| Wednesday,
March 7, 2007
Subject: Spirals
As you may have surmised from the subject line I
am reading an anthology which includes "Spirals". The thing drove me bonkers
20 years ago, and it still does. How you and Niven could produce such a
colossally, dismally stupid piece of......Oops. Just a moment. There. I'm
OK, I'm OK. I think it's the hens. The chickens who mysteriously experience
a change in gravity at various heights. And you 2 brilliant guys batted this
idea around for God knows how long. It just boggles the mind. Jerry, babe,
I'm gleeful to have this opportunity to explain to you that spinning the
habitat around does not generate gravity. There is no field of gravity. No
field of gravity to change at various heights. It is true that many of
gravity's effects are simulated, but it takes some careful thinking to avoid
the trap the you and Niven fell into: Describing events that could only have
occurred in a gravity field. Where that chickenpoop would acually have gone
is a question tantalizingly beyond my perceptual skills, but I can tell you
what would happen to a man who stepped out of a door, say, 2/3 of the way up
to the axis, into open air, with no floor under his feet: He would
immediately fly off on a straight tangent perpendicular to the radius (a
line from the axis to the circumference as viewed from either pole). As he
flew sideways the floor far "below" would move to meet him and he would land
(I think) on the spot that was "below" him when he jumped. And here's one
way he would know he was not in a gravity field- he'd land on his side! So
nyah!nyah!
Jerry Neagle [popadoob@sonic.net]
I first wrote a reply in the same tone as
your letter, but that was rude.
You have not sufficiently analyzed the
situation; you confuse what would be seen by a stationary observer outside
the rotating cylinder with what is seen by a rotating observer inside the
system. Inside the system, if you drop a ball from, say, eye-height, it will
appear to fall down towards your feet. It won't hit at your feet, for the
obvious reason that your feet are traveling faster than your eyes. Thus
although the ball travels in a straight line perpendicular to the axis of
the ship (you are certainly correct there) it appears to fall in a slightly
curved trajectory since the floor runs away from the ball. Playing baseball
on an O'Neill Colony would be interesting for pitcher, batter, and fielders.
Incidentally, if you throw the ball in the
direction of rotation it will have a different apparent trajectory than if
you throw it perpendicular to the rotation; I leave that to you to work out.
The question is, what makes for the most interesting orientation for the
baseball diamond?
Clearly, the larger the Colony, the slower
the rotation, and the smaller the apparent effects of all this when
you are close to the outer shell. Equally clearly, things get stranger as
you get closer to the center (Joe-Jim's kingdom of no-weight in Universe).
There is a very great deal about
centrifugal gravity here:
http://www.projectrho.com/rocket/rocket3u.html
including a number of quotes from
different sources. One of those quotes is:
From A STEP FARTHER OUT by Jerry
Pournelle, 1979. This is science fact, not science fiction.
And prior to (the) Mercury (program) we hadn't any
real experience at all. We flew
transport planes in parabolic courses
that might give as much as 30 seconds of almost-zero-g, and that was all we
knew. I will not soon forget some of our early low-g experiments. Some
genius wanted to know how a cat oriented: visual cues, or a gravity sensor?
The obvious way to find out was to take a cat up in an airplane, fly the
plane in a parabolic orbit, and observe the cat during the short period of
zero-g.
It made sense. Maybe. It didn't make enough that anyone would authorize a
large airplane for the experiment, so a camera was mounted in a small
fighter (perhaps a T-bird; I forget), and the cat was carried along in the
pilot's lap. A movie was made of the whole run.
The film, I fear, doesn't tell us how a cat orients. It shows the pilot
frantically trying to tear the cat off his arm, and the cat just as
violently resisting. Eventually the cat was broken free and let go in
mid-air, where it seemed magically (teleportation? or not really zero
gravity in the plane? no one knows) to move, rapidly, straight back to the
pilot, claws outstretched. This time there was no tearing it loose at all.
The only thing I learned from the film is that cats (or this one anyway)
don't like zero gravity, and think human beings are the obvious point of
stability to cling to...
We actually ran that experiment at least twice. Once was at Randolph AFB
using the Officer's club cat as the subject during a T-bird proficiency
flight. I guess it is long enough ago to release a couple of details...
(While you are at it, you might look at
http://www.projectrho.com/SSC/index.html )
I haven't dealt with centrifugal gravity
in a while, but I used to work those problems in some detail. We got it
pretty well right in Spirals. Whether you like the story or not is another
story: there's a story that goes with the writing of that story. It involves
a Houston restaurant, a very expensive mink coat, and dinner in the wrong
part of town; one of these days I may tell the story.
But in any event, I'm pretty sure I got it
right in the story; your problem is you confuse a stationary and a rotating
frame of reference. In the rotating frame of reference, there is "gravity"
mitigated by the "Coriolis Force" (there is no such "force"; it's a result
of the rotating frame of reference.
Note also that the atmosphere inside a
large space settlement as described in Spirals is also rotating, while your
acrobat who stepped off the ladder is no longer subject to that. I leave the
resulting wind resistance as an exercise for the readers.
There is more discussion of this at
http://www.phy6.org/stargaze/Lrotfram.htm which is a high school level
lesson on centrifugal gravity.
Physiologically, the one thing you need to
know is that centrifugal gravity requires a reasonably large radius ship.
Trying to get a significant centrifugal gravity by rotating a small cylinder
fast will not work, and as you get a smaller radius and a higher rotation
speed, you end up in conditions in which Coriolis forces induce a water
hammer effect that will give you a stroke from bending over.
Googling "centrifugal gravity" gives a
fair number of sites of some interest to those who want to know more.
========
Subject: Inuit people are using air conditioners. Give
me the Nobel Peace Prize!
Dear Dr. Pournelle,
Did you see this?
"How hot is it? So hot that Inuit people around the
Arctic Circle are using air conditioners for the first time. And running out
of the hard-packed snow they need to build igloos. And falling through
melting ice when they hunt.
These circumstances are the current results of global
climate change, according to Nobel Peace Prize nominee Sheila Watt-Cloutier,
an Inuit born inside the Canadian Arctic, who maintains this constitutes a
violation of human rights for indigenous people in low-lying areas
throughout the world.
Watt-Cloutier and Martin Wagner, an attorney with the
environmental law firm Earthjustice, argued this case on Thursday before the
Inter-American Commission on Human Rights of the Organization of American
States in Washington."
<http://www.alertnet.org/thenews/newsdesk/N02270269.htm>
A. Romain
I am not sure I understand this.
========
Subject: "They were murderers like any other
murderers."
"They were murderers like any other murderers."
http://www.washingtonpost.com/wp-dyn/
content/article/2007/03/03/AR2007030300979_pf.html
-- Roland Dobbins
My daughter was in Army Intelligence in
those days.
=========
Subject: CBS and the Hallucinations,
Jerry
"For those stricken with [CBS], the world is
occasionally adorned with vivid yet unreal images."
http://www.damninteresting.com/?p=604
This would explain things.
Ed
Now, now...
=========
Subject: MIT OCW vs, Podunk Jr.
College
Dear Jerry,
>
Imagine a company that hired someone who can show he has done all
the work of an MIT degree, but does not have the paper, in preference to
a minority graduate of Podunk Junior College but has a certificate. The
company would be sued into bankruptcy. <
Why not imagine a company that hires both candidates
in an entry-level position, and lets them fight it out according the classic
survival principles of Darwin? Are you absolutely SURE that the one who
understands the MIT material is going to do a better job for the company? In
the meantime, the Podunk Junior College grad on the payroll is solid proof
that the company does not engage in discriminatory hiring policies.
Betty Strohm bstrohm@juno.com
You may print this if you wish.
I cannot imagine a company doing that;
what I can imagine is lawyers getting rich, only I don't have to imagine it
because I have seen it happen. Of course I am not absolutely sure of which
one would be better at the job. I don't know any personnel selection systems
that would assure that result. What I can be certain of is that this is not
what the Framers would understand as freedom or liberty.
==========
Harry Erwin's Letter
from England
Subject: Letter from England (no image version)
I spent the weekend at a church retreat in
Scarborough, so this letter is a bit delayed. Scarborough is a traditional
seaside spa in Yorkshire, with a castle on the cliff over the town and
various parts of the resort for various classes.
News:
School issues <http://news.bbc.co.uk/1/hi/education/6413811.stm>
<http://news.bbc.co.uk/1/hi/uk/6416967.stm>
<http://news.bbc.co.uk/1/hi/england/berkshire/6417639.stm>
<http://news.bbc.co.uk/1/hi/education/6413265.stm>
<http://news.bbc.co.uk/1/hi/education/6409771.stm>
<http://news.bbc.co.uk/1/hi/uk/6417565.stm>
<http://www.guardian.co.uk/Observer/uk_news/story/0,,2026176,00.html>
<http://education.independent.co.uk/news/article2323403.ece>
Cash for honours <http://news.bbc.co.uk/1/hi/uk/6416657.stm>
<http://www.telegraph.co.uk/news/main.jhtml?xml=/news/2007/03/03/
nhon103.xml> <http://www.telegraph.co.uk/news/main.jhtml?xml=/news/2007/03/04/
nhons04.xml> <http://news.independent.co.uk/uk/politics/article2326228.ece>
<http://news.independent.co.uk/uk/legal/article2323479.ece>
NHS problems <http://www.guardian.co.uk/Observer/uk_news/story/0,,2026239,00.html>
<http://www.telegraph.co.uk/news/main.jhtml?xml=/
news/2007/03/02/ nprescription102.xml>
<http://www.telegraph.co.uk/news/
main.jhtml?xml=/news/2007/03/01/ npay101.xml>
<http://news.independent.co.uk/uk/health_medical/article2326233.ece>
<http://news.independent.co.uk/uk/health_medical/article2326232.ece>
<http://news.independent.co.uk/uk/health_medical/article2326231.ece>
<http://news.independent.co.uk/uk/health_medical/article2318737.ece>
Contaminated petrol <http://www.guardian.co.uk/Observer/uk_news/story/0,,2026304,00.html>
<http://www.telegraph.co.uk/news/main.jhtml?xml=/news/2007/03/02/
nsilicon102.xml> <http://www.telegraph.co.uk/news/main.jhtml?xml=/news/2007/03/01/
nfuel301.xml> <http://www.telegraph.co.uk/news/main.jhtml?xml=/news/2007/03/01/
nfuel201.xml> <http://news.independent.co.uk/uk/transport/article2323460.ece>
<http://news.independent.co.uk/uk/transport/article2326237.ece>
Eliminating the Privy Council
<http://www.telegraph.co.uk/news/main.jhtml?xml=/news/2007/03/04/
nlords204.xml>
MI5 trains supermarket staff to detect terrorists <http://news.independent.co.uk/uk/crime/article2326211.ece>
Walter Reed story in the UK <http://observer.guardian.co.uk/world/story/0,,2026080,00.html>
Research funding slashed in the UK
<http://www.thes.co.uk/current_edition/story.aspx?story_id=2035565>
<http://news.bbc.co.uk/1/hi/sci/tech/6419261.stm>
Commentary:
Not much to comment on this eek--perhaps the situation
is best described as desperate but hardly serious. The budget is a serious
problem, but that reflects more of a political unwillingness to face reality
than a lack of resources or management options. If people of faith could
figure out a viable programme to deal with social alienation, it might be a
serious challenge to business and politics as usual, but in the interim,
nothing is changing.
-- Harry Erwin, PhD, Program Leader, MSc Information
Systems Security, University of Sunderland.
<http://scat-he-g4.sunderland.ac.uk/~harryerw> Weblog at: <http://scat-he-g4.sunderland.ac.uk/~harryerw/blog/index.php>
==========
Subject: Such a certification program exists...
"What's needed is some way to certify credentials that doesn't involve
the expense of going to a modern university. We need a system that will do
that: that will allow people to learn something, get certification that they
know it, and have that count when the racial profilers count up the quotas
in employment."
At least in part such a system already exists:
http://www.collegeboard.com/student/testing/clep/about.html
Scott Kitterman
> Ain't the same, is it? I don't think having
that is the equivalent of having a degree for purposes of escaping
affirmative action lawsuits.
Jerry Pournelle
Chaos Manor
Not precisely, but you can use clep credit to count towards getting such
a degree. You can't escape the credential system entirely, but you can, in
part, leverage your experience to get such a credential.
It is ironic that I work as a consultant doing work I am good at and can
charge a good rate for (because I'm good at it) when I would be manifestly
unqualified for doing the same work as an employee because I lack the proper
credentials. It works out well enough for me. I get to charge consulting
rates and work from home....
Scott K
Which was my point. You can kick against the
pricks, but the fact is that the credential people own the system, and any
company that tried to buck that will be punished. The remedy is to move the
jobs out of the United States, and we are rapidly doing that. The costs of
political correctness are far greater than most suppose.
========
Subject: Horrors of Global Warming... The article at
http://www.alertnet.org/thenews/newsdesk/N02270269.htm shows many
horrors.
The Inuit hunter/gatherers are described as "living
sustainably". Remember this next time some evangelical environmentalist says
"sustainable". They mean "reduce to crushing poverty".
The shelter the Inuit constructed to keep the cold out
are rendered unnecessary because now warmer summers mean that less intense
construction methods will do.
Ice is thin enough to penetrate without heavy
equipment.
Change is occurring, and some people are having a hard
time adapting.
Will Albenzi PS, at this end of the Hockey stick, we
just had a wonderful quote ""This is the coldest weather we've seen on Mount
Washington since January 25, 2004,"
John
=========
Subj: Victor Davis Hanson on _300_
http://corner.nationalreview.com/post/?q=
YzJmOTNmYmNlYjNmMDIyZjNmMWRjOG
ExOGNjYzBjMzU=
=[I]in an eerie way, the film captures the spirit of
Greek fictive arts themselves. Snyder and Johnstad and Miller are Hellenic
in this sense: red-figure vase painting especially idealized Greek hoplites
through "heroic nudity". Such iconographic stylization meant sometimes that
armor was not included in order to emphasize the male physique.=
=[W]hat was not conventionalized was the martial
spirit of Sparta that comes through the film. Many of the most famous lines
in the film come directly either from Herodotus or Plutarch's Moralia, and
they capture well, in the historical sense, the collective Spartan martial
ethic, honor, glory, and ancestor reverence (I say that as an admirer of
democratic Thebes and its destruction of Sparta's system of Messenian
helotage in 369 BC).=
=Ultimately the film takes a moral stance, Herodotean
in nature: there is a difference, an unapologetic difference between free
citizens who fight for eleutheria and imperial subjects who give obeisance.
We are not left with the usual postmodern quandary 'who are the good guys'
in a battle in which the lust for violence plagues both sides. In the end,
the defending Spartans are better, not perfect, just better than the
invading Persians, and that proves good enough in the end. And to suggest
that ambiguously these days has perhaps become a revolutionary thing in
itself.=
Rod Montgomery==monty@sprintmail.com
A long time ago on a research trip through
Greece I visited Thermopylae. It's different now. A superhighway runs
through it now.
I told of this a good time ago:
http://www.jerrypournelle.com/archives2/
archives2mail/mail435.html#subjects
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