Subject: (whorl) vampires make bootstrap lift off

From: Michael Andre-Driussi <mantis at sirius.com>
Date: Tue, 05 Sep 2000 12:48:45 +0000

wombat wrote:
>We know the inhumi can fly on Blue. If the inhumi can spread themselves
>thin enough to drift down in the atmosphere of Blue, then they don't need
>heat shielding. Our space vehicles need serious heat shielding because on
>re-entry they are basically falling through atmosphere, not flying or
>gliding.
>
>One engineer I know described the Space Shuttle's reentry as being "as
>graceful as a falling brick". Compare this to the flight of a low-orbit
>airplane like the U-2--the U-2 didn't have much in the way of heat
>shielding, because its descent was controlled flight.
>
>I agree that the problem of launch from Green is by far the more puzzling,
>unless the inhumi can somehow teleport (because of residual Neighbor blood
>making distance less certain?).

Yay, we are on the same thought here: I was meaning to mention the limited
teleport option.  Limited to once in a while, spawning-run, short jaunts
from atmosphere to Lagrange Point.  (Trick here is to avoid vampires having
teleport on demand capability, which does not seem supported by the texts:
although it would give another infusion to alga's heresy that "Pike's
ghost" in the manteon really was Q himself; since the "aquastor" dissolve
could then be a teleportation effect.)  Then they "fly" across the
distance, exposed to vacuum, and do the long glide in.  (I hadn't even
thought to tie-in the Neighbors, with their clear and obvious
astral/teleport powers [Horn into Silk]; nevermind the seeming
teleport-link between Horn/Silk and an inhuma for all of his "astral
projection" jaunts.)

I was going to prep it by saying, "Look, when the undines of Urth say they
can swim through space and/or the corridors of time, we don't spend any
time working out the escape velocity, etc., because (while at first we
think they are speaking metaphorically and later, when we see that it is
real . . . ) we see it as technology so advanced that it is magic to us.
Some form of teleportation (through space) and/or time travel (itself
magic).  We don't argue about the possibly implied differences between
`walking' the corridors and `swimming' the corridors."

FWIW digression: The time-travel in Severian's narrative seems to have
elements of pseudo-momentum or pseudo-inertia involved: when the power
stops, the traveler doesn't necessarily stop immediately.  Hence in URTH
when Sev was leaving the deluge by `running' back into the far past, he
reached the endpoint (light of the white hole reaching Urth) and was
catapulted (a hundred years?) beyond, presumably by the pseudo-velocity of
his `running.'

Then I was going to say, "So while I'm toying with this in a light-hearted
fashion, I'm not really too concerned, myself, with the mechanics of it.
Not to criticize anybody who is pondering it more seriously."

(Then again, wombat: don't wings and lifting bodies have an atmospheric
limit?  That is, they have no value in a vacuum, and as the object comes
into the gravity well it picks up some speed before the atmosphere is
sufficiently thick enough to provide the lift?  I guess I'm saying there's
enough atmosphere for re-entry friction, but not enough for lift, until the
object gets to a certain critical level which is relatively deep into the
gravity well: but I'm just wondering around.)

=mantis=

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---

From: Alastair Reynolds <areynold at estsa2.estec.esa.nl>
Date: Wed, 06 Sep 2000 07:19:46 +0000

Michael Andre-Driussi wrote:

> gravity well: but I'm just wondering around.)

No; you're right, Mantis - if the inhumi "fall" from the lagrange point
between
Green and Blue, then they're essentially going to hit Blue's atmosphere
with speed on the order of escape velocity. The only thing they can
modify,
assuming they don't have a way to slow down in vaccum (stolen PM modules
from the Trivigaunti fliers?) is their angle at which they brush the 
atmosphere. And even with the optimum approach angle (not too steep so
that they burn up, or too shallow so that they bounce off), there'll
still be an enormous amount of friction. Somehow or other the kinetic
energy they've accumulated during their fall has to be converted to
heat, and the only variable is whether this happens slowly, in a
controlled
way (like a space shuttle re-entry) or in a quick burn-up. Barbecued
inhumi, anyone?

Re: the orbital mechanics of Green/Blue - wasn't the best explanation,
as worked out by someone here, that they're analogous to our moon and
its small satellite partner Cruithne? It was pointed out that this
had been written up (in Nature I think) early enough for Wolfe
to have incorporated it into the series. Or was there some
fatal flaw in that idea?

Al

---

From: Kevin J. Maroney <kmaroney at ungames.com>
Date: Wed, 06 Sep 2000 12:18:11 +0000

At 09:19 AM 9/6/00 +0200, Alastair wrote:
>between Green and Blue, then they're essentially going to hit Blue's
>atmosphere with speed on the order of escape velocity. 

Agreed. I've been assuming that they don't fall from that distance. There
are three basic possibilities, as I see it: 

The inhumi move from planet to planet via traditional ballistics, which
requires them to reach some high percentage of escape velocity from Green
and absorb that kinetic energy at Blue; 

The inhumi are under some sore of controlled flight for the entire trip
from Green to Blue and vice versa, but with an unknown mechanism; or 

That they teleport most of the distance via some gift from the Neighbors
and only fly within the atmospheres of the two planets. 

I'm actually most inclined to believe the third. I have a suspicion that
the Neighbors evolved on Blue, the inhumi on Green, and they only came into
contact with each other after the Neighbors tried to conquer Green,
relatively recently. The Neighbors do not perceive distance the way humans
do. The inhumi gained a great deal from the Neighbors, as Horn has; the
evidence in _Green_ is that some of that difference can be communicated to
humans and almost certainly to inhumi as well. 

This scenario also helps explain how Quetzal and his kindred came on to the
_Whorl_ despite its tremendous distance from Green. 

I don't think that the inhumi can teleport at will. Fava's surprise at
Incanto's ability demonstrates that. But I think they might be able to slip
from place to place. 

-- 
Wombat, a.k.a. Kevin Maroney kmaroney at ungames.com
Kitchen Staff Supervisor, New York Review of Science Fiction
http://www.nyrsf.com