I'll just address your closing comments that you'd never heard of Ringworld
before.  Larry Niven was essentially a mathematician before he got in to
writing "hard" scifi.  He's slacked off the last 10 years, but his earlier
stuff is really good because he's got a lot of good hard science in
them.  You should check out the original ringworld novel because he spends
a good bit of time discussing and justifying the science, which is why I
questioned the ocean situation.  I know you are all edumacated and stuff on
this, but I learned most of my science and physics from scifi and comic
books :)

At 07:32 PM 9/23/2004, [log in to unmask] wrote:
>Shawn asks:
>
> > >The only real strength that would be required in the structure is that you
> >  >would want your 1 gazillion plates that you've somehow welded
> together to
> >  >strong enough so that they didn't dent when you jumped up and down ("up"
> >  >towards the central sun).
> >
> >  wow, so you could have an ocean in a configuration like that?  I kind of
> >  figured a bazillion gallons of water in a bowl being pulled out by the
> >  sping of the ring would require a really strong structure.
>
>Yes. The surface tension of the water would allow it to remain in a perfectly
>circular orbit as a fluid rope around the central sun. But that's not to say
>that it wouldn't eventually evaporate. The sun would still heat and
>photodissociate individual water molecules to the point of escape
>velocity, just the Sun
>is doing so to the Earth's oceans now. In 500 Myr to 1 Gyr, the Earth's
>oceans will disappear and this planet will look much like either Venus or
>Mars,
>both of which once had their own oceans but lost theirs two to three billion
>years ago.
>
>Thinking about this a little further however, not only is there no great
>tensile force running laterally through the ring, neither is there any radial
>restoring force that approximates "gravity." If you jumped "up," towards the
>central sun, all that you would be doing would be changing your orbital
>path, ever
>so slightly increasing your speed relative to the "ground." You would simply
>float in that position, laterally skimming the "ground" below. After one full
>trip around the ring, you would come back to the exactly same position from
>where you jumped, and return to the same aphelion (distance from the central
>sun), so that you would impact the ring at the exact spot from which you
>originally leapt.
>
>If there is to be any "gravity" in this situation, it would be on the outside
>(the darkside) of the ring. If you jumped "up", you would fall back towards
>the common center of mass of the distant sun and the ring and be
>intercepted in
>your path by the ring material. This is exactly what happens when you jump up
>on Earth. For a moment, you're orbiting the center of mass of the Earth. It's
>only an unfortunate consequence of the Earth getting in the way that you
>don't complete your orbit. But on a low-mass ringworld, the effect won't
>be much
>and you will land with a very light touch.
>
>I don't know if this is the physics that is used in "Ringworld," but if there
>are to be people in this "ringworld," they'd better be in a tube and be used
>to near zero-gravity conditions.
>
>I'd never heard of the story before a couple of weeks ago, when a reporter
>asked the panel during a NASA news conference concerning the recent
>discovery of
>several new exoplanets if anyone thought that a "ringworld" was possible.
>Clearly neither had obviously Geoff Marcy, famed planet hunter and the
>co-discoverer of about 100 of these extrasolar planets. He gave a fairly
>long and
>technically correct answer, talking about a number of planets that had been
>discovered that appear to be tidally locked to the their central suns, so
>that one
>face always faces the sun, just as the Moon is tidally locked to the
>Earth. Many
>of these planets are very close to their suns, so that the surface facing the
>sun would be molten. On such worlds, the sun will stand still in the sky,
>never moving much (not moving at all if the planet is in a perfectly circular
>orbit). Marcy went on to explain that in these circumstances that there
>would be a
>ring of positions around the planet, between the light and dark faces of the
>planet, where the sun would appear perpetually on the horizon, in perpetual
>twilight, and in this ring of spaces, the planet might be habitable.
>
>Anne Kinney, who is the director of the astronomy and physics division of
>NASA space sciences, and who obviously reads more science fiction than either
>Marcy or I do, mentioned that everything Marcy had said was correct, but
>then she
>went on to briefly explain the story, thus everything I know about the story
>comes from those few sentences of just a few days ago.
>
>Wirt Atmar


Regards,

Shawn Gordon
President
theKompany.com
www.thekompany.com
949-713-3276

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