Re: Just Like 1 - below?

"Frank" <fpfrankpalmer@xxxxxxxxx> wrote in message news:e9119f12-2063-4a5b-a64a-45b48d226a04@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
On Oct 8, 2:14 pm, djhe...@xxxxxxxxxxx (Dorothy J Heydt) wrote:
In article <qVcY7wMGlizKF...@xxxxxxxxxxxxxxxxxx>,
Mike Williams <nos...@xxxxxxxxxxxxxxxxxx> wrote:





>Wasn't it Frank who wrote:
>> You've got one of those cylinders rotating to simulate gravity like
>>in "The High Frontier." A worker 1/10th of the radius of the cylinder
>>from the axis drops a rivet.
>> Look out below? Not quite.

>> Look out? Yes.
>> Below? No.

>> It's easy to see what happens in a Newtonian reference frame. The
>>rivet starts out moving at 1/10th the speed at which the surface
>>rotates. It keeps on at that speed and that direction until it
>>collides with the surface .995 radii later. It's velocity when it hits
>>the surface has a vertical component of .0995 the speed of surface
>>rotation radially and .01 that speed eastward (All my rotating bodies
>>rotate eastward, just like Earth does.) Meanwhile, the cylinder
>>rotates 9.95 / 2 pi (about 1.58) times.

>> The picture in the rotating reference frame of somebody standing on
>>the inner surface is a bit more complex. The straight line of the
>>unaccelerated reference frame becomes a spiral which curls westward
>>more and more obliquely. It curls around the axis 1.58 times. Its
>>radial velocity when it hits is still .0995 the speed of rotation. Its
>>velocity westward is 99% of the eastward speed of the surface of the
>>cylinder. That is to say that you experience something not dropping
>>down but traveling mostly along the surface. (About ten feet westward
>>for every foot it drops near the end of its journey.)

>> Writers of stories set in rotating space stations tend to say
>>"centripetal acceleration [or centrifugal force] takes the place of
>>gravity" and then write as if gravity were in effect. After all, they
>>live with gravity pressing them against the floor; they know how that
>>operates. And, if you stand quite still, you can't tell the difference
>>as long as the station is large enough so that it doesn't make you
>>dizzy.

>> But motion where the floor's pressure against your feet is due to
>>centripetal acceleration is always slightly different from motion on
>>Earth. How different depends on the velocity of the motion and the
>>size -- and, therefore, rotation -- of the station. In the rotating
>>frame of reference:
>> 1) You are slightly heavier going east than you are going west.
>> 2) An increase in height means an addition of eastward velocity. A
>>decrease in height leads to an addition of westward velocity.

>> Number (2) could mess up sports in space. I wrote a story --
>>rejected, as were all my stories which got all the way to the
>>submission phase -- in which the "Coriolis force" had persuaded kids
>>in the station that head shots in soccer were beyond their skill
>>level. If soccer head shots are a problem -- and I'm not sure they
>>would be in real life; the deviation isn't that much -- imagine the
>>problems involved in basketball.

>> One place that you can see important Coriolis effects on Earth is in
>>the weather. "The High Frontier" postulated weather in their
>>cylinders. (I'm less certain. Earth weather depends on a great deal of
>>heat being radiated into space from the upper regions of the
>>atmosphere. Why should that occur in an enclosed cylinder?) If they
>>are right, the weather would be strange and, perhaps, violent. Falling
>>rain would experience air resistance, something I ignored with my
>>rivet. But the air resistance which would slow the westward movement
>>of the rain would generate a westward movement of the air. Likewise,
>>rising air would move east.

>> In the soccer story, I had a "Coriolis Fountain." This started with
>>a stream of water moving up and slightly east. It turned as it rose,
>>moved west at the top, and finally fell into a basin directly under
>>the tube which began it. The shape of the stream of water was a loop.
>>Such a fountain could be built on a rotating space station.

>There was a considerable discussion about this in the B5 newsgroups
>after the baseball practice episode of Babylon 5. A baseball hit to one
>side would appear to swing downwards much more rapidly than you'd
>expect, and one hit to the other side would hang in the air much longer.
>Possibly giving a significant advantage to either a left or right handed
>batsman depending on whether the pitcher is throwing from the North or
>South. I assume that the pitch would be aligned with the axis to
>minimise such effects.

>I imagine that for the first few hours or so fielders with Earth
>reflexes would perform absolutely abysmally, but after that they'd
>adjust to the new physics and be able to perform as well as they do on
>Earth.

>I imagine that all sports facilities like football fields and basketball
>courts would be aligned along the axis, so as not favour one end over
>the other.

It does depend heavily on what you're used to. Take the
sequence in Heinlein's _The Rolling Stones_ where Roger is
trying to persuade his sons to go to university on Earth and
do some of the things he did as a kid: play baseball, ride
horseback, swim in the ocean.

"Take baseball," Castor continued. "It's not practical. How
can you figure a one-g trajectory and place your hand at the
point of contact in the free-flight time between bases?
We're not miracle men."

"I played it."

"But you grew up in a one-g field; you've got a distorted
notion of physics. Anyhow, why would we want to learn to
play baseball? When we come back, we wouldn't be able to
play it here. Why, you might crack your helmet."

RAH got one hell of a lot of things right that others didn't
Of course, he got some things wrong. In "Moon iaHM," he had money
backed by steel on the moon retain its worth earthside more than money
which would be need to ship the steel if you ever acquired the steel.
------------------------------------------------------------------------------------

MD: Yeah, but...steel on the moon could get a "free" one-way ride to Earth as a catapult container. The catapult system needed ferrous metal in order to "grab" it magnetically and fling the container into a path for safe descent to Earth with cargo. And the catapult was powered by solar panels, as I recall (possibly imperfectly). So lunar steel was a perfectly reasonable commodity for trade and barter.

There was also a lunar currency backed by gold, which was actually hauled up to Luna from Earth and stored in the vaults of the bank for that purpose. (Hong Kong in Luna Bank, ISTR). Was it bought with the proceeds from the steel?

--
Mike Dworetsky

(Remove pants sp*mbl*ck to reply)

.

Relevant Pages