Conference noted::sf

I have heard dim rumors for mechanisms for the generation of artificial 
gravity.  They come mostly from an old Analog science fact article, year and 
number long forgotten.  I have heard corroborative things from other sources.

The general idea is that, just as eletrical fields in motion produces a
magnetic field, so gravitational fields in motion produce an analogous field 
-- much too weak to be noticed in ordinary life.  In particular, spinning 
masses tend to make nearby masses move around them in the direction of spin.  
I think.  (Repeat: all of this is terribly hazy in my memory.)

The upshot of this is that it might be possible to create gravity generators 
by, say, imparting fantastically high spin to the particles constituting the 
core of the generator.  The resulting artificial gravity field would consist 
of closed lines of force, like a magnetic field.  By suitable arrangement of 
generators, you could shape the gravity field in the same way you shape a 
magnetic field.

One result is that a "bar gravitet" has two poles, like a magnet, only these 
are attractive and repulsive gravity.  The two poles would behave like 
positive and negative masses (see previous topic) with the inert positive mass 
of the generator slung between them.  The positive pole will attract the 
negative pole, while the negative pole repels the positive one.  As you pour 
energy into the machine, it turns into kinetic energy and the system moves, 
positive pole forward.  I don't know how momentum gets conserved under such 
circumstances.  Perhaps this indicates a fatal flaw, or perhaps momentum is 
conserved by the way the generator pulls and pushes on the gravity fields of 
the surrounding universe.

Anyway, you have a gravity drive.  Smaller versions, arranged like the plates 
of a capacitor, could give you cabin gravity.  Installed in the walls and 
controlled by simple feedback circuits linked to an accelerometer, the device 
gives you acceleration compensators.

The "gravity step" going from one cabin gravity to another sounds quite 
realistic.  Kirk would tend to "fall into" Spock's cabin, and have to "climb 
out of" it.  Consider: Kirk starts to move into the cabin.  His right leg is in 
the 2g field.  Suddenly, it weighs twice as much as usual.  Kirk gets pulled 
down by his leg.  Any other portions of his anatomy that happen to flail into 
the 2g field also start pulling.  The net effect is to suck him into the 
cabin.

If I were as rich as Starfleet seems to be, I'd install a lock in front of 
cabins with independent environments.  This would act as an airlock, of 
course, but would also move one from 1g to 2g all over, instead of by an edge. 
It would be the same sort of difference as exists between going through a 
canal lock and going over a waterfall.

Earl Wajenberg

    Wow, that is really something.  I have enough problems trying to
    keep up with advancing computer technology, so I had no idea any
    kind of gravitational work like that was going on.
    
    I like the idea of a "gravity lock", it sure beats going over that
    waterfall.
    
    Thnx,
    
    fw

    Robert Forward returns to Dragon's Egg in _Starquake_. The Appendix
    of this book describes a few gravity machines invented by the Cheela.
    One being a time machine, the other being a hyperspace gate. Both
    of these require ultra-dense matter like neutronium to work.
    
    Any gravitational engineers out there should read this book.
                                                   
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    RE: 1 
     Your idea about spinning masses creating gravity fields sounds
    elegant because of the analogous electrical fields in motion producing
    a magnetic field.  But then my question would be could this idea
    be proven by observing spinning neutron star (pulsars) and how they
    effect matter around them? Maybe astromony holds the answer to such
    questions.

    re .0:
    
    no, a spinning sphere would not "drag" any satellites in the direction
    of rotation. 
    
    the satellite would feel a force pushing "downward" (perpendicular
    to the orbital plane) this force would cause the orbit to tilt and
    precess. There should be no preference of direction of the the orbit
    though.
    
    The neat effects occur when you have a spinning torus (or get really
    wild and stack them up to form a solenoid) and then put something
    into the center.
                                                   
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    Re .5
    
    I am puzzled by the effect you describe.  What causes the push
    perpendicular to the orbital plane?  Also, there are two perpendicual
    directions that qualify equally -- north and south.  It feels very 
    asymetrical that there should be a force from, say, the north rather
    than the south.
    
    I've searched my memory a bit more and I believe that there IS a
    drag in the direction of rotation.  At least, one is predicted by
    general relativity.  I could try checking through my library...
                                                                   
    Earl Wajenberg

    re .6:
    
    .5 is based on visualizing the magnetic field lines produced by
    electrons flowing around a ring. Imagine the spherical planet replaced
    by a solenoidal coil. the coils enlarge toward the center to produce
    the sperical shape. To "set the sphere spinning" run a current through
    the coil. Now, examine the field lines surrounding our spherical
    solenoid. As we move out radially from the equator, the field lines
    are perpendicular. whether it is north or south pointing depends
    on the "handedness" of the system.
    
    I asssumed that the force will be felt parallel to the field lines,
    but maybe not, if the force is a cross-product, then the force will
    be felt in the radial direction (again the direction depends on
    the handedness). In neither case is the force felt in the tangential
    direction. 
    
    Of course this is merely analogizing to the case of electro-magnetism,
    for which there is little or no justification.
    
    I would be very interested in seeing what general relativity has
    to say about this.
                                                   
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    re the spinning torus - it's my understanding that the torus has
    to be "spinning" like a smoke ring, i.e., so the surface is moving
    parallel, perpendicular and antiparallel (inside, top/bottom, outside)
    to the central axis of symmetry, rather than uniformly perpendicular
    (albeit with changing orientation) to it.

    Can anybody explain why?  And just what happens when you thread
    the eye?
    
    len.
    

 On a slightly different tangent, I remember reading a short
story where 'the government' conned a group of scientists into
thinking that anti-gravity had already been discovered by an
inventor who had promptly killed himself flying the contraption.

Anyway the scientists went off and discovered anti-gravity because
they now 'knew' that it was possible.

Anyway this anti-gravity unit using a spinning taurus sounds great
but I do have one question.  Does this mean that the person
living in the room undeneath Spocks room would be feel 2 Gs standing
on their floor or ceiling?

    Using the speculative physics under discussion, the person one deck
    down from Spock would indeed get extra gravity unless precautions
    wre taken.  The precautions could get elaborate.
    
    There are substances that block magnetic or electric fields because,
    when exposed to the field, they develop a countervailing field of
    their own.  Using a similar principle, Spock's cabin (or each cabin
    on the ship) could be insulated by arrays of gravity generators
    with simple sensors and feedback circuits, working in much the same
    way as the acceleration damper I mentioned earlier.
    
    Here's another gravitic device, in fact a candidate for the doubly-
    fictitious craft that "killed" the made-up scientist you mention:
    When gravitics is in an early, primitive stage of development, it
    might be too hard to lift a vehicle straight off the ground.  Instead,
    you could build an airplane like unto a jet, substitute gravity
    drives for the jets, and use them to develop thrust, not lift. 
    That's assuming a gravity generator can be built the size of a jet
    engine and deliver at least as much thrust.
    
    Earl Wajenberg

    re .8:
    
    > re the spinning torus - it's my understanding that the torus has
    > to be "spinning" like a smoke ring, i.e., so the surface is moving
    > parallel, perpendicular and antiparallel (inside, top/bottom, outside)
    > to the central axis of symmetry, rather than uniformly perpendicular
    > (albeit with changing orientation) to it. 
    
    I don't want to sound too self-important, but I may have generated
    this mis-conception in the Note titled "Larrydrive". 
    
    I wrote the note there before reading _Starquake_. 
    
    As for what happens when you "thread the eye" is a massive
    gravitational acceleration, and since you "free-fall" through it,
    you get no nasty effects like being squashed. Thus, you can be
    accelerated up to near light-speed in a very short distance (and
    time) and feel no ill-effects.
                                                   
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    Re .9:
    
    That "spinning taurus" stuff is a lot of bull! :-)
    
    Steve Kallis, Jr.
    

    
    Last I heard, there was still no empirical evidence whether gravity
    is transmitted by way of a wave, particle, or something new.
    A lot of work has been done to detect a gravitational wave and all
    experiments have failed. (as far as i know)
    
    Being an SF fan I would like to think it is something different
    than a wave or particle.  Neither of which yield a straightforward
    method of control.
    
    Steve McAfee
    

    re .13:
    
    Be careful about speaking of waves and particles as though they
    are seperate entities, otherwise someone like me will jump all over
    you :-)
    
    I don't think the experiments have really "failed", they are just
    too noisy. Remember, gravity wave detectors are *VERY* good
    seismographs. Besides in order to detect the wave, some sort of
    gravitational event must occur, like the collapse of a massive star
    into a neutron star. These do not happen frequently or nearby.
                  
    > Being an SF fan I would like to think it is something different
    > than a wave or particle.  Neither of which yield a straightforward
    > method of control.

       Lets see, how does being a wave/particle imply no easy method
    of control. We control photons pretty easily. Same could one day
    be said of gravitons.
    
                                                   
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    There has been a little indirect evidence of gravitational radiation.
    Any accelerating body should give off these G-waves.  Anything in 
    orbit is accelerating and should thus radiate in the G-spectrum, but
    most would do so at a very low energy, too low to detect with current
    technology.
    
    A year or so ago, some astronomers observed a slow decay in the
    orbits of twin neutron stars.  Within the accuracy of their
    observations, the rate of decay agreed with the amount of energy
    they should be losing by gravitational radiation.
    
    Earl Wajenberg

Re .15:

    The same argument was applied to electrons 'orbiting' in atoms. According
to unvarnished electrodynamics, they should radiate photons.  The fact is that
they do not.  The lack of observed gravitational radiation is an indication 
that our understanding of gravity is incomplete.  The match between the decay 
of orbits and gravitational radiation rates could be a coincidence.  After 
all, pure chance indicates that one in 20,000 sets of unrelated events will 
correlate with significance at the .005% level.

    "The lack of observed gravitational radiation is an indication that
    our understanding of gravity is incomplete."  Yea verily.  And the
    match between observed and predicted decay COULD be coincidence.
    It still remains reasonable that it isn't.
    
    Toying gingerly with quantized gravity, we'd expect any orbiting
    body to be occupying one of many discrete "orbital shells" analogous
    to the electron shells in an atom.  But for macroscopic bodies like
    planets and stars the shells would be fantastically closely spaced,
    so that they would look continuous from a distance.  This might
    help make general relativity look as accurate as we can yet measure.
    
    Also, granting that planets and stars are orbiting in discrete shells,
    the electronic analogy still suggests they would give off gravitational
    radiation.  After all, an electron in a high-energy shell tends
    to drop to lower energies, radiating as it goes, until the electrons
    beneath it keep it from dropping any lower.
    
    Earl Wajenberg

    re .16
    
>   The same argument was applied to electrons 'orbiting' in atoms. According
>   to unvarnished electrodynamics, they should radiate photons.  
>   The fact is that they do not.
  
    I'm not sure what your point is, here. Electrons do not radiate
    photons because they are not "in orbit" around the nucleus the way
    the earth is in orbit around the sun.
    
>    The lack of observed gravitational radiation is an indication 
>    that our understanding of gravity is incomplete.
     
    Not necessarily, it could just mean our instruments aren't sensitive
    enough.
    
>    The match between the decay of orbits and gravitational 
>    radiation rates could be a coincidence.
    
    Huh? What match?
    
                                                   
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    Re: .1

    Samuel Delaney has a description of the sort of "technique" you
    describe in his book "TRITON".  Many attendant phenomena and living
    consequences are also described throughout the book.

    /Jon

    I was just wondering if there is a situation where a device to control
    gravity would defy any of the well established laws of physics.
    (Like Conservation of Mass/Energy).  I couldn't think of anything
    that would cause problems, but it did bring my attention to the
    fact that this gravitation device would require more/less energy
    in the presence/absense of massive bodies.
    
    For example:  If a ship on the surface of the earth uses a device
    to hide itself from the effects of the earth's gravity and then proceeds
    to move into a position orbitting the earth (in an inertialess manner),
    then the potential energy the ship contains in orbit must have come
    from somewhere. I suppose the gravitational device would have to
    have consumed at LEAST this much energy.  You can see that such
    a device still might not be useful in the presence of large bodies
    (like black holes).
    
    
    Any comments/corrections,
    
    Steve McAfee
                             
    

First of all, there is a difference between inertia and mass.  Removing gravity
will not change an object's inertia.

Second of all if you remove the Earth's gravity from an object it will not
go into orbit.

Would you like to try rephrasing your scenario?

Jim.

    I thought that General Relativity had established the equivalence
    of mass (as the source of gravitational force) and inertia.  They've
    done some extremely sensitive experiments to see if the two are
    not always proportional, with so far negative results (although
    I did hear of an experiment with a positive result a little while
    ago.  They postulated a fifth force to account for it, hyper-charge).
    /jlr

    In both Newtonian and Einsteinian gravitational theory, mass is
    inertia.  In fact, that is the primary meaning of "mass."  In Newtonian
    theory, mass just happened to be the source of gravitational attraction
    and there was no obvious relation to inertia.  In Einsteinian theory,
    mass just happens to warp spacetime, but the connection to inertia
    comes from that first happenstance -- motion under gravitational
    attraction is a form of inertial motion, inertial motion through
    warped spacetime.
    
    However, mass is NOT the same as WEIGHT.  Was that perhaps the intended
    distinction?
    
    Earl Wajenberg

In the current issue of "Scientific American," in the "Science and the 
Citizen" column, there is an article reporting that Bernhard M. Haisch,
Alfonso Rueda, and Harold E. Putoff are developing a theory that explains
inertia and gravitation in terms of quantum electrodynamics. 

	Writing in the February issue of "Physics reivew A," the three 
	researchers describe inertia as the consequence of the bizarre 
	subatomic happenings that take place in ostensibly empty space.  
	Quantum theory predicts that, on such tiny scales, random quantum 
	fluctuations roil the vacuum, creating a soup of virtual particles.  
	Those particles pop in and out of existence before they can be 
	directly detected.
	
	Haisch and his collaborators started by assuming the existence of such 
	small-scall electrmagnetic fluctuations, known as the zero-point 
	field.  Then they examined the effects of the field on normal matter. 
	In the middle 1970s several researchers showed that an object 
	accelerating through the zero-point field should be exposed to a glow 
	of radiation stirred up from the vacuum.  Haisch, whose background is 
	in astrophysics, wondered whether that radiation would exert a 
	"pressure" opposing the acceleration; such a pressure exactly fits the 
	description of inertia.
	
	Rueda cast those ideas in mathematical form and became convinced that 
	Haisch was on to something.  ...  The two scientists soon teamed up 
	with Puthoff, who had been exploring possible connections between 
	gravity and the zero-point field.  ...  Putoff, drawing on earlier 
	work by the late Russian physicist Andrei Sakharov, seeks to explain 
	gravity as a long-range effect of zero-point electromagnetic 
	fluctuations.  Linking gravity to the zero-point field automatically 
	draws inertia into the explanation and so naturally accounts for the 
	equivalence of inertial and gravitational mass.  ....
	
	The three researchers also look to observational support from an 
	upcoming experiment at the Stanford Linear Collider, which will 
	measure the effect of electromagnetic radiation on the apparent mass 
	of the electron.
	
	That phenomenon raises the highly speculative prospect that the 
	proper electromagnetic field could eliminate the inertia of an object, 
	thereby permitting levitation.  Controlling inertia may be possible, 
	Haisch reluctantly concedes, but "God knows if it's ever gong to 
	become a reality."

I wonder if such an electromagnetic theory of gravitation and inertia is at 
all compatible with Einstein's general relativity?  For instance, does it 
allow for the concept of a curved spacetime?  (That's a beautifully romantic 
idea I would hate to lose.)

Doc Smith would be so pleased.  This strongly resembles the inertialess drive 
he used for interstellar flight in the "Lensman" series.

Anyway, it looks like the theorists are restless.

Earl Wajenberg