The "force" of gravity? Please explain.
Ken Fischer
mj1...@janus.swipnet.se wrote:
: kfis...@iglou.com (Ken Fischer) wrote:
: >mj1...@janus.swipnet.se wrote:
: >: Personally I don't think expansion theories can explain gravity. Among
: >: other things it seems to be hard to get the 1/r^2 dependance.
: >
: > The inverse square function of the external field in
: >Divergent Matter results because bodies of matter double in
: >size in certain periods of time.
: If we call the doubling time T for a body with diameter 1m and mass
: 1kg, and look at three such bodies:
:
: o -10m- o -20m- o
:
: at t=0
:
: then at t=T
: the bodies now have diameter 2m
:
: O -9m- O -19m- O
:
: we can continue this and conclude: the attraction of two bodies of the
: same size and mass is independent of the distance between them.
I don't believe you have interpreted DM correctly here,
it looks to me like you are using time units of the same length,
if matter expands, all clocks must slow with time, giving the
equivalent of 1,2,4,8..... as the lengthening series of T units,
so you need to look at more T units to make thought experiment
function properly.
Also, you have objects not having a motion of translation,
which is more of a difficult thing to accomplish than first appears.
You must consider how the objects got to where they are,
and the motion of translation of the centers of mass. I am not
objecting to having zero motion of translation of the COMs, but
it is something that must be considered, because as the meter
stick lengthens (matter, all objects, are meter sticks), the
"space" between objects _decreases_ UNLESS objects are moving
apart.
This is difficult to imagine unless a "fixed" meter
stick is used, the length being -the-length-that-it-was-at-
t = 0 (this _is_ a thought experiment), so this is possible.
If done properly, I think you will see results
essentially equal to Newtonian gravitation (I sure hope). :-)
: >: Field theories on the other hand could very well be the answer to
: >: gravity.
: >
: > I think "field" theories refer to the mathematics,
: >rather than the mode of operation. In Divergent Matter,
: >matter is one field, and everything around matter is the
: >other.
: Yes, that might be true. When I talk about field theories I mean
: theories with the same structure as QED.
I don't understand why you have a preference for
what form a theory takes, "quantum" merely means numbers
or how many, expressed in integer units.
If you mean that you prefer a model of gravitation
that somehow reaches out, grabs distant things, and pulls
on them, I think that is what Newtonian gravitation is.
For this, you need magic, or a totally new means
of interaction at a distance that we are not aware of,
which I would not object to, if everybody would consider
Divergent Matter until the means of magic is discovered.
: > The attractive thing about Divergent Matter is that
: >the external field is purely geometrical, needing no method
: >of operation. The fact that the units of time and length
: >do lengthen with the passage of time makes Divergent Matter
: >the only model of gravitation and TOE that ties space and
: >time together based on a physical cause.
:
: but space doesn't expand in your theory...
The distance of separation (if that is what you mean
by "space") does expand if you do the thought experiment
properly, or else things would appear to real world observers
to have a velocity towards each other. The thought experiment
must establish whether or not there is an actual motion toward
each other or not, or if there is a motion away from each other
or not.
In complex geometry models, which General Relativity and
Divergent Matter are, the prior history of the motion of an
object is the important thing, rather than the position relative
to a background "space".
So, in Divergent Matter, "space" does expand, even though
space has no intrinsic properties or attributes, that is why and
how ""coordinate free" theories have to work.
: > (Assuming the above should read "If we developed") I have
: >to say that space-time curving is observed, and Newton got
: >around that by using a "field" theory, and it works great,
: >but it leaves too much out, and isn't as accurate as General
: >Relativity, and let's face it, General Relativity is a
: >mathematical "field" theory, it just uses complex geometry.
: GR claims to explain the real world, with curving of space-time.
: GR is more accurate, but I see no reason why a field theory couldn't
: be modified to incorporate that accuracy. GR has limiations that would
: be nice to get around. And I think the premisses of GR can be
: interpretated in other ways.
I agree that there may be things about General Relativity
that may have been misinterpreted, or things added on that don't
belong there.
But I repeat, why have a preference for the form a theory
takes, it must describe nature, and if there is nothing in nature
that can reach out from every object and grab every other object
in the universe at the same time and pull on all of them at the
same time, then we might have to settle for Divergent Matter,
whether it is attractive to us or not.
: > That is an excellent description of Newtonian Gravitation,
: >which will be used for most calculations where gravitation is
: >concerned, probably forever, and General Relativity will be
: >used when high accuracy is needed and for very high speeds
: >and near dense bodies of matter.
: The premise of GR is that you can't know the difference between
: acceleration and gravity. That doesn't mean that they are the same. If
: you by the same premisses could develop a quantum field theory for
: gravity, the same effects would be incorporated and big problems could
: be avoided.
It doesn't mean they _are_ the same, but it also doesn't
mean they -can't-be- the same. Please point out the big
problems, and I will be glad to consider whether or not to
try to explain them.
: > The advantage of having a model of gravitation
: >that produces a totally different result than existing
: >"attractive" theories is the ability to compare models
: >with each other and with observation.
: I agree. But your theory needs more development and a mathematical
: structure to be able to explain phenomena already observed.
In "down to Earth" situations, yes, but in astrophysics,
merely being aware that a model of gravitation based on matter
expanding, is enough to allow evaluation of processes taking
place, and to compare the different models.
In star formation, heating would inhibit aggregation,
while in Divergent Matter, heating would enhance aggregation,
and produce more heating at the interface between different
density regions.
This becomes even more interesting because hydrogen
can appear to be invisible in visible light according to
what the temperature is, and whether it is illuminated by
it's own temperature or other radiant sources.
: > Most stars are formed with less than 5 times
: >the mass of the sun.
:
: I am sure that this can be explained using attractive theories
: (although I don't know how, I'm no expert in astrophysics)
: Mathias Ljungberg
As computers get more powerful, we will find out,
there is still not nearly enough computing power to properly
consider the models already being considered.
But from what has been studied, an attractive model
like Newtonian gravitation does not work at all.
If astrophysicists simple watch for signs of outward
moving processes, and the heating zones, that would tell them
whether or not Divergent Matter needs to be studied more closely.
Thank you for the message,
Kenneth Edmund Fischer - Inventor of Stealth Shapes - U.S. Pat. 5,488,372
Divergent Matter GUT of Gravitation http://www.iglou.com/members/kfischer
mj1...@janus.swipnet.se
kfis...@iglou.com (Ken Fischer) wrote:
>: If we call the doubling time T for a body with diameter 1m and mass
>: 1kg, and look at three such bodies:
>:
>: o -10m- o -20m- o
>:
>: at t=0
>:
>: then at t=T
>: the bodies now have diameter 2m
>:
>: O -9m- O -19m- O
>:
>: we can continue this and conclude: the attraction of two bodies of the
>: same size and mass is independent of the distance between them.
> I don't believe you have interpreted DM correctly here,
>it looks to me like you are using time units of the same length,
>if matter expands, all clocks must slow with time, giving the
>equivalent of 1,2,4,8..... as the lengthening series of T units,
>so you need to look at more T units to make thought experiment
>function properly.
I really don't see how this would affect the discussion. If time slows
down, there would still be equivalence in the relations of the bodies.
T aT d1 r1 d2 r2 d3
0 0 1 10 1 20 1
1 1 2 9 2 19 2
2 2 4 7 4 17 4
3 4 8 3 8 13 8
4 8 16 (-5) 16 5 16
T= slowed time
aT= "absotute" time
d1,d2,d3= diameters of the bodies
r1,r2= distances between bodies
Of course the (T=4) line doesn't agree with DM, but it is unimportant.
> Also, you have objects not having a motion of translation,
>which is more of a difficult thing to accomplish than first appears.
> You must consider how the objects got to where they are,
With these small bodies, we could simply try it in a space station in
orbit. We would just fix them to a iron bar (so there is no
mass-centre velocity in our frame, the "absolute" velocity can be
calculated using the doubling time for the bar) and drop them in
space.
>and the motion of translation of the centers of mass. I am not
>objecting to having zero motion of translation of the COMs, but
>it is something that must be considered, because as the meter
>stick lengthens (matter, all objects, are meter sticks), the
>"space" between objects _decreases_ UNLESS objects are moving
>apart.
> This is difficult to imagine unless a "fixed" meter
>stick is used, the length being -the-length-that-it-was-at-
>t = 0 (this _is_ a thought experiment), so this is possible.
What's the problem? The meter stick also expands at the same rate as
the bodies. We therefore know the size of a meter at any point in time
(if we know T)
> If done properly, I think you will see results
>essentially equal to Newtonian gravitation (I sure hope). :-)
Still you are unable to explain the dependance of distance (or mass,
for that matter).
> I don't understand why you have a preference for
>what form a theory takes, "quantum" merely means numbers
>or how many, expressed in integer units.
> If you mean that you prefer a model of gravitation
>that somehow reaches out, grabs distant things, and pulls
>on them, I think that is what Newtonian gravitation is.
> For this, you need magic, or a totally new means
>of interaction at a distance that we are not aware of,
>which I would not object to, if everybody would consider
>Divergent Matter until the means of magic is discovered.
Well, how come that EM is explained by the exchange of
photons (in QED)? Magic? OK, since it is based on QM I might agree,
but it can explain all known observations. GR can't, for example in
the very small scale and very strong gravity (black holes). This would
require a theory for quantum gravitation (in order not to violate QM
laws), but the two theories are incompatible. A theory is an attempt
to explain reality, and when it fails, alternative theories must be
considered. I think a theory of gravitation along the lines of QED
would be able to explain these phenomena (QM has never failed to
do so), and make it possible to combine all theories to one.
Sure we will consider your theory (and try to find faults in it), as
well as every other theory.
>: but space doesn't expand in your theory...
>
> The distance of separation (if that is what you mean
>by "space") does expand if you do the thought experiment
>properly, or else things would appear to real world observers
>to have a velocity towards each other.
Oh, they do, it's called gravity. :-)
> The thought experiment
>must establish whether or not there is an actual motion toward
>each other or not, or if there is a motion away from each other
>or not.
Can be easiely done as explained above.
> In complex geometry models, which General Relativity and
>Divergent Matter are, the prior history of the motion of an
>object is the important thing, rather than the position relative
>to a background "space".
> So, in Divergent Matter, "space" does expand, even though
>space has no intrinsic properties or attributes, that is why and
>how ""coordinate free" theories have to work.
I think you mean that space expands if two objects move away from each
other. But the galaxies are accelerating away from each other because
the space between them expand, the galaxies aren't accelerating.
> I agree that there may be things about General Relativity
>that may have been misinterpreted, or things added on that don't
>belong there.
> But I repeat, why have a preference for the form a theory
>takes, it must describe nature, and if there is nothing in nature
>that can reach out from every object and grab every other object
>in the universe at the same time and pull on all of them at the
>same time, then we might have to settle for Divergent Matter,
>whether it is attractive to us or not.
Sure, I will settle for any theory that explains reality. However
there are often interpretations within the theory itself, like in QM.
I think everybody accepts that QM describes reality, but very few
accept the current interpretations.
> It doesn't mean they _are_ the same, but it also doesn't
>mean they -can't-be- the same. Please point out the big
>problems, and I will be glad to consider whether or not to
>try to explain them.
Big problems:
1. GR and QM are incompatible
2. GR fails to explain reality at microscopic levels, and at high
energies.
Other reasons:
1. Since the forces are so similar, it would be nice to have a common
structure, so a TOE could be obtained.
2. The principle of equivalence doesn't automaticly lead to GR, it
could as well be interpretated in a different way.
3. If GR was proved wrong, SR would still be valid.
> In "down to Earth" situations, yes, but in astrophysics,
>merely being aware that a model of gravitation based on matter
>expanding, is enough to allow evaluation of processes taking
>place, and to compare the different models.
Perhaps, but it still is necessary to be able to explain all known
phenomena.
> This becomes even more interesting because hydrogen
>can appear to be invisible in visible light according to
>what the temperature is, and whether it is illuminated by
>it's own temperature or other radiant sources.
What do you think is the reason for this?
Mathias Ljungberg
Ken Fischer
mj1...@janus.swipnet.se wrote:
: kfis...@iglou.com (Ken Fischer) wrote:
: >: If we call the doubling time T for a body with diameter 1m and mass
: >: 1kg, and look at three such bodies:
: >:
: >: o -10m- o -20m- o
: >:
: >: at t=0
: >:
: >: then at t=T
: >: the bodies now have diameter 2m
: >:
: >: O -9m- O -19m- O
online, and need to explain further;
Even though everthing has to double in size in the
same period of time in order to keep relative size, the
expansion that causes the doubling in size has two components,
an acceleration as a function of density, and a residual
outward velocity of the surface of each object.
: >: we can continue this and conclude: the attraction of two bodies of
: >: same size and mass is independent of the distance between them.
The fact that they have doubled in size does not
tell us what part was due to acceleration, and what part
was due to residual velocity of the surfaces.
With expanding matter, T_0 must be reserved for the
instant of the Big Bang, or essentially zero size, and there
was a very large number of doubling times to get to the present
time and size.
The outward residual velocity must be included in any
thought experiment, and the acceleration of the surface merely
increases the velocity and produces the phenomenon of surface
gravity.
: > I don't believe you have interpreted DM correctly here,
: >it looks to me like you are using time units of the same length,
: >if matter expands, all clocks must slow with time, giving the
: >equivalent of 1,2,4,8..... as the lengthening series of T units,
: >so you need to look at more T units to make thought experiment
: >function properly.
: I really don't see how this would affect the discussion. If time slows
: down, there would still be equivalence in the relations of the bodies.
The slowing of time allows moving objects to move
a greater _actual_ distance in each _actual_ unit of time and
this affects the existing velocities.
Objects placed in space that appear to us to be
stationary, actually are movng apart.
: > Also, you have objects not having a motion of translation,
: >which is more of a difficult thing to accomplish than first appears.
: > You must consider how the objects got to where they are,
: With these small bodies, we could simply try it in a space station in
: orbit. We would just fix them to a iron bar (so there is no
: mass-centre velocity in our frame, the "absolute" velocity can be
: calculated using the doubling time for the bar) and drop them in
: space.
The ends of the bar would be moving apart as the
bar expands, according to the density of the bar.
A higher density bar would have the ends moving
apart with less velocity, but with a greater acceleration.
I am sorry I can't describe this in a way to make
it easier to understand. I am trying to prepare a better
presentation to put in my homepage, but it is difficult
because it has to result in the curvature of spacetime
that we observe.
: >and the motion of translation of the centers of mass. I am not
: >objecting to having zero motion of translation of the COMs, but
: >it is something that must be considered, because as the meter
: >stick lengthens (matter, all objects, are meter sticks), the
: >"space" between objects _decreases_ UNLESS objects are moving
: >apart.
: > This is difficult to imagine unless a "fixed" meter
: >stick is used, the length being -the-length-that-it-was-at-
: >t = 0 (this _is_ a thought experiment), so this is possible.
: What's the problem? The meter stick also expands at the same rate as
: the bodies. We therefore know the size of a meter at any point in time
: (if we know T)
It depends on the density of the meter stick, and
in order to see the underlying motions, the moving objects
must move in front of a background grid made of t = 0
meter sticks. There are no coordinates, and the only
thing to relate motion and position to is prior motion,
position and size.
: > If done properly, I think you will see results
: >essentially equal to Newtonian gravitation (I sure hope). :-)
: Still you are unable to explain the dependance of distance (or mass,
: for that matter).
I thought I had, in the old description on my
homepage, and in the section titled "Kinematics".
Obviously I will have to try to do better.
: > I don't understand why you have a preference for
: >what form a theory takes, "quantum" merely means numbers
: >or how many, expressed in integer units.
: > If you mean that you prefer a model of gravitation
: >that somehow reaches out, grabs distant things, and pulls
: >on them, I think that is what Newtonian gravitation is.
: > For this, you need magic, or a totally new means
: >of interaction at a distance that we are not aware of,
: >which I would not object to, if everybody would consider
: >Divergent Matter until the means of magic is discovered.
: Well, how come that EM is explained by the exchange of
: photons (in QED)? Magic?
From what little I know, I think it is very
short range and they are virtual photons invented to
provide a working model.
Magnetism is somewhat the same, falling off
very rapidly with distance.
: OK, since it is based on QM I might agree,
: but it can explain all known observations. GR can't, for example in
: the very small scale and very strong gravity (black holes). This would
: require a theory for quantum gravitation (in order not to violate QM
: laws), but the two theories are incompatible. A theory is an attempt
: to explain reality, and when it fails, alternative theories must be
: considered. I think a theory of gravitation along the lines of QED
: would be able to explain these phenomena (QM has never failed to
: do so), and make it possible to combine all theories to one.
: Sure we will consider your theory (and try to find faults in it), as
: well as every other theory.
DM is a quantum theory, each particle of a given
type expands a given amount, and these little expansions
are additive, producing a big expansion for big objects.
The model must create itself, and this is different
from most theories that have multiple postulates, all I
can do is try to understand it and explain it, I can't
change it, it exists on it's own, and on it's own merits.
: >: but space doesn't expand in your theory...
: >
: > The distance of separation (if that is what you mean
: >by "space") does expand if you do the thought experiment
: >properly, or else things would appear to real world observers
: >to have a velocity towards each other.
: Oh, they do, it's called gravity. :-)
My favorite subject. :-)
: > The thought experiment
: >must establish whether or not there is an actual motion toward
: >each other or not, or if there is a motion away from each other
: >or not.
: Can be easiely done as explained above.
No, it is very difficult to explain, and even
more so for small objects the same size.
It is easier to consider a test object above
the surface of the Earth, like a rocket.
The surface of the Earth has an upward velocity,
and the rocket accelerates to a higher velocity, then
coasts.
In DM it stays in motion and the surface of the
Earth catches up to it, but in Newtonian gravitation,
it is slowed by gravity, stops, and falls.
This thought experiment is easier to understand
and is something we know well, we just are biased by
being taught universal attraction, and we don't see
the true motion of the rocket.
If we know that gravity does not slow the
rocket, then we know what we have to do to understand
how gravity really works, without the attractive "force".
: > In complex geometry models, which General Relativity and
: >Divergent Matter are, the prior history of the motion of an
: >object is the important thing, rather than the position relative
: >to a background "space".
: > So, in Divergent Matter, "space" does expand, even though
: >space has no intrinsic properties or attributes, that is why and
: >how ""coordinate free" theories have to work.
:
: I think you mean that space expands if two objects move away from each
: other. But the galaxies are accelerating away from each other because
: the space between them expand, the galaxies aren't accelerating.
I don't think galaxies appear to be accelerating
apart, I think they are in inertial motion, with the more
distant ones moving with higher velocity.
I don't consider space to have any intrinsic
attributes, it can't expand because space doesn't have any
size or length. But let's not consider cosmology until
we can agree on the simple freefall thought experiment
that shows the actual motions that we misinterpret.
: > I agree that there may be things about General Relativity
: >that may have been misinterpreted, or things added on that don't
: >belong there.
: > But I repeat, why have a preference for the form a theory
: >takes, it must describe nature, and if there is nothing in nature
: >that can reach out from every object and grab every other object
: >in the universe at the same time and pull on all of them at the
: >same time, then we might have to settle for Divergent Matter,
: >whether it is attractive to us or not.
:
: Sure, I will settle for any theory that explains reality. However
: there are often interpretations within the theory itself, like in QM.
: I think everybody accepts that QM describes reality, but very few
: accept the current interpretations.
For what it is, QM works well, and DM does not
contradict it, in fact, I think DM is Quantum Gravity,
it just isn't what most people expect, they expected
some magical gravitons to reach out and pull things
at a distance.
: > It doesn't mean they _are_ the same, but it also doesn't
: >mean they -can't-be- the same. Please point out the big
: >problems, and I will be glad to consider whether or not to
: >try to explain them.
: Big problems:
: 1. GR and QM are incompatible
: 2. GR fails to explain reality at microscopic levels, and at high
: energies.
I wasn't aware that General Relativity had
any big problems. There is no reason to think that
GR has to be compatible, it would just be nice if it
were.
But I think GR is compatible with DM, and I
think DM is Quantum Gravity.
: Other reasons:
: 1. Since the forces are so similar, it would be nice to have a common
: structure, so a TOE could be obtained.
Perhaps DM is the TOE, it just has to be studied.
There are no forces acting at a distance in gravity, in
my opinion, that is just the way we were taught.
: 2. The principle of equivalence doesn't automaticly lead to GR, it
: could as well be interpretated in a different way.
DM takes the POE literally, and I think GR
is a direct result of Einstein's Principle of Equivalence,
except he wrote it in terms of how we observe and measure.
DM has to be seen as the underlying kinematics
of GR and spacetime. Does any other theory require
that time be dependent on the length of the meter stick?
: 3. If GR was proved wrong, SR would still be valid.
I do not consider Special Relativity to exist
separate from General Relativity.
: > In "down to Earth" situations, yes, but in astrophysics,
: >merely being aware that a model of gravitation based on matter
: >expanding, is enough to allow evaluation of processes taking
: >place, and to compare the different models.
: Perhaps, but it still is necessary to be able to explain all known
: phenomena.
I feel that DM has a better chance of doing
that, while I don't know of another theory that has any
chance of doing it.
Gravity and inertial motion and the elementary
particles are all connected, and energy is intimately
connected too. I will try to write better descriptions
of each individual thought experiment for my homepage,
and I hope others will try to understand how DM works,
it is just universal repulsion. :-)
mj1...@janus.swipnet.se
kfis...@iglou.com (Ken Fischer) wrote:
> The fact that they have doubled in size does not
>tell us what part was due to acceleration, and what part
>was due to residual velocity of the surfaces.
We don't need to know the components. In the thought experiment, we
don't even need to know T, it just states: given that every object has
a doubling time (that must be the same for all objects), the
attraction is independent of distance (and furtermore, mass).
>The slowing of time allows moving objects to move
>a greater _actual_ distance in each _actual_ unit of time and
>this affects the existing velocities.
> Objects placed in space that appear to us to be
>stationary, actually are movng apart.
We can find out enough by using relative measurements.
> It depends on the density of the meter stick, and
>in order to see the underlying motions, the moving objects
>must move in front of a background grid made of t = 0
>meter sticks. There are no coordinates, and the only
>thing to relate motion and position to is prior motion,
>position and size.
It doesn't matter what the outward velocity and acceleration
are, as long as we know the doubling time. A meter stick will always
be proportional to other objects. A meter is allways a meter.
>: Well, how come that EM is explained by the exchange of
>: photons (in QED)? Magic?
> From what little I know, I think it is very
>short range and they are virtual photons invented to
>provide a working model.
> Magnetism is somewhat the same, falling off
>very rapidly with distance.
Wrong, the electrical force is unlimited and is proportional to 1/r^2.
Magnetism is proportional to 1/r, and it is thus stronger much
stronger in distance than the electrical force (ever wondered how you
can watch TV ?).
> No, it is very difficult to explain, and even
>more so for small objects the same size.
I understand what you mean. But I think the whole concept of a
doubling time must be wrong, it is therefore meaningless to discuss
the components of it.
> I don't think galaxies appear to be accelerating
>apart, I think they are in inertial motion, with the more
>distant ones moving with higher velocity.
Yes, I was wrong, they don't accelerate. But sometimes they can have
greater velocities than light. This would be impossible if the space
between the didn't expand (SR).
> : Big problems:
>: 1. GR and QM are incompatible
>: 2. GR fails to explain reality at microscopic levels, and at high
>: energies.
> I wasn't aware that General Relativity had
>any big problems. There is no reason to think that
>GR has to be compatible, it would just be nice if it
>were.
In microscopic levels some kind of quantisation is necessary, or else
it would be possible to get around certain QM limitations. The fact
that QM can't be applied on GR, suggests that one of them (or both) is
wrong (or at least not fundamental). To be able to explain these
phenomena we must in someway unite the two theories. The super string
theory is an attempt to do that, but since it must create both QM and
GR theories in approximation, it is extremly complicated. If we could
create a QG theory in QM form, we would have no immediate need for a
single theory although it would be much easier to obtain than trying
to unite GR and QM.
>: Other reasons:
>: 1. Since the forces are so similar, it would be nice to have a common
>: structure, so a TOE could be obtained.
> Perhaps DM is the TOE, it just has to be studied.
>There are no forces acting at a distance in gravity, in
>my opinion, that is just the way we were taught.
So where are your expansion theories for the other forces?
>: 2. The principle of equivalence doesn't automaticly lead to GR, it
>: could as well be interpretated in a different way.
>: 3. If GR was proved wrong, SR would still be valid.
> I do not consider Special Relativity to exist
>separate from General Relativity.
They are two separate theories. SR describes relativety at constant
velocities. GR describes accelerated and rotational motion (that is
really a generalisation of SR), but it also states that space-time is
(or rather can be) curved in a way that explains gravity. That second
part, that space-time is curved, isn't necessary for everything else
to work. It is possible to have a flat space-time with forces to
explain gravity.
Mathias Ljungberg
Ken Fischer
: >was due to residual velocity of the surfaces.
: We don't need to know the components. In the thought experiment, we
: don't even need to know T, it just states: given that every object has
: a doubling time (that must be the same for all objects), the
: attraction is independent of distance (and furtermore, mass).
Both of your assumptions are incorrect. After
an astronomy class in 1958 I was told by the professor
that the density of the Earth was much greater in the
core and that the peak acceleration of gravity was well
below the surface (he had 20 years experience working
with geologists the big gravimeter project, I was lucky
to be in his class else I might have never known this).
The surface gravity of a planet in DM has to
be about equal to mass because the expansion of each
atom is a function of two components, acceleration of
the surface, and velocity of the surface (where there
is acceleration, there is velocity).
I am sure my homepage states that the velocity
cannot exceed the radius in a unit of time, times a
constant, and for the Earth that may mean something
close to the escape velocity (11.2 km/sec), I am not sure.
Because of the effect of the lengthening units
of all dimensions, the resulting spacetime is very much
governed by the relative velocities of the centers of
mass of all objects.
The expansion of a balloon of lightweight material
certainly cannot be exactly the same as that of a sphere
of gold having the same radius, if I thought it could,
I would definitely erase my homepage.
The acceleration of gravity of the surface of the
Earth is 9.81 meters per second/per second.
The outward radial (upward) velocity of the Earth
is either the escape velocity, or a substantial fraction
of it.
Both these values are constants in current units,
the acceleration is apparent and observed, the velocity
is hidden by the lengthening units of measure (naturally
we do not "feel" velocity).
The surface gravity of the Sun is about 29 g's,
and it has an outward radial velocity of the surface
of possibly as much as a couple of million kilometers
per hour.
With this information it should be possible to
determine more accurate values for the hidden velocity
components that cauase the Earth and the Sun the same
relative size. That is what I had to do in 1958 or
else abandon the model.
So I am confident that DM predicts apparent
attraction proportional to mass, and I am confident
that the apparent attraction falls off as the inverse
square of the distance.
I wanted to be able to present an example of
this in text mode on a 24 x 80 display, but I found
it is difficult, so I am going to try to see if it
can be done on a large sheet of paper, then see if
I can convert it to the computer text mode display.
: >The slowing of time allows moving objects to move
: >a greater _actual_ distance in each _actual_ unit of time and
: >this affects the existing velocities.
: > Objects placed in space that appear to us to be
: >stationary, actually are movng apart.
: We can find out enough by using relative measurements.
No, the velocities are hidden, the lengthening
meter stick keeps pace with the velocities, which even
means the velocities are constanly increasing in the
underlying kinematics if T_1 meter sticks are used,
but the covariance of units hides all this from us.
: > It depends on the density of the meter stick, and
: >in order to see the underlying motions, the moving objects
: >must move in front of a background grid made of t = 0
: >meter sticks. There are no coordinates, and the only
: >thing to relate motion and position to is prior motion,
: >position and size.
: It doesn't matter what the outward velocity and acceleration
: are, as long as we know the doubling time. A meter stick will always
: be proportional to other objects. A meter is allways a meter.
In the observable world at constant temperature,
yes, but obviously we don't see or measure the hidden
velocities.
The only way to "see" the real kinematics is to
use a background grid of T_1 meter sticks during thought
experiments, or else we will see exactly what we observe.
To study the kinematics we need to be able to
see the _actual_ T_1 velocities.
: >: Well, how come that EM is explained by the exchange of
: >: photons (in QED)? Magic?
: > From what little I know, I think it is very
: >short range and they are virtual photons invented to
: >provide a working model.
: > Magnetism is somewhat the same, falling off
: >very rapidly with distance.
: Wrong, the electrical force is unlimited and is proportional to 1/r^2.
I am not sure what you mean, photons propagate
with an inverse square falloff, I don't know what you mean
by "electrical force".
: Magnetism is proportional to 1/r, and it is thus stronger much
: stronger in distance than the electrical force (ever wondered how you
: can watch TV ?).
Magnetism falls of as the inverse fourth power,
we seem to have such a wide difference of opinion, I do not
think we can even be talking about the same thing.
A TV picture tube uses positive rectified high
voltage to accelerate (repulse) electrons in a focused
beam within the picture tube and that beam is guided by
electromagnetic coils, but outside the picture tube I
don't find too much evidence of this except for a little
static electricity and some high frequency radio frequency
leakage.
: > No, it is very difficult to explain, and even
: >more so for small objects the same size.
: I understand what you mean. But I think the whole concept of a
: doubling time must be wrong, it is therefore meaningless to discuss
: the components of it.
The doubling time is in observed units and I think
it is required, else larger objects would not stay the same
_relative_ size.
Using only the doubling time will not provide the
underlying physics, the only reason I mention the doubling
time is to show the restraint required to have all objects
maintain relative size, I didn't mean it should be used as
part of the physics.
: > I don't think galaxies appear to be accelerating
: >apart, I think they are in inertial motion, with the more
: >distant ones moving with higher velocity.
: Yes, I was wrong, they don't accelerate. But sometimes they can have
: greater velocities than light. This would be impossible if the space
: between the didn't expand (SR).
There are no galaxies that we know of thatt recede
from us at greater speeds than the speed of light, but if
you consider that we see galaxies in opposite directions
receding at near the speed of light, then you either have
to us the Special Relativity equations for adding velocities,
or assume that even though they may be moving faster than
light away from each other, no _observations_ will result in
velocities faster than the speed of light.
: > : Big problems:
: >: 1. GR and QM are incompatible
: >: 2. GR fails to explain reality at microscopic levels, and at high
: >: energies.
: > I wasn't aware that General Relativity had
: >any big problems. There is no reason to think that
: >GR has to be compatible, it would just be nice if it
: >were.
: In microscopic levels some kind of quantisation is necessary, or else
: it would be possible to get around certain QM limitations. The fact
: that QM can't be applied on GR, suggests that one of them (or both) is
: wrong (or at least not fundamental).
Not really, Quantum optics appears to be very precise,
but that doesn't mean it has to apply to gravitons, it doesn't
even mean that gravitons have to exist.
: To be able to explain these
: phenomena we must in someway unite the two theories. The super string
: theory is an attempt to do that, but since it must create both QM and
: GR theories in approximation, it is extremly complicated. If we could
: create a QG theory in QM form, we would have no immediate need for a
: single theory although it would be much easier to obtain than trying
: to unite GR and QM.
I hope the people working on trying to unite QM and
GR will continue the effort, but I do not feel that it is
certain that it is possible, especially with gravitons.
: >: Other reasons:
: >: 1. Since the forces are so similar, it would be nice to have a common
: >: structure, so a TOE could be obtained.
: > Perhaps DM is the TOE, it just has to be studied.
: >There are no forces acting at a distance in gravity, in
: >my opinion, that is just the way we were taught.
: So where are your expansion theories for the other forces?
I have none, they work fine, and even though they
may be drastically affected by the underlying physics of
the lengthening units of measure, I don't see a problem,
in fact, I would think that DM underlying physics may
provide insight to other processes other than gravity.
: >: 2. The principle of equivalence doesn't automaticly lead to GR, it
: >: could as well be interpretated in a different way.
:
: >: 3. If GR was proved wrong, SR would still be valid.
: > I do not consider Special Relativity to exist
: >separate from General Relativity.
: They are two separate theories. SR describes relativety at constant
: velocities. GR describes accelerated and rotational motion (that is
: really a generalisation of SR), but it also states that space-time is
: (or rather can be) curved in a way that explains gravity. That second
: part, that space-time is curved, isn't necessary for everything else
: to work. It is possible to have a flat space-time with forces to
: explain gravity.
: Mathias Ljungberg
No, the above is not true, SR handles acceleration
just as well as GR. The only thing that SR cannot handle
is gravity.
Of course models of gravity in flat spacetime
exist, one of them is Newtonian universal mutual attraction,
and I would prefer that if I could find the mechanism that
reaches from each grain of sand in the universe, and each
atom of hydrogen and all other elements, out to all other
grains of sand and all other atoms, and pulls on them,
inversely proportional to the square of the distance and
directly proportional to the mass of each atom, I would
immediately forget DM.
I see nothing that can reach out like that,
so I have to continue to studu Divergent Matter.
Sincerely,
Ken Fischer
Bjorn Danielsson
<mj1...@janus.swipnet.se> wrote:
(snip)
> Wrong, the electrical force is unlimited and is proportional to 1/r^2.
> Magnetism is proportional to 1/r, and it is thus stronger much
> stronger in distance than the electrical force (ever wondered how you
> can watch TV ?).
Coulomb's law says 1/r^2 for the contribution of electric force
from a volume element dV containing a charge.
Biot-Savart's law says 1/r^2 for the contribution of magnetic force
from a line element ds containing a current.
A long wire containing an evenly distributed charge or an electric
current has a force proportional to 1/r.
For a dipole it falls off as 1/r^3.
(snip)
> They are two separate theories. SR describes relativety at constant
> velocities. GR describes accelerated and rotational motion (that is
> really a generalisation of SR), but it also states that space-time is
> (or rather can be) curved in a way that explains gravity. That second
> part, that space-time is curved, isn't necessary for everything else
> to work. It is possible to have a flat space-time with forces to
> explain gravity.
SR is valid only for inertial frames, but it can describe accelerated
and rotational motion without any problems, as long as you choose an
inertial frame for the observer. Proper time etc for an accelerated
object can be calculated by using inertial frames that momentarily
match the velocity of the accelerated object.
You can use SR + the equivalence principle to do simple calculations
of effects in gravitational fields (e.g. redshift). Full GR is only
needed when you have to consider curved spacetime.
--
Bjorn Danielsson <bo...@algonet.se>
http://www.algonet.se/~bonus
JeffMo
kfis...@iglou.com (Ken Fischer) wrote:
>mj1...@janus.swipnet.se wrote:
>: kfis...@iglou.com (Ken Fischer) wrote:
>: > I don't think galaxies appear to be accelerating
>: >apart, I think they are in inertial motion, with the more
>: >distant ones moving with higher velocity.
>: Yes, I was wrong, they don't accelerate. But sometimes they can have
>: greater velocities than light. This would be impossible if the space
>: between the didn't expand (SR).
> There are no galaxies that we know of thatt recede
>from us at greater speeds than the speed of light, but if
>you consider that we see galaxies in opposite directions
>receding at near the speed of light, then you either have
>to us the Special Relativity equations for adding velocities,
>or assume that even though they may be moving faster than
>light away from each other, no _observations_ will result in
>velocities faster than the speed of light.
Reading the relativity FAQ would clear this one up.
FROM THE FAQ
--------------------------------------------------------------------
updated 5-DEC-1994 by SIC; original by Scott I. Chase
Apparent Superluminal Velocity of Galaxies
A distant object can appear to travel faster than the speed of light
relative to us, provided that it has some component of motion
towards us as well as perpendicular to our line of sight. Say that on
Jan. 1 you make a position measurement of galaxy X. One
month later, you measure it again. Assuming you know its distance from
us by some independent measurement, you derive its
linear speed, and conclude that it is moving faster than the speed of
light.
What have you forgotten? Let's say that on Jan. 1, the object is D km
from us, and that between Jan. 1 and Feb. 1, the object
has moved d km closer to us. You have assumed that the light you
measured on Jan. 1 and Feb. 1 were emitted exactly one
month apart. Not so. The first light beam had further to travel, and
was actually emitted (1 + d/c) months before the second
measurement, if we measure c in km/month. The object has traveled the
given angular distance in more time than you thought.
Similarly, if the object is moving away from us, the apparent angular
velocity will be too slow, if you do not correct for this
effect, which becomes significant when the object is moving along a
line close to our line of sight.
Note that most extragalactic objects are moving away from us due to
the Hubble expansion. So for most objects, you don't get
superluminal apparent velocities. But the effect is still there, and
you need to take it into account if you want to measure
velocities by this technique.
--------------------------------------------------------------------
JeffMo
"A valid argument is not formed solely by ignorance." -JeffMo
"A valid argument is not formed solely by assertion." -JeffMo
Religion : Science :: Methamphetamine : Exercise
For email replies, remove the "dipstick." from my eddress.
It should be self-evident that I am not a dipstick. ;-)
Wayne Throop
: mj1...@janus.swipnet.se Mathias Ljungberg
: SR does not describe accelerated motion.
Yes it does.
: That is why the twin paradox
: really was a paradox until GR was published.
No, it wasn't.
These are frequent misconceptions. See
http://www.public.iastate.edu/~physics/sci.physics/faq/acceleration.html
http://www.public.iastate.edu/~physics/sci.physics/faq/twin_paradox.html
http://www.public.iastate.edu/~physics/sci.physics/faq/twin_gr.html
Purely SR treatments of accelerated motion, the twin paradox, and
even accelerated reference frames (and I emphase: *purely SR*)
can be found in these texts (among many other places):
Wheeler&Taylor's "Spacetime Physics" (1992)
Rindler's "Introduction to Special Relativity" (1982)
French's "Special Relativity" (1964)
Mould's "Basic Relativity" (1994)
--
Wayne Throop thr...@sheol.org http://sheol.org/throopw
thr...@cisco.com
Ken Fischer
: >certainly cannot be exactly the same as that of a sphere
: >of gold having the same radius, if I thought it could,
: >I would definitely erase my homepage.
: The time it takes for the balloon to become twice as big MUST be the
: same time it takes for the golden sphere to become twice as big. I am
: sure that you will agree on that!
Of course, and a puff of smoke can expand too, but
things having so little mass simply move almost entirely
as a result of velocity, not from acceleration, and it
is the acceleration that we call gravity, the doubling
is simply a secondary effect, although a very important
one.
: From there, it's easy to show that
: the attraction is independent of mass and distance.
There is no attraction, the relative accelerations
are a function of mass per unit of volume, and matter just
expands into surrounding space, essentially eating it up,
and filling it in, giving the appearance of attraction.
: The thought
: experiment is valid, and I say again: if objects have a doubling time,
: it is unimportant what the components are because together they must
: allways be the same: the doubling time.
You are thinking in 3D space, as I said before,
the thought experiment must consider the prior motion
of each object, you cannot just place something somewhere
in space and say there it is, it isn't moving.
The diagrams and charts you made for the thought
experiment had three objects of unspecified mass, supposedly
stationary, and you only considered the doubling factor,
which is secondary. Naturally, three objects of unspecified
mass can be in a thought experiment, and you can make them
do anything you want, but you are not talking about Divergent
Matter if you don't consider all of the physics.
: > The acceleration of gravity of the surface of the
: >Earth is 9.81 meters per second/per second.
: > The outward radial (upward) velocity of the Earth
: >is either the escape velocity, or a substantial fraction
: >of it.
: > Both these values are constants in current units,
: >the acceleration is apparent and observed, the velocity
: >is hidden by the lengthening units of measure (naturally
: >we do not "feel" velocity).
: These values are independent of the distance to other objects, so from
: another objects point of view, the enlargening wouldn't have the same
: effect as newton gravity.
The only effect you will see in 3D space is the
acceleration, the velocity is a hidden constant.
I suppose nobody has ever mentioned hidden constants
before, so I am sorry, that is the way the model works.
Points of view don't count, acceleration of the
surfaces away from the centers of mass does count.
And you must consider the worldline history of
all objects, if one rocket is at 1000 feet and just
beginning to fall, and a second rocket is at 2000 feet
and starting to fall, then they have different worldlines,
different hidden velocities, and will have different
geodesics.
The upper rocket obviously had to go faster to
get higher, and the difference between the hidden
velocities of the two rockets produces the vertical
component of geodesic deviation, and is mistaken
for an unexplained acceleration of the two rockets
away from each other due to gravitational gradients.
These facts are clear and fit observation,
the only question is, will anyone try to understand
that spacetime curvature has a physical cause, and
it is in the different velocities the rockets attained
before beginning to fall, not from some mystical ether
or magical graviton spectrum that we can't detect.
The two rockets are in inertial motion, they
are not accelerated, there is no attraction.
The Earth expands with an acceleration, and
people are biased observers.
: >: Wrong, the electrical force is unlimited and is proportional to 1/r^2.
: > I am not sure what you mean, photons propagate
: >with an inverse square falloff, I don't know what you mean
: >by "electrical force".
: The Coloumb force, the force between two charged particles. The
: photons are virtual, created from vacuum using the principle of
: uncertainty. The photons with lower energy can exist longer, and
: therefore reach longer. The longer from the charge, the weaker the
: photons.
I don't know of any "virtual photons" that are
used in any long range model.
: Magnetic waves are waves in the electric field.They arise when a
: charged particle accelerates. In a radio transmitter, electrons are
: forced to accelerate, and thereby create magnetic waves. What you do
: when you recieve radio or TV, is to stick an antenna up in the air.
: The electrons in the antenna are forced to accelerate with the same
: frequency as the transmitter. Then either frequency or amplitud
: modulation can be used to transfer information. TV is transmitted by
: magnetic waves! The fact that you easely can recieve a TV signal in
: spite of the fact that the transmitter can be hundreds of miles away
: proves that magnetism doesn't fall of very fast.
If TV is magnetic waves, then so is light, the only
difference between microwave photons and light photons is the
frequency.
Most TV stations put at least 5 megawatts into the
output devices to the antenna, and the effective range is
not very great.
If you are saying that gravity is em waves, sorry,
that is not possible.
: You state yourself that the doubling time is required in your theory.
: If we can show that any theory with a doubling time won't produce
: correct mass and distance dependance, your theory must be wrong
: (because it requires a doubling time). It really doesn't matter what
: the cause of that doubling time is.
It doesn't require a doubling time to work,
it produces a doubling time. Divergent Matter
operates by the accelerated expansion of objects.
A number of other people have published
the same concept, only they concentrate on the
acceleration of the surfaces away from the center
of mass.
This is what _is_ observed in 3D space,
but I have carried the concept further, pointing
out that there is a residual velocity, and that
the velocity plus the acceleration of the surfaces,
and the lengthening of the units of measure combine
to produce the spacetime curvature of General Relativity.
The fact that objects in nature maintain an
apparent constant size at standard temperature is
a fact of nature, not something I made up, and for
Divergent Matter to conform to nature, it just happens
that everything has to double in the same interval of
time, but you can't build a viable theory on just
the doubling time.
: I think that I have showed that, and nothing you have said so far has
: made me change my mind.
I'm still working on ways to present the model
to allow 3D people to understand 4D physics, I won't
give up, but it is a difficult problem, the restrictions
of Usenet text modes makes it more difficult.
: > There are no galaxies that we know of thatt recede
: >from us at greater speeds than the speed of light, but if
: >you consider that we see galaxies in opposite directions
: >receding at near the speed of light, then you either have
: >to us the Special Relativity equations for adding velocities,
: >or assume that even though they may be moving faster than
: >light away from each other, no _observations_ will result in
: >velocities faster than the speed of light.
: If we just consider relative local motion, you're right. But if space
: expands between galaxies, it would be possible to observe speeds
: faster that light. It is in fact predicted by GR, and it also predicts
: that light would reach us from such sources (despite that they're
: travelling faster than light).
The only way that space can _appear_ to expand is
if the galaxies are moving apart.
And the only thing about light that is definite,
is that nothing can ever be observed faster than it, simply
because the only way we can observe at a distanxe is by
means of "light" signals.
I think Divergent Matter suggests that light does
not move at a constant speed, but that we will always see
light at the same speed no matter how we observe it.
I really question if GR predicts all the things
people say it does.
: SR does not describe accelerated motion.
Almost everything in SR is accelerated motion,
the collisions in particle accelerators is accelerated
motion, as is the acceleration imparted to get the
particles up to speed.
: That is why the twin paradox
: really was a paradox until GR was published. The thing GR is about, is
: accelerated motion.
No, the thing about GR is gravity, and how matter
affects spacetime.
: Since accelerated motion can't be distinguished
: from gravitation, the theory also predicts that space-time can be
: curved in a way that produces gravity.
The only thing that curves spacetime is gravity,
SR does not deal in curved spacetime.
: That GR explains both gravity
: and acceleration is a bit unfortunate, because we can't reject GRs
: gravitation without at the same time rejecting its explanation of
: acceleration. And SR alone is not a complete theory.
You keep mentioning that GR is needed for acceleration,
it is not. I agree SR alone is not a complete theory,
: > Of course models of gravity in flat spacetime
: >exist, one of them is Newtonian universal mutual attraction,
: >and I would prefer that if I could find the mechanism that
: >reaches from each grain of sand in the universe, and each
: >atom of hydrogen and all other elements, out to all other
: >grains of sand and all other atoms, and pulls on them,
: >inversely proportional to the square of the distance and
: >directly proportional to the mass of each atom, I would
: >immediately forget DM.
: > I see nothing that can reach out like that,
: >so I have to continue to study Divergent Matter.
: Take another look at QED. In it, photons do just that (of course they
: only affect charged particles, but the principle is the same)
: Mathias Ljungberg
Photons don't "pull" at large distances. If they
did, you could apply pulsating DC to an antenna, and it
would either push things or pull them depending on the
polarity.
If that works, great, it will make fantastic
things possible. But I don't think gravity works
that way. The principle of pressure differences
in air makes things move, but gravity is a completely
different process.
mj1...@janus.swipnet.se
kfis...@iglou.com (Ken Fischer) wrote:
>: We don't need to know the components. In the thought experiment, we
>: don't even need to know T, it just states: given that every object has
>: a doubling time (that must be the same for all objects), the
>: attraction is independent of distance (and furtermore, mass).
> The expansion of a balloon of lightweight material
>certainly cannot be exactly the same as that of a sphere
>of gold having the same radius, if I thought it could,
>I would definitely erase my homepage.
The time it takes for the balloon to become twice as big MUST be the
same time it takes for the golden sphere to become twice as big. I am
sure that you will agree on that! From there, it's easy to show that
the attraction is independent of mass and distance. The thought
experiment is valid, and I say again: if objects have a doubling time,
it is unimportant what the components are because together they must
allways be the same: the doubling time.
> The acceleration of gravity of the surface of the
>Earth is 9.81 meters per second/per second.
> The outward radial (upward) velocity of the Earth
>is either the escape velocity, or a substantial fraction
>of it.
> Both these values are constants in current units,
>the acceleration is apparent and observed, the velocity
>is hidden by the lengthening units of measure (naturally
>we do not "feel" velocity).
These values are independent of the distance to other objects, so from
another objects point of view, the enlargening wouldn't have the same
effect as newton gravity.
>: Wrong, the electrical force is unlimited and is proportional to 1/r^2.
> I am not sure what you mean, photons propagate
>with an inverse square falloff, I don't know what you mean
>by "electrical force".
The Coloumb force, the force between two charged particles. The
photons are virtual, created from vacuum using the principle of
uncertainty. The photons with lower energy can exist longer, and
therefore reach longer. The longer from the charge, the weaker the
photons.
>: Magnetism is proportional to 1/r, and it is thus stronger much
>: stronger in distance than the electrical force (ever wondered how you
>: can watch TV ?).
> Magnetism falls of as the inverse fourth power,
>we seem to have such a wide difference of opinion, I do not
>think we can even be talking about the same thing.
> A TV picture tube uses positive rectified high
>voltage to accelerate (repulse) electrons in a focused
>beam within the picture tube and that beam is guided by
>electromagnetic coils, but outside the picture tube I
>don't find too much evidence of this except for a little
>static electricity and some high frequency radio frequency
>leakage.
Magnetic waves are waves in the electric field.They arise when a
charged particle accelerates. In a radio transmitter, electrons are
forced to accelerate, and thereby create magnetic waves. What you do
when you recieve radio or TV, is to stick an antenna up in the air.
The electrons in the antenna are forced to accelerate with the same
frequency as the transmitter. Then either frequency or amplitud
modulation can be used to transfer information. TV is transmitted by
magnetic waves! The fact that you easely can recieve a TV signal in
spite of the fact that the transmitter can be hundreds of miles away
proves that magnetism doesn't fall of very fast.
The force you are talking about might be the strong nuclear force. I
think it has a 1/r^4 dependance.
>: I understand what you mean. But I think the whole concept of a
>: doubling time must be wrong, it is therefore meaningless to discuss
>: the components of it.
> The doubling time is in observed units and I think
>it is required, else larger objects would not stay the same
>_relative_ size.
> Using only the doubling time will not provide the
>underlying physics, the only reason I mention the doubling
>time is to show the restraint required to have all objects
>maintain relative size, I didn't mean it should be used as
>part of the physics.
You state yourself that the doubling time is required in your theory.
If we can show that any theory with a doubling time won't produce
correct mass and distance dependance, your theory must be wrong
(because it requires a doubling time). It really doesn't matter what
the cause of that doubling time is.
I think that I have showed that, and nothing you have said so far has
made me change my mind.
> There are no galaxies that we know of thatt recede
>from us at greater speeds than the speed of light, but if
>you consider that we see galaxies in opposite directions
>receding at near the speed of light, then you either have
>to us the Special Relativity equations for adding velocities,
>or assume that even though they may be moving faster than
>light away from each other, no _observations_ will result in
>velocities faster than the speed of light.
If we just consider relative local motion, you're right. But if space
expands between galaxies, it would be possible to observe speeds
faster that light. It is in fact predicted by GR, and it also predicts
that light would reach us from such sources (despite that they're
travelling faster than light).
>: They are two separate theories. SR describes relativety at constant
>: velocities. GR describes accelerated and rotational motion (that is
>: really a generalisation of SR), but it also states that space-time is
>: (or rather can be) curved in a way that explains gravity. That second
>: part, that space-time is curved, isn't necessary for everything else
>: to work. It is possible to have a flat space-time with forces to
>: explain gravity.
>: Mathias Ljungberg
> No, the above is not true, SR handles acceleration
>just as well as GR. The only thing that SR cannot handle
>is gravity.
SR does not describe accelerated motion. That is why the twin paradox
really was a paradox until GR was published. The thing GR is about, is
accelerated motion. Since accelerated motion can't be distinguished
from gravitation, the theory also predicts that space-time can be
curved in a way that produces gravity. That GR explains both gravity
and acceleration is a bit unfortunate, because we can't reject GRs
gravitation without at the same time rejecting its explanation of
acceleration. And SR alone is not a complete theory.
> Of course models of gravity in flat spacetime
>exist, one of them is Newtonian universal mutual attraction,
>and I would prefer that if I could find the mechanism that
>reaches from each grain of sand in the universe, and each
>atom of hydrogen and all other elements, out to all other
>grains of sand and all other atoms, and pulls on them,
>inversely proportional to the square of the distance and
>directly proportional to the mass of each atom, I would
>immediately forget DM.
> I see nothing that can reach out like that,
>so I have to continue to studu Divergent Matter.
Take another look at QED. In it, photons do just that (of course they
Ken Fischer
: >from us at greater speeds than the speed of light, but if
: >you consider that we see galaxies in opposite directions
: >receding at near the speed of light, then you either have
: >to us the Special Relativity equations for adding velocities,
: >or assume that even though they may be moving faster than
: >light away from each other, no _observations_ will result in
: >velocities faster than the speed of light.
: Reading the relativity FAQ would clear this one up.
Reading the relativity FAQ will tell me the author's
opinion. There does appear to be a problem;
: FROM THE FAQ
: --------------------------------------------------------------------
: updated 5-DEC-1994 by SIC; original by Scott I. Chase
: Apparent Superluminal Velocity of Galaxies
: A distant object can appear to travel faster than the speed of light
: relative to us, provided that it has some component of motion
: towards us as well as perpendicular to our line of sight. Say that on
: Jan. 1 you make a position measurement of galaxy X. One
: month later, you measure it again. Assuming you know its distance from
: us by some independent measurement, you derive its
: linear speed, and conclude that it is moving faster than the speed of
: light.
There is no way possible that _any_ galaxy
can appear to be moving _toward_ us at more than a
small percentage of the speed of light, at the
most, maybe a couple of million miles per hour.
The rationale for calculating relative
speeds looks ok, but there is no way that any
galaxy moves _toward_ us at extraordinary speeds.
I'll leave the rest of the message below in case
previous messages are deleted from the server.
Ken Fischer
: What have you forgotten? Let's say that on Jan. 1, the object is D km
mj1...@janus.swipnet.se
kfis...@iglou.com (Ken Fischer) wrote:
Until you have some new explanation, I think it is meaningless to
discuss with you. I think I have made my point (although you don't
understand it), and you keep repeating the same statements over and
over again.
> I'm still working on ways to present the model
>to allow 3D people to understand 4D physics, I won't
>give up, but it is a difficult problem, the restrictions
>of Usenet text modes makes it more difficult.
You can send a binary file. I'm curious to see if you really can
explain dependance of mass and distance.
>: SR does not describe accelerated motion.
Sorry, guess I was wrong.
>: Take another look at QED. In it, photons do just that (of course they
>: only affect charged particles, but the principle is the same)
>: Mathias Ljungberg
> Photons don't "pull" at large distances. If they
>did, you could apply pulsating DC to an antenna, and it
>would either push things or pull them depending on the
>polarity.
> If that works, great, it will make fantastic
>things possible.
Have you heard about electromagnets ? :-)
> But I don't think gravity works
>that way.
I see no reason why not.
BTW, when I referred to the strong nuclear force, I meant the weak.
Ken Fischer
mj1...@janus.swipnet.se wrote:
: Until you have some new explanation, I think it is meaningless to
: discuss with you. I think I have made my point (although you don't
: understand it), and you keep repeating the same statements over and
: over again.
I'm sorry, I became interested in this time dilation
thing, and it is really bothering me. Wayne Thorpe made
several statements about clocks slowing due to velocity,
and also in gravity wells that are deeper, such as Saturn,
which has much more mass than the Earth, but not too different
a surface gravity.
As I have been saying, in Divergent Matter, the surface
of a planet has a hidden upward radial velocity, and it seems
this might allow an explanation why clocks slow due to velocity,
and larger planets have a higher hidden velocity of the surface
in Divergent Matter, and this seems to be consistent.
I can't come up with a new explanation for how
Divergent Matter works, it is a model built on a minimum
of postulates, and it has to support itself.
Do you accept that the surface has a hidden outward
velocity resulting from all past outward acceleration,
and that this velocity is a constant in current meters?
Do you accept that a rocket fired from the surface
increases it's velocity over that of the surface, and
continues on without stopping until the surface catches up?
And this means that any object that appears to stop
it's upward flight and appears to start falling back, is
actually still moving away from the center of the Earth.
This motion enters into the equation of freefall
in Divergent Matter, and accounts for part of the illusion
we observe.
: kfis...@iglou.com (Ken Fischer) wrote:
: > I'm still working on ways to present the model
: >to allow 3D people to understand 4D physics, I won't
: >give up, but it is a difficult problem, the restrictions
: >of Usenet text modes makes it more difficult.
:
: You can send a binary file. I'm curious to see if you really can
: explain dependance of mass and distance.
It isn't the file type, it's partly the resolution, and
I can't prepare a bitmap graphics presentation either, I am
not able.
The acceleration is almost totally proportional to mass,
I don't see how you have a problem with this.
If you have two spheres of the same material, one having
twice the radius of the other, and the first has a 1 g surface
gravity, the second will have a 2 g surface gravity, and this
is true in Newtonian gravitation, and it is true in Divergent
Matter. For the same density material, surface gravity is
directly proportional to radius.
If you can buy this, I'll work on the distance part,
: >: SR does not describe accelerated motion.
: Sorry, guess I was wrong.
That is a common misconception about SR, I think
maybe even some schools teach that SR can't handle acceleration,
but it can very well, it just can't handle gravity.
: >: Take another look at QED. In it, photons do just that (of course they
: >: only affect charged particles, but the principle is the same)
: >: Mathias Ljungberg
: > Photons don't "pull" at large distances. If they
: >did, you could apply pulsating DC to an antenna, and it
: >would either push things or pull them depending on the
: >polarity.
: > If that works, great, it will make fantastic
: >things possible.
:
: Have you heard about electromagnets ? :-)
Yes, and I have seen big ones, and they have very
little range, and only work on certain materials.
A couple of people feel that electrostatic charge
can explain gravity, but I think we would notice the static
electricity.
: > But I don't think gravity works
: >that way.
: I see no reason why not.
It would be nice if it did, we might be able
to control it then, but wishing will not make it so.
That is one thing about Divergent Matter, it
clearly shows that gravity cannot be controlled, it
works perfect all the time.
: BTW, when I referred to the strong nuclear force, I meant the weak.
I'm sure you know more about that than I do,
I do expect more unification than the electro-weak though.
I'm not sure where the forces that hold the quarks
in place comes from.
Ken Fischer
Ken Fischer
: >twice the radius of the other, and the first has a 1 g surface
: >gravity, the second will have a 2 g surface gravity, and this
: >is true in Newtonian gravitation, and it is true in Divergent
: >Matter. For the same density material, surface gravity is
: >directly proportional to radius.
: > If you can buy this, I'll work on the distance part,
:
: objects, the hidden outward velocity makes all objects expand at the
: same rate, and it is the expansion that makes the space between
: objects decrease.
If you are using the physics we observe, only the
acceleration matters, the hidden velocity is totally masked
by the lengthening units of measure.
Even in the underlying physics, things do not expand
at the same rate, they simply double in the same amount of
time, which means that large objects have to expand faster
than small objects, and higher density objects expand more
by acceleration than by residual velocity.
The acceleration part of the expansion makes any
expansion non-linear.
: Can you buy this: the attraction of two objects with stationary mass
: centres is independent of mass and distance?
No, I can't even consider it. The underlying physics
is meaningless to observations made with physical objects and
in flat space or flat spacetime.
Divergent Matter is a model of underlying physics, and
is more revealing in that it separates processes into several
different components.
I consider the fact that Divergent Matter models the
depth of a gravity well as two components, acceleration and
velocity of the surface, and velocity is supposed to be the
cause of time dilation, a fact that surely has some meaning.
It is much easier to perform thought experiments with
the Earth and a test body, and only the acceleration should
be used unless the full worldline history is considered.
: I am certain that I have proved this in my thought experiment. The
: only thing (that I can come up with) that might save your theory is
: motion of the mass centres. Is that what you're trying to show?
If objects are separated, they have a velocity of
separation, yes, in the underlying physics, this must be
considered, else the physics doesn't work.
Even in Newtonian gravitation you have to be sure
to account for motion of mass centers, except in Newtonian
gravitation, much of the physics is all piled into the
apparent attraction simplification.
The underlying physics of Divergent Matter involves
more parameters, and is therefore more basic, but in the
process, the unsatisfactory "action at a distance" thing
is eliminated and a workable physical cause is provided.
: >: > Photons don't "pull" at large distances. If they
: >: >did, you could apply pulsating DC to an antenna, and it
: >: >would either push things or pull them depending on the
: >: >polarity.
: >: > If that works, great, it will make fantastic
: >: >things possible.
: >:
: >: Have you heard about electromagnets ? :-)
:
: > Yes, and I have seen big ones, and they have very
: >little range, and only work on certain materials.
: Photons in action ! They work on electrical charges and some metals
: (in which the atoms behave like small magnets).
: Certainly the range is longer that an atom !
I don't know how electromagnets work, the range is
more than atomic, but falls off faster than light or gravity.
And only certain materials are attracted or repulsed,
while gravity appears to work the same regardless of the
material.
: That's my second objection to your theory. Your net repulsion model.
: It is not necessary if your theory can produce orbital motion (can
: it?).
The net repulsion is still at atomic or molecular
range, it is essentially a contact interaction, that is
why it is additive, and that is how it gets it's great
power in large objects.
I think orbits are a problem, but I still think
General Relativity has the same problem.
: > A couple of people feel that electrostatic charge
: >can explain gravity, but I think we would notice the static
: >electricity.
:
: Yes of course. I don't say that. I just say that if photons can
: explain EM, it is possible that gravity could be explained by exchange
: particles as well. These particles would be attractive only and affect
: all mass.
: Mathias Ljungberg
It is important to separate the propagated spectrum
of EM from the electromagnet part.
The propagated spectrum is not attractive as far as
I know, and isn't even very strong at pushing, it carries
99 percent of it's energy in the transverse component, it
will burn through steel, yet will not lift steel against
against gravity.
I would be only too happy if it was discovered that
an electromagnet could counteract gravity for all known
materials, that would mean that everyone's dreams of space
travel would be easier to achieve.
But in the meantime, I will have to continue to
study Divergent Matter, and try to see how it can provide
the underlying physics of General Relativity.
Ken Fischer
mj1...@janus.swipnet.se
kfis...@iglou.com (Ken Fischer) wrote:
> I'm sorry, I became interested in this time dilation
>thing, and it is really bothering me. Wayne Thorpe made
>several statements about clocks slowing due to velocity,
>and also in gravity wells that are deeper, such as Saturn,
>which has much more mass than the Earth, but not too different
>a surface gravity.
> As I have been saying, in Divergent Matter, the surface
>of a planet has a hidden upward radial velocity, and it seems
>this might allow an explanation why clocks slow due to velocity,
>and larger planets have a higher hidden velocity of the surface
>in Divergent Matter, and this seems to be consistent.
> I can't come up with a new explanation for how
>Divergent Matter works, it is a model built on a minimum
>of postulates, and it has to support itself.
> Do you accept that the surface has a hidden outward
>velocity resulting from all past outward acceleration,
>and that this velocity is a constant in current meters?
> Do you accept that a rocket fired from the surface
>increases it's velocity over that of the surface, and
>continues on without stopping until the surface catches up?
I can accept all you say as possible ways for things to happen.
> The acceleration is almost totally proportional to mass,
>I don't see how you have a problem with this.
I don't.
> If you have two spheres of the same material, one having
>twice the radius of the other, and the first has a 1 g surface
>gravity, the second will have a 2 g surface gravity, and this
>is true in Newtonian gravitation, and it is true in Divergent
>Matter. For the same density material, surface gravity is
>directly proportional to radius.
> If you can buy this, I'll work on the distance part,
I can buy this. But I don't see how the acceleration relates to other
objects, the hidden outward velocity makes all objects expand at the
same rate, and it is the expansion that makes the space between
objects decrease.
Can you buy this: the attraction of two objects with stationary mass
centres is independent of mass and distance?
I am certain that I have proved this in my thought experiment. The
only thing (that I can come up with) that might save your theory is
motion of the mass centres. Is that what you're trying to show?
>: > Photons don't "pull" at large distances. If they
>: >did, you could apply pulsating DC to an antenna, and it
>: >would either push things or pull them depending on the
>: >polarity.
>: > If that works, great, it will make fantastic
>: >things possible.
>:
>: Have you heard about electromagnets ? :-)
> Yes, and I have seen big ones, and they have very
>little range, and only work on certain materials.
Photons in action ! They work on electrical charges and some metals
(in which the atoms behave like small magnets).
Certainly the range is longer that an atom !
That's my second objection to your theory. Your net repulsion model.
It is not necessary if your theory can produce orbital motion (can
it?).
> A couple of people feel that electrostatic charge
Dan Yertzell
Ken Fischer <kfis...@iglou.com> wrote in article <E44K9...@iglou.com>...
> mj1...@janus.swipnet.se wrote:
> : kfis...@iglou.com (Ken Fischer) wrote:
> : > If you have two spheres of the same material, one having
> : >twice the radius of the other, and the first has a 1 g surface
> : >gravity, the second will have a 2 g surface gravity, and this
> : >is true in Newtonian gravitation, and it is true in Divergent
> : >Matter. For the same density material, surface gravity is
> : >directly proportional to radius.
> : > If you can buy this, I'll work on the distance part,
Are you related to (or perhaps the same person) a Joe Fischer who used to
post, many years ago on FidoNet, similar gravity "theories". I remember
"Divergent Matter", and "Parallel World" as being the names of his pet
gravity theory.
The basic idea was that, rather than all matter simply attracting other
matter, all matter is somehow expanding, and this accounts for gravity. We
are not being pulled down to the earth, but instead the earth is pressing
up against our feet.
I recall the major objections at the time were: matter would have to be
*accelerating*, not just expanding, soon going FTL. If matter is
expanding, is it becoming more tenuous, or is each atom getting larger? If
you placed a ball of lead inside a ball of plastic, why doesn't the ball of
lead (which has more mass and therefore more "gravity", and therefore, must
be "expanding" faster) break thru the outer ball of plastic?
My own personal objection: since everything is expanding the same relative
to everything else (i.e. the yardstick expands the same amount as the
object you are trying to measure) this "expansion" can never be observed,
measured or proven. Given this, why go with such a hypothesis. It's like
arguing that the moon is made of cheese, except for when you look at it.
It's pointless, and even *if true*, still is pointless.
Does anyone else here remember Joe Fischer from FidoNet, say 6-7 years ago?
Dan
Ken Fischer
Dan Yertzell (Dan-Ye...@worldnet.att.net) wrote:
: Ken Fischer <kfis...@iglou.com> wrote in article <E44K9...@iglou.com>...
: > mj1...@janus.swipnet.se wrote:
: > : kfis...@iglou.com (Ken Fischer) wrote:
: > : > If you have two spheres of the same material, one having
: > : >twice the radius of the other, and the first has a 1 g surface
: > : >gravity, the second will have a 2 g surface gravity, and this
: > : >is true in Newtonian gravitation, and it is true in Divergent
: > : >Matter. For the same density material, surface gravity is
: > : >directly proportional to radius.
: > : > If you can buy this, I'll work on the distance part,
: Are you related to (or perhaps the same person) a Joe Fischer who used to
: post, many years ago on FidoNet, similar gravity "theories". I remember
: "Divergent Matter", and "Parallel World" as being the names of his pet
: gravity theory.
Yes, I have always gone by that name except on legal
documents.
: The basic idea was that, rather than all matter simply attracting other
: matter, all matter is somehow expanding, and this accounts for gravity. We
: are not being pulled down to the earth, but instead the earth is pressing
: up against our feet.
Sounds consistent with observation to me. :-)
: I recall the major objections at the time were: matter would have to be
: *accelerating*, not just expanding, soon going FTL.
Which is not true according to the meter stick and
second we use, because they both would be lengthening, and
c becomes an observed constant.
The fact that, in the underlying physics, all of
the values go hyperbolic, is not a problem, as long as
what we measure agrres with Newton or General Relativity.
: If matter is
: expanding, is it becoming more tenuous, or is each atom getting larger?
No, we would always observe the same size and density
using the meter stick and second we use, even though, in
the underlying physics, the quarks would be twice as far
apart about every 10 minutes.
As close as the quarks are together, it shouldn't
matter too much, and even though this process of gravity
would involve the entropy of quarks moving apart, it
may be closer to reality than other models.
If
: you placed a ball of lead inside a ball of plastic, why doesn't the ball of
: lead (which has more mass and therefore more "gravity", and therefore, must
: be "expanding" faster) break thru the outer ball of plastic?
The acceleration provides surface gravity, but there
is a hidden residual outward radial velocity of the surface
that is greater for less dense material that allows all
objects to double in the same period of time.
This hidden velocity also seems to provide the
mechanism for some of the relativistic effects. But the
acceleration is all we can measure and observe directly.
: My own personal objection: since everything is expanding the same relative
: to everything else (i.e. the yardstick expands the same amount as the
: object you are trying to measure) this "expansion" can never be observed,
: measured or proven. Given this, why go with such a hypothesis. It's like
: arguing that the moon is made of cheese, except for when you look at it.
: It's pointless, and even *if true*, still is pointless.
The object is to try to have a consistent model,
it isn't a question of "why bother, it's pointless", the
model exists and needs to be studied.
Things in freefall are not accelerated, that is
consistent with observation.
The surface gravity of spheres of like material
is directly proportional to radius, that would be
consistent if such spheres existed as planets, but the
Earth is not homogeneous, the core appears to be very
much compressed, it has a density of about 17, while
the surface has a density of 3 with some local variation.
Check my homepage once in a while, maybe I will
find something interesting to post.
Since I have been working on this for 51 years,
it is about time it was formalized, but I need a lot of
help, and I am getting none.
: Does anyone else here remember Joe Fischer from FidoNet, say 6-7 years ago?
: Dan
Or 8 or 9? :-) But I think I bore people. :-)
Kenneth Edmund Fischer - Inventor of Stealth Shapes - U.S. Pat. 5,488,372
Who's Who of American Inventors Fourth Edition 1996-1997
Divergent Matter GUT of Gravitation http://www.iglou.com/members/kfischer
aka Joe Fischer
Dan Yertzell
Ken Fischer <kfis...@iglou.com> wrote in article <E48qC...@iglou.com>...
>
> : The basic idea was that, rather than all matter simply attracting other
> : matter, all matter is somehow expanding, and this accounts for gravity.
We
> : are not being pulled down to the earth, but instead the earth is
pressing
> : up against our feet.
>
> Sounds consistent with observation to me. :-)
Then how does your "Divergent Matter" explain things like Black Holes.
Indeed, how would planets, stars, and galaxies ever form if not by
accretion and gravity "pulling things together"? I've seen you laugh off
black holes before, presumably because DM cannot explain them. Just this
week, there have been several likely BHs discovered. Currently accepted
gravitational theories *do* explain them, however, and that to me is the
point. Theories consistent with observations.
How about the "slingshot effect" of *falling* into a massive body and then
pulling out at the last moment, to gain a tremendous increase in speed?
This is not hypothetical, but fact and used many times in deep space
missions.
Orbital mechanics in general? Light bending around a "gravitational lens"?
Again, fact.
The fact is, "Divergent Matter" is *not* consistent with observation. When
I jump off a diving board into a swimming pool, I do not hang in the air,
waiting for the pool to come up to me. I *fall* into it. The sensation of
falling is quite distinct, and not at all like being suspended.
DM is a neat idea, but can (and should be) readily dismissed. It's too
convoluted, and cannot be observed, tested or proven. Occam's Razor
applies here. That you have spent 51 years working on this says something,
and I am not at all sure that it's a good something.
Gravity does, in fact, suck.
Dan
Planted firmly in my chair by the "force" of gravity.
Ken Fischer
Dan Yertzell (Dan-Ye...@worldnet.att.net) wrote:
: Ken Fischer <kfis...@iglou.com> wrote in article <E48qC...@iglou.com>.
: > : The basic idea was that, rather than all matter simply attracting other
: > : matter, all matter is somehow expanding, and this accounts for gravity.
: > : We are not being pulled down to the earth, but instead the earth is
: > : pressing up against our feet.
: >
: > Sounds consistent with observation to me. :-)
: Then how does your "Divergent Matter" explain things like Black Holes.
I don't think DM forbids black holes, but it does
change the kinematics, requiring all objects to have surfaces
moving outward radially in the underlying physics, and the
pressure exerted by the gravitation process is from the inside
pushing out, rather than having an "attraction" pulling every
particle towards the center.
Hopefully within a couple of years the photographs
being taken will be analysed and some idea of the chances
of black holes existing will be made, but it is too early
for a definitive belief now, IMO.
: Indeed, how would planets, stars, and galaxies ever form if not by
: accretion and gravity "pulling things together"?
The expansion of atoms is identical to the attraction
of atoms, it just requires a different viewpoint.
The minor differences mean that local heating causes
a faster expansion and more surrounding material appearing
to want to occupy the same space, with the highest heating
being at the interface of the surrounding matter.
This provides a more dynamic coming together of
matter, without any "attraction" required. In cases
where there are local density variations around the
area of the interface of the outflowing matter (which
would appear to us as "attraction"), violent heating
would occur, and even explosions if there is enough
mass and velocity involved.
This would seem to provide the mechanism to control
the size of new stars, with a major explosion/implosion
making a dense star and moving the surrounding matter
away from the new star.
: I've seen you laugh off
: black holes before, presumably because DM cannot explain them.
It seems to me that Newtonian gravitation is
needed to explain black holes, I don't see the "attraction"
process as clearly in General Relativity.
But gravity is gravity, and dense stars do exist,
but I just don't know any more than the next person about
black holes, the idea is kinda new to me, I was studying
astronomy long before I ever heard the word.
: Just this
: week, there have been several likely BHs discovered.
Several likely "candidates", we will have to wait
to see what they are.
: Currently accepted
: gravitational theories *do* explain them, however, and that to me is the
: point. Theories consistent with observations.
Please wait for the observation to see if there
is consistency.
: How about the "slingshot effect" of *falling* into a massive body and then
: pulling out at the last moment, to gain a tremendous increase in speed?
Attraction isn't needed for that, only spacetime
and kinetic energy (or momentum). But you exaggerate
what the slingshot effect does, don't take my word for it,
ask somebody who knows.
: This is not hypothetical, but fact and used many times in deep space
: missions.
Yes, and it works best with a rocket burn at the
lowest point.
: Orbital mechanics in general? Light bending around a
: "gravitational lens"?
: Again, fact.
About the same as General Relativity, you explain
how it works in General Relativity, and I will try to
show the equivalence.
: The fact is, "Divergent Matter" is *not* consistent with observation.
Neither is Newtonian gravitation, but not enough
is known about Divergent Matter, it is too difficult for
one person to cover all the various processes.
: When
: I jump off a diving board into a swimming pool, I do not hang in the air,
: waiting for the pool to come up to me. I *fall* into it. The sensation of
: falling is quite distinct, and not at all like being suspended.
You should have quit when you were ahead. :-)
Talk to freefall parachutists.
: DM is a neat idea, but can (and should be) readily dismissed.
Why? I don't dismiss Newtonian gravitation even
though I know it is not correct (I do dismiss ether theories
though). :-) (Sorry Henry). :-)
: It's too
: convoluted, and cannot be observed, tested or proven.
Somebody has a lot of work to do, and a lot to
look forward to.
: Occam's Razor applies here.
Ok, great, Divergent Matter is the least complicated,
requiring nothing other than for quarks to not have enough
binding energy to maintain constant size.
Newtonian gravitation requires magic to "pull" things
toward each other, and computers to specify how hard to pull.
General Relativity requires spacetime to have some
unknown property that causes the inertial coordinate system
to have an affinity for massive objects.
: That you have spent 51 years working on this says something,
: and I am not at all sure that it's a good something.
I am happy with it, I hope it doesn't make too many
people unhappy, but continuing education is pretty much
required where gravitation and astrophysics is concerned.
: Gravity does, in fact, suck.
: Dan
: Planted firmly in my chair by the "force" of gravity.
Tell me how it works and I'll go away happy.
Ken Fischer
John DeHaven
Dan Yertzell <Dan-Ye...@worldnet.att.net> wrote in article
> How about the "slingshot effect" of *falling* into a massive body and
then
> pulling out at the last moment, to gain a tremendous increase in speed?
> This is not hypothetical, but fact and used many times in deep space
> missions.
You know I've read about this and I guess I believe in it, but I'm darned
if I can see how it works. It seems to me that, on elementary principles,
it would consume *exactly* as much energy to climb back out of a gravity
well as you gain by falling into it. Yet "more speed" sounds like more
energy to me. Something for nothing? Where does the new spacecraft kinetic
energy come from in this trick?
(My best guess is that it somehow *must* be stolen from the massive body,
but what's stolen and how? By the same principles, it seems like the
massive body must use up exactly as much energy "climbing away" from your
spaceship as it did "falling near" to it, however slight that motion might
be.)
What are the limitations? Why couldn't the trick be repeated as many times
as you please to give your spacecraft *any* arbitrary speed < c more or
less for free? (Or until your massive body is used up, or whatever happens
to it?) That can't be possible or else there would not be so much
discussion about how to build feasible starships. But it is less than
obvious why this can only be a one-time trick.
And, for the matter of that, what's the upper limit of the gain you can get
by doing the trick *once*?
--
My header has been modified to attempt to foil junk-mail robots.
jo...@mozart.inet.co.th
Kakargias Athanasios
John DeHaven wrote:
>
> Dan Yertzell <Dan-Ye...@worldnet.att.net> wrote in article
> > How about the "slingshot effect" of *falling* into a massive body and
> then
> > pulling out at the last moment, to gain a tremendous increase in speed?
crashing with each other ,though in space there is no impact but
gravity in this case is the medium
thAnos
S. McPhail
On 20 Jan 1997, John DeHaven wrote:
>
> Dan Yertzell <Dan-Ye...@worldnet.att.net> wrote in article
> > How about the "slingshot effect" of *falling* into a massive body and
> then
> > pulling out at the last moment, to gain a tremendous increase in speed?
> > This is not hypothetical, but fact and used many times in deep space
> > missions.
>
> You know I've read about this and I guess I believe in it, but I'm darned
> if I can see how it works. It seems to me that, on elementary principles,
> it would consume *exactly* as much energy to climb back out of a gravity
> well as you gain by falling into it. Yet "more speed" sounds like more
> energy to me. Something for nothing? Where does the new spacecraft kinetic
> energy come from in this trick?
It comes from the orbital KE of the planet.
> (My best guess is that it somehow *must* be stolen from the massive body,
> but what's stolen and how? By the same principles, it seems like the
> massive body must use up exactly as much energy "climbing away" from your
> spaceship as it did "falling near" to it, however slight that motion might
> be.)
This is true in the satelite-planet frame but not in the satelite-sun
frame. The slingshot effect is due to a three body interaction involving
the satelite, the planet and the star. As the the satelite approachs the
planet it is accelerated by the planets gravity towards it. As it moves
away from the planet it is decelerated by the planets gravity back towards
the planet.
However in the mean time the planet has moved in is orbit slightly, this
means that the acceleration and deceleration are not co-linear - there is
a slight acceleration 'left over' (try drawing this on a piece of paper)
which produces the slingshot effect. Momentum is conserved between the
satelite and planet, the planet is slightly decelerated and the satelite
picks up some velocity.
> What are the limitations? Why couldn't the trick be repeated as many times
> as you please to give your spacecraft *any* arbitrary speed < c more or
> less for free? (Or until your massive body is used up, or whatever happens
> to it?) That can't be possible or else there would not be so much
> discussion about how to build feasible starships. But it is less than
> obvious why this can only be a one-time trick.
It could providing that the spacecraft can match orbits with a sufficient
number of planets (this is the idea behind the Voyager 'grand tours' of
the outer planets - the alignment of the planets was such that it could
intercept each of them and slingshot to the next without having to carry
any fuel). I'd guess that the amount of velocity that it is possible to
pick up by this means just isn't enough for practical intersteller travel
(once you exceed solar escape velocity you are out of the solar system and
there are no more planets to accelerate you).
> And, for the matter of that, what's the upper limit of the gain you can get
> by doing the trick *once*?
Sorry, don't know off hand but it depends on the mass of the planet, its
distance from the sun and the planet's radius - the deeper into the
gravity well the more acceleration you get (so long as you don't hit the
atmosphere).
> jo...@mozart.inet.co.th
Sean
------------------------------------------------------------------------
Sean McPhail /\ /\ /\ /\ /\ /E-mail: sm1...@hermes.cam.ac.uk
Robinson College / \/ \/ \/ \/ \/ Tel : (+44) 01223 339100
Cambridge /\/\ I`d rather have a bottle in\ /\ /\ /\ /\ /\ /\
CB3 9AN / front of me than a frontal lobotomy\/ \/ \/ \/ \/ \/ \/
------------------------------------------------------------------------
Ken Fischer
John DeHaven (jo...@mozart.inet.co.th.remove) wrote:
: Dan Yertzell <Dan-Ye...@worldnet.att.net> wrote in article
: > How about the "slingshot effect" of *falling* into a massive body and
: then
: > pulling out at the last moment, to gain a tremendous increase in speed?
: > This is not hypothetical, but fact and used many times in deep space
: > missions.
: You know I've read about this and I guess I believe in it, but I'm darned
: if I can see how it works. It seems to me that, on elementary principles,
: it would consume *exactly* as much energy to climb back out of a gravity
: well as you gain by falling into it. Yet "more speed" sounds like more
: energy to me. Something for nothing? Where does the new spacecraft kinetic
: energy come from in this trick?
Correct, the statement you responded to does not
reflect exactly what happens.
If a rocket burn is not used to increase energy,
only the vector is changed, but when the vector is changed,
there is the appearance of increased speed.
The early Soviet moon shots show clearly what happens
when a spacecraft passes planets and moons without mid-flight
correction rocket burns. Some of the flights went around
the moon, back around the Earth and back toward the moon,
and then ran out of energy, you would have to see the 2D
graphs to be able to appreciate it.
: (My best guess is that it somehow *must* be stolen from the massive body,
: but what's stolen and how? By the same principles, it seems like the
: massive body must use up exactly as much energy "climbing away" from your
: spaceship as it did "falling near" to it, however slight that motion might
: be.)
Right again, but vector changes are accomplished by
precise launch guidance and a correction burn or so.
: What are the limitations? Why couldn't the trick be repeated as many times
: as you please to give your spacecraft *any* arbitrary speed < c more or
: less for free? (Or until your massive body is used up, or whatever happens
: to it?) That can't be possible or else there would not be so much
: discussion about how to build feasible starships. But it is less than
: obvious why this can only be a one-time trick.
: And, for the matter of that, what's the upper limit of the gain you can get
: by doing the trick *once*?
Orbital mechanics only allows certain trajectories,
so the position of the planets and moons restricts what is
possible at any one time.
Several magazines publish this kind of information
for each space mission as it takes place, see "Astronomy",
"Sky and Telescope", "Aviation Week and Space Technology",
etc.
Ken Fischer
Bill Oertell
Imagine this: a satellite approaches a planet on a trajectory that
takes it just behind the planet's orbital path with enough velocity to
escape that planet's gravity. Once the satellite exits on the other
side of the planet's orbit, it will have gained that planet's orbital
velocity.
--
Bill
John DeHaven
Kakargias Athanasios <stud...@di.uoa.gr> wrote in article
<32E37C4F...@di.uoa.gr>...
> John DeHaven wrote:
> >
> > Dan Yertzell <Dan-Ye...@worldnet.att.net> wrote in article
> > > How about the "slingshot effect" of *falling* into a massive body and
> > then
> > > pulling out at the last moment, to gain a tremendous increase in
speed?
> crashing with each other ,though in space there is no impact but
> gravity in this case is the medium
Not helpful yet. I don't see that the smaller ball would gain any net speed
from any such collision. Indeed if I bounce a tennis ball off the earth, it
never rebounds at a higher speed. Nor would any perfectly elastic ball in
some lossless bounce.
Dan Evens
Regarding the slingshot effect, also known as a gravity assist.
John DeHaven wrote:
> You know I've read about this and I guess I believe in it, but I'm darned
> if I can see how it works. It seems to me that, on elementary principles,
> it would consume *exactly* as much energy to climb back out of a gravity
> well as you gain by falling into it. Yet "more speed" sounds like more
> energy to me. Something for nothing? Where does the new spacecraft kinetic
> energy come from in this trick?
>
> (My best guess is that it somehow *must* be stolen from the massive body,
> but what's stolen and how? By the same principles, it seems like the
> massive body must use up exactly as much energy "climbing away" from your
> spaceship as it did "falling near" to it, however slight that motion might
> be.)
Here is an easy way to think of this. There is a frame of reference in
which the total momentum of the planet and the rocketship is zero.
Now, in this frame, the planet is NEARLY at rest, because the planet is
hugely more massive than the rocketship. Call this frame planet-at-rest.
(The planet is not quite at rest in this frame, but it is very nearly
so.
It's velocity will be smaller than the rocketships by the ratio of their
masses.)
In this frame, your guess is pretty much correct. The ship goes down
to some point then starts back up. It comes back up with exactly the
same kinetic energy as it started with, because gravity is conservative
(at least if you neglect things like gravity waves). But, the direction
has changed. The planet will also do the same thing, just at a MUCH
smaller velocity, again because it has a much bigger mass.
So for a very special case of the rocket making a total 90 degree
turn in its encounter, in the planet-at-rest frame it looks like so.
^
|
|
|
|
0
______________
That's supposed to be a rocket that commes in from the bottom left
and goes out the top. Suppose that a long way from the planet it
is moving at speed v to start, then after it moves a long way
away from the planet after the encounter, it must be moving at v
again.
Now change to the frame of reference which includes the sun's
momentum as well as the planet and rocket. In this frame, since
the sun is more massive still, the sun is nearly at rest.
Suppose, for a simple to understand example, that the planet
has a velocity magnitdue D, and direction straight up in
the picture. Then, in the sun-at-rest frame, we get that
the incoming rocket has a velocity of v to the left and D up,
and after it has a velocity of v+D up and zero to the left.
Like so.
^
|
|
|
|
0
\
\
\
\
\
So, before, it has a kinetic energy of 1/2 m (v^2 + D^2)
and after it has a kinetic energy of 1/2 m (v^2 + 2 v D + D^2)
or m v D more than it started with.
So, in this special case of a simplified example, you can
see that what has happened is the rocket has managed to
get some of the planet's kinetic energy.
For an exercise, you might re-do this including the motion of
the planet and the sun, and you might look for the change of
angle and angle of approach that produces the largest and
smallest changes in kinetic energy of the rocket.
You can also do keen things by firing the rocket at various
points in the encounter. For example, is it the case that
firing the rocket at the closest approach produces the
biggest effect, and why.
--
Standard disclaimers apply.
I don't buy from people who advertise by e-mail.
I don't buy from their ISPs.
Dan Evens
me...@cars3.uchicago.edu
In article <01bc076b$fb334e70$610597cb@JX>, "John DeHaven" <jo...@mozart.inet.co.th.remove> writes:
>Kakargias Athanasios <stud...@di.uoa.gr> wrote in article
><32E37C4F...@di.uoa.gr>...
>> i guess it is the same as two balls 1 of great mass and one of lesser
>> crashing with each other ,though in space there is no impact but
>> gravity in this case is the medium
>
>Not helpful yet. I don't see that the smaller ball would gain any net speed
>from any such collision. Indeed if I bounce a tennis ball off the earth, it
>never rebounds at a higher speed. Nor would any perfectly elastic ball in
>some lossless bounce.
It all depends on reference point. Lets repeat your experiment
(bouncing a tennis ball of Earth) but measuring relative to the Sun.
So assume (damn ASCII, cannot even draw with it) on the leading edge
of Earth, in its motion around the Sun (at about 30 km/s). Now you
throw your tennis ball downward, so that it hits the ground at
10 m/sec, relative to Earth, which translates to 29.99 km/sec relative
to the sun. Right after the bounce you get 10 m/s relative to earth
(in the opposite direction now) and 30.01 km/s relative to the sun.
You just gained 20 m/s relative to the Sun.
Mati Meron | "When you argue with a fool,
me...@cars.uchicago.edu | chances are he is doing just the same"
Dan Yertzell
Ken Fischer <kfis...@iglou.com> wrote in article <E4Ap4...@iglou.com>...
>
> : It's too
> : convoluted, and cannot be observed, tested or proven.
>
> Somebody has a lot of work to do, and a lot to
> look forward to.
>
> : Occam's Razor applies here.
>
> Ok, great, Divergent Matter is the least complicated,
> requiring nothing other than for quarks to not have enough
> binding energy to maintain constant size.
> Newtonian gravitation requires magic to "pull" things
> toward each other, and computers to specify how hard to pull.
> General Relativity requires spacetime to have some
> unknown property that causes the inertial coordinate system
> to have an affinity for massive objects.
But where are the computers to specify how fast each object must be
expanding, so as to maintain the same relative sizes? Where does the
magical "residual velocity" come from, and how is it *exactly* the right
velocity to maintain the relative size (ie lead ball inside a plastic
ball)?
TANSTAAFL.
What about tidal forces in the Earth - Moon system. How would a simple
expansion explain that, with no "action at a distance", for lack of a
better term? How is the moon "gravitationally locked", so the same side is
always facing the earth?
And finally, can my waistline's residual velocity be slowed down, so it
expands at the same rate as everything else? :-) Sorry, couldn't resist
that one!
You know, up until a year or maybe 18 months ago, I still had alot of the
posts from the old FidoNet science echo, between you and the denizens of
that echo. They made for fascinating reading. I wish I still had them.
Dan
Paul F. Dietz
"John DeHaven" <jo...@mozart.inet.co.th.remove> wrote:
>Not helpful yet. I don't see that the smaller ball would gain any net speed
>from any such collision. Indeed if I bounce a tennis ball off the earth, it
>never rebounds at a higher speed. Nor would any perfectly elastic ball in
>some lossless bounce.
It would not gain net speed *in the frame of the earth.* It would in
some other reference frame (for example, that of the sun.)
The usual example is: toss the tennis ball in front of an oncoming
truck. After the bounce it is travelling faster (w.r.t. you) than it
was before the bounce.
For gravitational slingshots, substitute a planet for the truck and
a spacecraft for the tennis ball.
Another variety of gravitational slingshot is the increased efficiency
of rocket propulsion deep in gravity wells. This is a consequence of
the fact that the thrust of a rocket in independent of the speed of
the spaceship, while the rate of work done on the spaceship in a
reference frame equals the vector product of thrust and velocity.
More total work is done on the spacecraft if it is moving fast at
periapsis of an orbit. The energy comes from the gravitational
potential energy of the expelled reaction mass.
Paul
Ken Fischer
Dan Yertzell (Dan-Ye...@worldnet.att.net) wrote:
: Ken Fischer <kfis...@iglou.com> wrote in article <E4Ap4...@iglou.com>...
: > : Occam's Razor applies here.
: > Ok, great, Divergent Matter is the least complicated,
: > requiring nothing other than for quarks to not have enough
: > binding energy to maintain constant size.
: > Newtonian gravitation requires magic to "pull" things
: > toward each other, and computers to specify how hard to pull.
: > General Relativity requires spacetime to have some
: > unknown property that causes the inertial coordinate system
: > to have an affinity for massive objects.
: But where are the computers to specify how fast each object must be
: expanding, so as to maintain the same relative sizes?
This is the underlying physics of matter, and the
relative sizes are the result of the acceleration-velocity
combination. I would like to study this in relation to
the periodic table and density of the elements, but I'm
too busy answering questions. :-)
: Where does the magical "residual velocity" come from, and how is it
: *exactly* the right velocity to maintain the relative size (ie lead ball
: inside a plastic ball)?
: TANSTAAFL.
Why would velocity resulting from acceleration be magical,
At t_0 there was the Big Bang, t_0.5 was about ten minutes ago,
t_1 is now. In about ten minutes, things will double in size,
but we will only observe the acceleration part and call it gravity.
: What about tidal forces in the Earth - Moon system. How would a simple
: expansion explain that, with no "action at a distance", for lack of a
: better term?
All particles in moving bodies try to follow their own
geodesic, the higher the orbit, the slower they move, so there
is a natural relative motion between particles.
But spacetime can not be Euclidean, and Mach should not
be mentioned, the geometry of geodesic motion is determined
by the kinematics of moving bodies.
: How is the moon "gravitationally locked", so the same side is
: always facing the earth?
There is a large volume of denser matter within the
side of the Moon facing Earth. I suppose this wasn't known
until spacecraft started orbiting the Moon.
So this waters down the "gravitationally locked"
thing, it is really "gravity stabilized", a tidal effect.
(Thanks for reminding me of this in relation to
Divergent Matter).
: And finally, can my waistline's residual velocity be slowed down, so it
: expands at the same rate as everything else? :-) Sorry, couldn't resist
: that one!
Sure, if you eat less, exercise more. :-)
: You know, up until a year or maybe 18 months ago, I still had alot of the
: posts from the old FidoNet science echo, between you and the denizens of
: that echo. They made for fascinating reading. I wish I still had them.
: Dan
I still have (probably all of) them, plus those from
a couple of other nets, GT and RIME. I should make hard
copies to assure I don't lose them.
At the moment I am looking for my copy of Stephen
Hawking's 1971 Gravity Research Foundation $1,000 prize
winning essay on black holes.
I would like to buy any material published or
distributed by Gravity Research Foundation, I have just
the winning essays from 1949 to 1971.
Incidentally, I entered the 1972 competition,
and was an also ran, and an honorable mention went to
a _Clifford Will_ that year. :-)
There is a vast quantity of literature about
gravitation theory, but very little of it is available
anyplace.
John DeHaven
Paul F. Dietz <di...@interaccess.com> wrote in article
<5c3ofn$6...@nntp.interaccess.com>...
> "John DeHaven" <jo...@mozart.inet.co.th.remove> wrote:
>
> >Not helpful yet. I don't see that the smaller ball would gain any net
speed
> >from any such collision. Indeed if I bounce a tennis ball off the earth,
it
> >never rebounds at a higher speed. Nor would any perfectly elastic ball
in
> >some lossless bounce.
>
> It would not gain net speed *in the frame of the earth.* It would in
> some other reference frame (for example, that of the sun.)
>
> The usual example is: toss the tennis ball in front of an oncoming
> truck. After the bounce it is travelling faster (w.r.t. you) than it
> was before the bounce.
>
> For gravitational slingshots, substitute a planet for the truck and
> a spacecraft for the tennis ball.
Excellent! Settles that, then. How's my grok now:
You can't pull the slingshot trick any old whichaway, but only (to make a
profit) in such a way that it steals some of the orbital energy of the
massive body. This also means you can't do it with just any old relatively
massive body at any time, but only with one that is moving in such a way
that you can get a profit out of it. (If you want balls to go east faster,
bouncing them off of trucks going north isn't going to help you.)
The energetics are like if you bounce the ball off the front of the truck,
not only does the ball rebound more quickly, but the truck is slowed down
slightly. And if you bounce it off the rear of the truck, the ball rebounds
more slowly and you've pushed the truck along slightly.
So in respect to (the frame of reference of) travel within the solar
system, you could pull the trick with planets or large moons, but not with
the sun itself.
And as to extrasolar travel, we _already_ share the proper motion of the
sun in respect to some extrasolar frame of reference, but aliens from
starsystem X on their way to starsystem Y might find a slingshot around the
sun helpful for their trip if it's moving in the direction they want to go,
in their perspective.
This gives some feeling for the limits also: each slingshot trick drains
off a tad of orbital energy from the planet or moon. So keep doing that, or
do it with bigger spaceships, and eventually there would not be any more
useful (to you) orbital energy left. (And the orbit will have decayed,
probably badly enough for it to have spiraled into its primary.) Like if
you kept up a barrage of tennis balls long enough, you would stop the
truck, and you would stop it with fewer balls if you threw bowling balls
(at the same speed).
Miles Collins
In article <01bc06c0$3187c480$0f02000a@jx>,
"John DeHaven" <jo...@mozart.inet.co.th.remove> writes:
>
> Dan Yertzell <Dan-Ye...@worldnet.att.net> wrote in article
>> How about the "slingshot effect" of *falling* into a massive body and
> then
>> pulling out at the last moment, to gain a tremendous increase in speed?
>> missions.
>
> if I can see how it works. It seems to me that, on elementary principles,
> it would consume *exactly* as much energy to climb back out of a gravity
> well as you gain by falling into it. Yet "more speed" sounds like more
> energy to me. Something for nothing? Where does the new spacecraft kinetic
> energy come from in this trick?
It only can work on ROTATING big masses, by slowing that big mass a tiny amount
thus accelerating a small mass a great deal. Like with billard balls, the total
impulse remains constant (p=m*v).
--
feline Greetings ............. /M\
Ka...@ON-Luebeck.de Miles (o,o)<mauz!
(felis cyberspaciensis Collins)(___)
me...@cars3.uchicago.edu
In article <E4FLz...@kater586.on-luebeck.de>, ka...@kater586.on-luebeck.de (Miles Collins) writes:
>In article <01bc06c0$3187c480$0f02000a@jx>,
> "John DeHaven" <jo...@mozart.inet.co.th.remove> writes:
>>
>> Dan Yertzell <Dan-Ye...@worldnet.att.net> wrote in article
>>> How about the "slingshot effect" of *falling* into a massive body and
>> then
>>> pulling out at the last moment, to gain a tremendous increase in speed?
>>> This is not hypothetical, but fact and used many times in deep space
>>> missions.
>>
>> You know I've read about this and I guess I believe in it, but I'm darned
>> if I can see how it works. It seems to me that, on elementary principles,
>> it would consume *exactly* as much energy to climb back out of a gravity
>> well as you gain by falling into it. Yet "more speed" sounds like more
>> energy to me. Something for nothing? Where does the new spacecraft kinetic
>> energy come from in this trick?
>
>It only can work on ROTATING big masses, by slowing that big mass a tiny amount
>thus accelerating a small mass a great deal. Like with billard balls, the total
>impulse remains constant (p=m*v).
No, nothing to do with "rotating".
me...@cars3.uchicago.edu
In article <E4Iz2...@news.uwindsor.ca>, Bill MacArthur <bil...@uwindsor.ca> writes:
>direction of revolution and the mass's velocity, the craft is
>accelerated. The craft "falls" toward the mass longer and receives more
>acceleration than it loses in breaking free. If the craft were to
>approach from a retrograde direction it would be decelerated.
>
It has to do with relative velocities, but whether the motion is part
of a "revolution trajectory" or not is irrelevant.
Bill MacArthur
David L Evens
Bill MacArthur (bil...@uwindsor.ca) wrote:
GR predicts that the spacetime near a rotating black hole will be, in a
sense, dragged arround with the rotation. This can, in principle, also
be used to produce a slingshot effect.
--
---------------------------+--------------------------------------------------
Ring around the neutron, | "OK, so he's not terribly fearsome.
A pocket full of positrons,| But he certainly took us by surprise!"
A fission, a fusion, +--------------------------------------------------
We all fall down! | "Was anybody in the Maquis working for me?"
---------------------------+--------------------------------------------------
"I'd cut down ever Law in England to get at the Devil!"
"And what man could stand up in the wind that would blow once you'd cut
down all the laws?"
------------------------------------------------------------------------------
This message may not be carried on any server which places restrictions
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e-mail will be posted as I see fit.
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me...@cars3.uchicago.edu
In article <5cbo5g$f...@ccshst05.cs.uoguelph.ca>, dev...@uoguelph.ca (David L Evens) writes:
>Bill MacArthur (bil...@uwindsor.ca) wrote:
>: me...@cars3.uchicago.edu wrote:
>: >In article <E4FLz...@kater586.on-luebeck.de>, ka...@kater586.on-luebeck.de (Miles Collins) writes:
>
>: >>It only can work on ROTATING big masses, by slowing that big mass a tiny amount
>: >>thus accelerating a small mass a great deal. Like with billard balls, the total
>: >>impulse remains constant (p=m*v).
>: >
>: >No, nothing to do with "rotating".
>: >
>: It seems to me that it's revolving masses. By taking advantage of the
>: direction of revolution and the mass's velocity, the craft is
>: accelerated. The craft "falls" toward the mass longer and receives more
>: acceleration than it loses in breaking free. If the craft were to
>: approach from a retrograde direction it would be decelerated.
>
>GR predicts that the spacetime near a rotating black hole will be, in a
>sense, dragged arround with the rotation. This can, in principle, also
>be used to produce a slingshot effect.
>
we're talking about.
AMa...@compuserve.com
>: My own personal objection: since everything is expanding the same relative
>: to everything else (i.e. the yardstick expands the same amount as the
>: object you are trying to measure) this "expansion" can never be observed,
>: measured or proven. Given this, why go with such a hypothesis. It's like
>: arguing that the moon is made of cheese, except for when you look at it.
>: It's pointless, and even *if true*, still is pointless.
article that disproves it. You could interpret it as energy density goes to zero, speed
goes to C. Energy density is compared as a log value, so the air you breath and
a rock is on the same order of magnitude and would expand at a similar rate. A
local expanse would explain why photons move, they are dragged along by the
expanse. A build up of mass as an object approches the speed of light is simply
mass expanding into itself. The event horizon of a black hole is zero time and zero
expanse. Use the math in the article referenced by Misner Wheeler and Thorne
to make your arguments. I think a local expanse is more plausible than saying you
only have an expanse at extremely large distances and we don't know exactly
what the distances are. Its also a neat explanation of why photons move.
David L Evens
me...@cars3.uchicago.edu wrote:
This is the kind of slingshot effect that works arround a rotating body,
regardless of any other motions that an observer might see it as having.
I was simply pointing out that there is a slingshot effect that depends
on rotation of the more massive body.
me...@cars3.uchicago.edu
In article <5cjchj$d...@ccshst05.cs.uoguelph.ca>, dev...@uoguelph.ca (David L Evens) writes:
>me...@cars3.uchicago.edu wrote:
>: In article <5cbo5g$f...@ccshst05.cs.uoguelph.ca>, dev...@uoguelph.ca (David L Evens) writes:
>: >
>: >sense, dragged arround with the rotation. This can, in principle, also
>: >be used to produce a slingshot effect.
>: >
>: True. But this is a different type of slingshot from the mundane one
>: we're talking about.
>
>This is the kind of slingshot effect that works arround a rotating body,
>regardless of any other motions that an observer might see it as having.
>I was simply pointing out that there is a slingshot effect that depends
>on rotation of the more massive body.
>
reasonable masses (such as Jupiter).
David L Evens
me...@cars3.uchicago.edu wrote:
: In article <5cjchj$d...@ccshst05.cs.uoguelph.ca>, dev...@uoguelph.ca (David L Evens) writes:
: >me...@cars3.uchicago.edu wrote:
: >: In article <5cbo5g$f...@ccshst05.cs.uoguelph.ca>, dev...@uoguelph.ca (David L Evens) writes:
: >: >
: >: >GR predicts that the spacetime near a rotating black hole will be, in a
: >: >sense, dragged arround with the rotation. This can, in principle, also
: >: >be used to produce a slingshot effect.
: >: >
: >: True. But this is a different type of slingshot from the mundane one
: >: we're talking about.
: >
: >This is the kind of slingshot effect that works arround a rotating body,
: >regardless of any other motions that an observer might see it as having.
: >I was simply pointing out that there is a slingshot effect that depends
: >on rotation of the more massive body.
: >
: No argument here. However, try to estimate its magnitude for
: reasonable masses (such as Jupiter).
It's going to be down there in the noise someplace, certainly. After
all, Newtonian mechanics is a pretty good approximation for gravity for
Jupiter, and it doesn't include such effects.
Ken Fischer
me...@cars3.uchicago.edu wrote:
: dev...@uoguelph.ca (David L Evens) writes:
: >This is the kind of slingshot effect that works arround a rotating body,
: >regardless of any other motions that an observer might see it as having.
: >I was simply pointing out that there is a slingshot effect that depends
: >on rotation of the more massive body.
: No argument here. However, try to estimate its magnitude for
: reasonable masses (such as Jupiter).
: Mati Meron | "When you argue with a fool,
: me...@cars.uchicago.edu | chances are he is doing just the same"
Mati, please remove the TAB character from you sig.
Frame dragging is a misconception of General Relativity, IMO,
and I feel that if it were true, the rotation of the Sun would
have a very noticable effect on the orbits of the inner planets,
is there one?
Kevin Barrett Elliott
me...@cars3.uchicago.edu wrote:
>
> In article <5cbo5g$f...@ccshst05.cs.uoguelph.ca>, dev...@uoguelph.ca (David L Evens) writes:
> >Bill MacArthur (bil...@uwindsor.ca) wrote:
> >: me...@cars3.uchicago.edu wrote:
> >: >In article <E4FLz...@kater586.on-luebeck.de>, ka...@kater586.on-luebeck.de (Miles Collins) writes:
> >
> >: >>It only can work on ROTATING big masses, by slowing that big mass a tiny amount
> >: >>thus accelerating a small mass a great deal. Like with billard balls, the total
> >: >>impulse remains constant (p=m*v).
> >: >
> >: >No, nothing to do with "rotating".
> >: >
> >: It seems to me that it's revolving masses. By taking advantage of the
> >: direction of revolution and the mass's velocity, the craft is
> >: accelerated. The craft "falls" toward the mass longer and receives more
> >: acceleration than it loses in breaking free. If the craft were to
> >: approach from a retrograde direction it would be decelerated.
> >
> >sense, dragged arround with the rotation. This can, in principle, also
> >be used to produce a slingshot effect.
> >
> True. But this is a different type of slingshot from the mundane one
> we're talking about.
My understanding of how a slingshot, more properly called a gravity-
assist maneuver, works, is that any Keplarian trajectory (a very good
approximation of any real trajectory is based on his two-body
equations) follows circular, ovoid, parabolic, or hyperbolic shape,
and in practical analysis, only ovoid or hyperbolic trajectories are
used. Now, a gravity assist is that process by which a spacecraft
goes from heliocentric (or some major body) to planet-centric (or some
other more minor body orbiting said major body) trajectories. While
the planet's gravitation is significantly greater than that of the
major (solar) body, the craft follows a hyperbolic trajectory around
the planet, leaving the planet's gravitational influence at some
point on a new heliocentric orbit. As I recall, the period in which
a craft remains on a trajectory influenced by the planet is on the
order of about a hundred or so days. The new heliocentric orbit of
the vehicle has significantly different characteristics (energy, semi-
major and semi-minor axes (if elliptical, which is most likely), and
so on) from the pre-planetary encounter. It is this difference of
actual trajectory that the engineers use to decrease the energy (fuel)
requirements of a spacecraft, and judicious and well-planned use of
a gravity-assist can even decrease mission time, I believe, but it can
also increase mission time. It is, I believe, the energy savings that
are most important, as the mass ratio of a reaction-mass driven craft
to get directly from Earth to Mars is most optimally just over 20,
meaning a craft must be equipped with 20 times the payload mass in
fuel. Passage to Jupiter is significantly more expensive.
Please correct anything I've mentioned that is incorrect, but I'm
fairly sure that the mechanism of a gravity-assist, or slingshot, is
based primarily on Keplarian mechanics, and nothing to do at all with
rotation of the planetary body, though its revolution does affect the
characteristics of the transfer orbits (pre-entry, planetary influence,
and post-exit) necessary for a fairly accurate preliminary analysis.
Of course, more sophisticated multiple-body analyses actually drive
a final mission profile, but the physics are based in Kepler.
Cheers,
-Kevin ;-)
--
Kevin Elliott Simplicity is the Essence of Reality
122 Gildersleeve Newcomb Hall
Charlottesville, VA 22904
(804) 243 2237
kb...@watt.seas.virginia.edu
kb...@cs.virginia.edu