Re: Return to No Stealth in Space

In article
<c5edc0c1-efe7-47ca-9abd-4008643381b9@[EMAIL PROTECTED]
>,
 <sigidunum@[EMAIL PROTECTED]
> wrote:
>On Mar 18, 7:01 pm, jdnic...@[EMAIL PROTECTED]
 (James Nicoll) wrote:
>
>> might have a peak power output of 5^16 Watts (plus whatever
>> for ineffeciencies).
>>
>>         Could we spot this at 4.3 LY? Would we recognize it
>> for what it was?
>
>Cheap dumb answer: the power output of the Sun is 4 x 10^26 watts.
>So, this is about 10^-10 as bright as the Sun.
>
>One way to phrase the question: can we detect a one-ten billionth
>change in luminosity?
>
>As for absolute magnitude, Alpha Centauri is about as bright as the
>Sun (it's a bit brighter actually, but this is BOTE).  Its visual
>magnitude is just about 0.0.  So, your Centuarian torch****p would have
>an absolute magnitude of about +25.
>
>I'm thinking no, we wouldn't see it.

	OK, this probably has a flaw in it somewhere: The shuttle
jet is what, 3000K? And ISP scales as the square root of temperature,
so if the ISP in this case is 500,000 or about 1000 times greater
than the shuttle's ISP, then the temperature should be somewhere 
around 3 billion degrees.

	If I run that through Wein's law, I get a peak at about
10^-12 m. That's gamma radiation, right? 
-- 
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