Re: Exotic gravities: planes, lines, radiants, etc

Here, Jack Bohn <jackbohn@xxxxxxxxxx> wrote:
Any stories dealing with such odd constructs?

Larry Niven's "Bigger Than Worlds" seemingly had both the first
and last words on the Alderson Disk, a CD-shaped world with a
hole in the middle for a sun, with gravity perpendicular to its
surface, and a sun perpetually on the horizon, unless we bob it
up and down for brief sunrises/sunsets. To give you an idea of
the mass of the thing, it is the sun moving.

On RASFS, Erik Max Francis, I think, did some Mathematica renderings
of how the gravity would work. It comes out to be less perpendicular
than you might wish.

And if we can keep such a thing from collapsing into a sphere,
surely we can join six smaller ones together into a cubeworld...

Well, now you've just got a cubical planet. Which is to say, a planet
with eight enormous mountains that stick up out of the atmosphere.

A linear sun would, with its light falling off only linearly with
distance, have a much wider habitable zone than ours, although I
hesitate to guess what a transfer orbit between planets would
look like, with gravity also only falling linearly.

It's not obvious what *any* orbit would look like -- you don't get
ellipses. Dewdney worked it out for _Planiverse_ but I forget the
answer.

At least I
expect these planets would be easier to get to than the next
"stack" of orbits threaded along a really long linear sun.

Moving along the axis is free, remember. (Helical orbits work! Use an
angled solar sail to get axial boost, and then wait.)

The final exotic world I can think of is that of the radiant from
Fred Saberhagen's "Some Events at the Templar Radiant." It's a
point source that pushes everything away from it, and some
ancient race was able to build a shell around it to trap its
energies. Aside from being an inside-out world, I don't recall
any other peculiarities.


Anything else?

Priest's _Inverted World_.

The boring Baxter book where gravity was inverse square, but vastly
more powerful, so a "solar system" was human-scale. Or maybe it wasn't
inverse square. I don't remember the details, because it was dull.

--Z

--
"And Aholibamah bare Jeush, and Jaalam, and Korah: these were the borogoves..."
*
.

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