Re: Sonic boom, Light Boom?

In article <[EMAIL PROTECTED]>,
Paul F. Dietz <[EMAIL PROTECTED]> wrote:
>> Considering that there are a few atoms per cubic _meters_, it might be
>> detectable with appropriate instruments, but would certainly not be
>> visible...
>
>The density of the ISM is on the rough order of an atom per cubic centimeter.

No, that's an old number.  The "Local Cloud" in which we sit is about
0.07 atom/cc, and the "Local Bubble" outside that (several hundred LY 
across) is down around 0.005 atom/cc.
-- 
MOST launched 30 June; first light, 29 July; 5arcsec    | Henry Spencer
pointing, 10 Sept; first science, early Oct; all well.  | [EMAIL PROTECTED]