Re: Return to No Stealth in Space

Wasn't it  who 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.

Not with today's technology, but something like the proposed NASA TPF-C 
technology might have had a good chance. TPF-C would have used a visible 
light coronagraph to reduce the light from the target star by a factor 
of about a billion.

The technology of the TPF-I proposal, and that of ESA's proposed Darwin 
mission probably wouldn't work. That technology uses infra-red nulling 
interferometry to reduce the light from the target star by a factor of a 
million. That's enough for spotting planets because they peak in the 
intra-red.

-- 
Mike Williams
Gentleman of Leisure