On 6 Jan, 09:21, wrote:
There is a difference between doing science and engineering and just
wishing. *If we constrain ourselves to science and engineering, we
must outline some sort of logical program for attaining our goals.
This generally requires defining clearly our terms.

Anti-gravity is not a clearly defined term. *So, we first must detail
what we mean by anti-gravity and how it relates to known laws of
physics.

We indeed have to define our terms (see further). "Antigravity"
research has been reported by Janes. It could simply mean an ingenious
way of exploiting the laws of aerodynamics, like the Coanda effect.
The defense establishment plays everything close to its chest.

Laws of physics are interesting in themselves, because they are
generally subsumed by later laws. *That is, Einstein showed us how
Newton was wrong in his view of space time relativity and energy. *He
did not say Newton WAS wrong however. *In fact, Newton's laws of
motion still stand, are stilll taught, and still are a testimony to
the genius of Newton. *That's because Einstein EXPLAINED Newton in
terms of his new ideas, and got the same results as Newton and was
then able to build on it.

So, while advances in science and technology will surely, some day
show us the error of our ways and open up new and fruitful fields of
endeavour and technique, the new science, the new technique will
subsume our present art, and our present understanding, just as
Einstein subsumed Newton.

This means that anything the clearly violates Einsteinian or Newtonian
results, must be looked at very critically.

With this in mind what can we say about anti-gravity?

Well, we must first identify what we mean by anti-gravity?

Do we mean inertialess acceleration? *For what purpose?
Do we mean low cost simple flight?
Do we mean zero gravity?
Do we me low cost simple space flight? *Interplanetary? *Interstellar?
Do we mean simple low cost escape from Earth?
Do we mean warp drive?

2,4 and 5 are in principle possible. I don't know what you mean by "3"
as zero g is a natural concomitant of all space flight. If we have a
low cost way of getting to LEO we would surely describe it as that and
NOT use the term "antigravity". I have looked at the Website of
"American Antigravity" http://www.americanantigravity.com/

A large number of things are lumped toether. If air rotates round a
disc you will get lift. This is really not all that surprising when we
recall that a wing of ye bog standard fixed wing airplane has air
flowing faster over the upper surface. This is possible, could even be
a fruitful line of research, problem is how to stabalize air flows.
However it is lumped in with things that are definitely not possible.

I would like to add something here. After WW2 the Americans were on
the look out for Nazi scientists. There was the order of the Balack
Sun

http://sungaya.de/schwarz/allmende/schwarzesonne.htm
http://naziufomythos.greyfalcon.us/discaircraft.html
http://greyfalcon.us/BACKUP.htm

The truth of the matter is that the Coanda effect was known for yonks.
The Nazi flying saucers are again a mixture of feasiblity and hype.
Subsonic verical take off discs were constructed and worked. Their
performance though was inferior to that of the helicopter. They were
also chronically unstable.

The fact of the matter is that the CIA (as well as not having anyone
who understands the Middle East) are scientific illiterates who prefer
to consults with other people from their cloak and dagger world rather
than consult reputable scientists. In short they swallowed the "Black
Sun" whole.


All these things have been associated with the words 'anti-gravity' -
but each implies a different set of physical rules.

INERTIALESS ACCELERATION
This form of acceleration somehow overcomes inertia. *Force is applied
to a body, but no forces are felt BY the body. *The advantage of this
is that very large forces can then be applied without them being felt
by the body. *This is good for high speed maneuvering. *This is also
good for high speed interstellar travel. *At least for short ship
times. * That's because it takes about 1 year to accelerate to near
the speed of light. *A constant gee starship takes on the order of
years to cross interstellar distances, and circumnavigates the
universe in about 41 years. *Ship time. *Of course, a source of energy
large enough to maintain acceleration is needed. Increasing
acceleration to 10 gees reduces everything by a factor of 10. *An
acceleration of a million gees, allows us to travel around the
universe in minutes. *Which is pretty freaking amazing. *If we can do
it. *There are some possible approaches to achieving this;

*(1) Gravity linked bodies. *Imagine two bodies, one a very dense
pancake equipped with some sort of high energy rocket, the other a
conventional spacecraft. *The spacecraft navigates to FALL INTO the
dense pancake, but before it hits the pancake, the pancake itself
equipped with a rocket, accelerates away - so that the spacecraft
never hits. *See what's happening? *A spacecraft is being accelerated
toward an accelerating body and never reaching it. *And even though
the gravitating mass with the rocket attached feels the force, the
spacecraft falling toward the gravitating body is in free fall. *So,
if the surface gravity of the gravitating body is 100 gees, the
spacecraft would be in free fall toward it, and be accelerated through
space at 100 gees. *If the pancake accelerated at 99 gees, the and the
spacecraft sat on the surface of the pancake - the occupants would
feel a 1 gee force even though they were be accelerated at 99 gees in
the opposite direction. *It would take 3 days to approach light speed
like this, and less than 5 months to circumnavigate the universe if
energy weren't a problem.

I believe negative mass to be impossible (as is FTL). Why is negative
mass and FTL linked? In the beginning 13.7 billion years ago there was
indeed negative mass. This produced "Inflation". Now Inflation is
really a warp and the expansion occured FTL.

The fact of the matter is that a negative mass cannot be constrained
to be attached to a positive mass and travel at below the speed of
light. The fact is it would produce a warp and travel FTL, although
FTL really refers to warp and event horizons. It is the SPACE that is
moving. I think this should be pondered. Negative mass is something
that should be approached with extreme caution. I don't believe it can
be produced, but if it could be we still could not circumvent the FTL
paradoxes.

BTW - COBE/WMAP has shown the Universe not to be of circular topology.
If you trvalled at c you could traverse the Universe in 5 months of
your time. The Universe though would still be ageing at its normal
rate.

(2) Accelerating all atoms equally. *Highly penetrating - but non-
destructive radiation - like neutrino flux, accelerates all atoms
equally that a neutrino beam passes through. *There would be little or
no body forces using this system. *The amounts of energy would be
tremendous

(3) Reduction of inertia. *Some believe that inertial mass and
gravitational mass are linked by the flux of virtual particles in the
vacuum. *That is, a flux of virtual photons rain down around every
particle in existence, and the gravitational effects interact with
these virtual photons to exert a radiation pressure that is felt as
inertia. *Unruh showed that this would create a body force only when
particles were accelerated through the vacuum.

http://en.wikipedia.org/wiki/Unruh_effect

Elementary particle phics will not help us. The mass of particles is
very much a bootstrap effect. Interactions cause mass.

Somehow eliminating or reducing or engineering this effect to decouple
inertial and gravitational mass could do some amazing things. *One of
these is to switch off inertial mass and accelerate something with
very little energy to light speed. * Then switch on the inertial mass
again to slow it down. *This would violate today's laws of physics,
primarily by creating a huge imbalance between kinetic and potential
energies. *This however can be considered a way of tapping the vacuum
energy - if it existed.

LOW COST SIMPLE FLIGHT
All the methods described above appear to be very difficult and energy
intensive and are not conducive to low cost access to space. *Low cost
simple flight is rather simple and does not contribute to
spaceflight.

(1) electric propulsion. *Nitrogen in air is diamagnetic. *Electrical
and magnetic effects might be used to move air directly without
rockets or wings or rotos or jets.

Better to use a plasma.

(2) MEMs based rocket array. *Micro-electromechanical systems have
been built that spray rocket fuels around the way ink jet printers
spray ink around. *These rocket fuels power very tiny rocket engines.
Millions of rocket engines can be made to operate together, to create
a wide range of propulsive effects, and in fact create a propulsive
skin around an aircraft. *Due to their small size and high frequency
of operation, the process is likely to be very quiet. *Due to the
ability to operate together, they can even be made to actively cancel
each other's irreducible noise. *Due to their high thrust to weight,
performance is likely to be awesome. *Due to their large number, and
small size, safety and reliability is likely to be unparalleled.
Control surfaces are likely not needed either, as there are thousands
of rockets likely pointed in the diirection needed to create whatever
propulsive effect is needed.

This is an interesting one. The only idea which could be feasible. In
fact a hypersonic aircraft is going to work on a very similar
principle. The airflow iself produces thrust. If you were to use
nanotechnology and reduce turbulence kinetic heating would be reduced.
One miight also be able to reduce turbulence inside a rocket and
achieve a rocket with long maintainance schedules.

ZERO GRAVITY
Putting a large massive object on a set of columns has the potential
to reduce the gravity forces immediately beneath it.

LOW COST SIMPLE SPACE FLIGHT
A gravity boost has been achieved in interplanetary flight by flying
by Jupiter at high speed. *The spacecraft is in free fall and falls
toward jupiter and away from jupiter at the same speeds. *But not in
the same direction. *If jupiter were static it would be like bouncing
a ball off the wall. *But jupiter is moving relative to the sun. *So,
this is like bouncing a ball off of a baseball bat being swung by Babe
Ruth! *Even though the ball bounces of the bat like it bounced off the
wall, the moving bat imparts energy to it relative to the baseball
diamond. *Same with jupiter and the spacecraft.

Now imagine two massive objects in tight orbit around each other. *You
could drop a 'ball' or space craft into this system, and it would
fling the object out along any trajectory in the plane of rotation.
Just be careful when and where you enter the system. *If the objects
are orbiting one another at near light speed - the objects can be
accelerated to near light speed very quickly. *A similar set of
objects at the target point, could reverse the process and remove all
the energy from the spacecraft. *Only slight rocket blasts would be
needed for course correction and entering the target at precisely the
right time and direction.

The cool part here is that the energy in the spacecraft would be
stored in the receiving bodies - and then be available to sent the
spacecraft back from whence it came. *Ship board times could be
minutes if speeds were high enough. *Spacecraft could be very simple.
In fact a man or woman in a spacesuit, with a rocket pack and radio
transmitter/receiver would be able to use two pairs of orbiting bodies
to fly back and forth across interstellar distances very simply - and
they would be in free fall the whole way.

You would need far more energy to manoever the other bodies.



- Ian Parker