[extropy-chat] ASTRO: Spitzer/SIRTF images released

[Robert J. Bradbury]

[Not sure if I sent this before -- if its a duplicate byegones.]

On Fri, 19 Dec 2003, Harvey Newstrom wrote:

> [snip]  SIRTF can see objects as small as "super-planets", which
> they define as bigger than 100 Jupiters.
>
> So it seems that it would be impossible for SIRTF to see a Jupiter brain.

Yes, Harvey, in a classical sense you are correct.  But I believe the
best description we have for a Jupiter Brain now is the one that Anders
provided and I don't think it discusses power sources or heat signatures.

While I would tend to agree that at near-IR wavelengths a Jupiter Brain
around a star that uses normal solar power would probably not be
detectable -- a free floating Jupiter Brain using internally power
from fusion reactors could be detected.  (I discuss this briefly
as internally powered Matrioshka Brains in some of my papers -- but
the same ideas would apply to Jupiter Brains.)

That is what caused me to point out the asteroids.  And though the
asteroids cited are known, detecting dark asteroids such as carbonaceous
chondrites at visible wavelengths can be quite difficult and is much
easier for a telescope like SIRTF.  And in most cases, whether for
the absorption of visible solar energy or for the radiation of waste
heat energy, the best materials involved are very dark and therefore
difficult to detect at visible wavelengths.

Robert