In article <10btv5v$fr5$1@reader2.panix.com>,
jdnicoll@panix.com (James Nicoll) wrote:

In article <robertaw-4DB75F.22113704102025@news.individual.net>,
Robert Woodward <robertaw@drizzle.com> wrote:

In article <robertaw-0A4722.23132121082025@news.individual.net>,
Robert Woodward <robertaw@drizzle.com> wrote:

Note: I decided to repost this since Freeman Dyson didn't postulate a
hollow shell, but a massive swarm of objects.

The short version: this book was a disappointment.

About 2 decades ago, Stirling wrote 2 books that modernized the mid 20th >> century Planetary Romance genre (_The Sky People_ and _In the Courts of >> the Crimson Kings_). Both Venus and Mars had been terraformed during the >> Mesozoic by a highly advanced interstellar civilization and had been
seeded by life from Earth (with periodic inserts of more species,
including humans, up to about 5 thousand years ago for Venus and perhaps >> 200 hundred thousand years ago for Mars). The most advanced cultures on >> Venus were Bronze age, but Mars had a uniform civilization with
extremely advanced bio-tech on a dying planet. In the epilog of _In the >> Courts of the Crimson Kings_ some gates were opened that connected Venus >> and Mars to other worlds, and Earth to a hollow sphere, 2 Astronomic
units in diameter.

These two books have recently been reprinted by a new publisher and
Stirling wrote a 3rd title, _Lords of Creation_ to go with them. People >> are exploring that sphere, but NONE of them appear to be aware
that a hollow sphere has no internal gravity force. They are all walking >> around in a 1 g field.

Oops, I made a mistake above. I was looking for something else in this >title and noticed Stirling's handwave (which I had somehow missed when I >read the book). The people are unconcerned because they know what they
are walking in (at least they have a photo from a big telescope of an >object of the right size whose interior would have the apparent 1 g
field they are experiencing). What Stirling has is a big hollow sphere >that is rotating and has large protrusions at the poles (large enough to >be seen in the picture). Result, 1 g everywhere on the interior surface.

That will only produce one gee for regions at a specific radius to
the axis of rotation. Regions closer will have less and regions
farther will have more.

Those large protrusions were MASSIVE*. There was a 1 g force outward at
the poles. I have no idea if the shape described would produce the
results described, but there was a gravitational vector** added to the centrifugal force vector at every point in the interior sphere resulting
in an 1 g force normal to the interior shell of the sphere.

*Massive for values equal to many solar masses (best guess). This is why
I think the object would collapse into a solid sphere (before becoming a
black hole).

**Since the gravitational vectors were not generated by two point
sources, they do not converge.

--
"We have advanced to new and surprising levels of bafflement."
Imperial Auditor Miles Vorkosigan describes progress in _Komarr_. ?-----------------------------------------------------
Robert Woodward robertaw@drizzle.com

--- PyGate Linux v1.0
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)