Chris L Peterson wrote:

Noise is noise- by definition devoid of informational content. When you can put


That's not completely correct. The very property of noise is a flat spectrum
when averaged over a wide range of wavelengths. But noise carries energy and
therefore signal - in its amplitude.
The point I try to make is that generically, the noise level you observe
(i.e. the "background"), will remain constant (if you manage to eliminate
all noise generators from your detection equipment, it'll come down to
either quantum noise or the 3K radiation), but a change in amplitude (not
in the freqency distribution) is indicative of an "event". Things like
solar flares or supernova explosions in our galaxy, for example, would
raise the "noise level" even on detectors not directly pointed at the source
of that phenomenon.
Not that this carries signals which a TV receiver would decode into a
human-recognizable image. But monitoring noise levels is a true scientific
method that's, e.g. been successful at detecting neutrinos from the SN1987A
in the kamoikande neutrino detector. Or that's being employed at the south
pole Amanda neutrino detector to "fingerprint" supernova explosions. Also,
a lot of solar radio observation is nothing but "listening at noise", i.e.
signal intensity within wide bands of radio emission. Many of those solar
activity reports are nothing but that - reading of a "noise level" in a
certain radio band.

To some it's just noise. To others, it's music


Bye,
FrankH.