And *this* is a follow-up "finding buried things and isotopic traces"
that was a follow-up to the threads in early Feb08 about the History
Channel's "Life After People" special.
So, you're an expanding interstellar civilization. Given the Fermi
Paradox, you don't expect to find any active technic civilizations in
your neck of the galaxy, in this era. You *might* find some remnants
that are ten or a 100 million years old. The ones built by posthuman-
and K2-level (star-tapping) tech should probably be more obvious. What
should your archeologists look for?
As I recall, early speculation about alien-built Dyson spheres
amounted to "look for anomalous IR sources where stars should be." If
the place has been converted to computronium (a la Stross's
_Accelerando_) which then died, that should be rather obviously not
natural. (And at 300+ detected extrasolar planetary systems, we're
getting an increasingly good idea of what "natural" looks like.)
Maybe the locals twiddled with their star, lofting mass off the
photosphere, and it no longer shows a typical profile. That might be
visible remotely, as in Vinge's _A Deepness in the Sky_, where the
cyclic behavior of the so-called On/Off Star is inexplicable by normal
stellar models (and by the end of the story the characters still have
only speculation).
Have any stars been moved into unusual positions by long-term gravity
tractors? (The "stellar signpost" has been used as a throwaway idea
at least once -- there was a mid-'80s _Analog_ story about
civilizations all trying incompatible methods of signalling. And it
was by somebody recently, maybe in one of the _New York Times_ blogs.)
There's a bit in Robert F. Sawyer's _Calculating God_ in which the
_Merelcas_ xenopaleontological expedition finds a world with a
city-sized obsidian slab covered with spiky points. They speculate
that the locals had gone upload (Greg Egan _Diaspora_-style), and
hidden themselves beneath this armor.
In Vinge's _Marooned in Realtime_, bobbles were put in cometary orbits
for long-term storage (probably because they spend less time in the
vicinity of Jupiter to be perturbed). This should work even without
bobbles, but that's a lot of volume to check (especially if they're
out of the ecliptic).
What's the half-life of things orbiting *way* above atmospheric drag,
e.g. GEO? (Exact parameters will vary with an alien world.)
In _The Mote in God's Eye_, all the asteroids have been neatly moved
to safe orbits, and the Orion-type deflection-craters, which should
have remnant radioisotopes, are cold. (The expedition planetologists
don't initially interpret this as evidence of intelligent action.)
They've also been stripped of all metals, and many of them have been
carefully excavated into living spaces with eggshell-thin walls.
Other ideas?
--
** Phillip Thorne ** pethorne@[EMAIL PROTECTED]
**************
* RPI CompSci 1998 *
** underbase.livejournal.com ***************************
|
