
decreasing frequency? It's not going to be heard as a "note" of
any kind is it?

And, since black holes aren't in an atmosphere there's no audio
waves. And because of their gravity light waves can't escape - so
how do they propagate this hum?

It's precisely because light waves can't escape, black holes are
forced to hum; without light, they can't see the lyrics.

Harvey Gerst
Indian Trail Recording Studio
http://www.ITRstudio.com/

The scientific information available on this noosgroop is
overwhelming at times.

Sean