Chatroom
 

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Go Back   Bad Astronomy and Universe Today Forum > The Proving Grounds > Against the Mainstream
Register FAQ Members List Calendar Mark Forums Read

   

Closed Thread
 
LinkBack Thread Tools Display Modes
  #1 (permalink)  
Old 22-February-2004, 05:49 PM
Lunatik Lunatik is offline
Established Member
 
Join Date: Feb 2004
Location: California, USA
Posts: 555
Default Dark Matter & Quantum Gravity

:P
In two recent issues of Scientific American, Jan-Feb 2004, there are articles discussing Quantum Gravity and Dark Energy/Matter. The articles are very interesting, but the authors leave us with an impression that what we think we understand is somehow incomplete.

A much simpler way to understand gravity at a great distance from us would be to postulate that it is not a flat universal constant, as now believed, or as theorized by both Newtonian Classical physics and Einstein's General Relativity, but rather is a 'variable-constant' depending upon where it is measured. This would imply that gravity is not all the same everywhere, and may be weaker near a hot star, as measured in terms of mass inertia, and greater when far away from it, such as on the edge of our solar system or deep in space. One piece of evidence to bear this out is the slowing of the two Pioneer spacecrafts leaving our solar system, which could be understood as greater gravity equals greater inertia. If momentum is constant, then the greater gravity per mass out there would of necessity slow them down.

Has anyone seen more on this mysterious development? A possible explanation could be achieved with the photoelectric equation applied to Einstein's famour formula:

hc/L(m) = mc^2, where:

h = Planck's constant, 6.26e-34
c = lightspeed constant, 3e8
L = deBroglie lambda for proton (m)
(m) = 1.67e-27
m = mass = 1 kg

This equation, if rewritten as:

hc/L(m) = (1-g)c^2, where:

1 = mass
g = proton to proton gravitational constant, ~5e-39,

gives us an inverse proportion for L and g.

The result is that the atom as formed by these equations, proton mass, is an incomplete 'combustion' of electromagnetic energy, so that some force of gravity remains as a very weak force. If the EM energy is greater, this force becomes lesser; conversely, if the EM energy is lower, lower lambda, then the gravitational remainder is greater.

None of this has found its way into conventional physics, however, so must be treated with great suspicion until we have some evidence that gravity is not the same everywhere, but is some inverse function of the electromagnetic energy put out by the local star instead. The result would be very great gravity for weak, or cool stars, such as neutron or brown stars. Out in the cold of deep space, this greater gravity may account for the so-called 'dark matter'.

Anyway, call it badastronomy, but it may be a possibility that better explains other cosmic phenomena, such as lightredshift from distant quasars, etc. If light redshifts through gravity, then more gravity in the cold of space would redshift it even more? If so, then perhaps the universe is really not expanding, just appears to do so.

Cheers.
__________________
Caveat Lector. Experimentum summus judex...
  #2 (permalink)  
Old 23-February-2004, 05:41 PM
Cougar's Avatar
Cougar Cougar is online now
Order of Kilopi
 
Join Date: Aug 2003
Location: The Wild West
Posts: 4,819
Default Re: Dark Matter & Quantum Gravity

Quote:
Originally Posted by Lunatik
A much simpler way to understand gravity at a great distance from us would be to postulate that it is not a flat universal constant...
I don't see how you can imagine that this would be "simpler". Certainly the simplest solution has the gravitational constant the same everywhere. This has the added benefit that it appears to be consistent with reality.
__________________
Everyone is entitled to his own opinion, but not his own facts.
  #3 (permalink)  
Old 23-February-2004, 06:16 PM
soupdragon2 soupdragon2 is offline
Established Member
 
Join Date: Jan 2004
Location: London
Posts: 1,078
Send a message via MSN to soupdragon2
Default

Quote:
The articles are very interesting, but the authors leave us with an impression that what we think we understand is somehow incomplete.
My italics.

Funny. This thought hadn't even began to speculate about the merest possibility of crossing my mind. :wink:

Interesting concept, nonetheless, 'variable-constants'.



Everything should be made as simple as possible, but not simpler. Einstein
  #4 (permalink)  
Old 23-February-2004, 07:19 PM
ExpErdMann ExpErdMann is offline
Established Member
 
Join Date: Jun 2003
Location: Ontario
Posts: 1,315
Default

Lunatik, you might want to look at Toivo Jaakkola's work. He proposed that G changes somewhat in the manner you say. He links it all to a gravitational mechanism which is tied in with various redshift effects. One of his best papers is this one from Apeiron:

http://redshift.vif.com/JournalFiles...F/V03N3JAA.PDF

On p. 11 he mentions that the local value for G is one tenth of the value we would find in space well outside the solar system.
  #5 (permalink)  
Old 24-February-2004, 01:45 AM
Lunatik Lunatik is offline
Established Member
 
Join Date: Feb 2004
Location: California, USA
Posts: 555
Default

8) Thanks for the reference to Jaakkola's paper, will look into it. I had doodled on this concept of a 'variable-constant' gravity on other forums, Humancafe: http://www.humancafe.com/discus/messages/70/122.html , and also on the Space-Talk forum: http://www.space-talk.com/ForumE/sho...p;pagenumber=1 (Coppernicus2), where I explored possibilities of gravity being other than as now understood. Got a lot of flack for it, though. Hadn't thought of it as complicating things until now, that a variable-gravity constant, no matter its reason, does make for more difficult calculations in estimating mass of distant bodies, given their orbital behavior. Still, if the Pioneer 10 & 11 distant spacecrafts are slowing for reasons other than space dust of the Kuiper belt, as suggested by: http://www.space-talk.com/ForumE/sho...?threadid=2272 , (see post of 2/23/03), where Paul Marmet's paper is referenced, then "Nasa, we have a problem."

If it is not low density space dust acting on the Pioneers, then perhaps a new physics is in the offing. The idea that gravity redshifts electromagnetic waves passing through it is not new, and may account for the signal reaching us giving the appearance of slowing down. However, this could be hand in glove with the idea that gravity away from the inner solar region grows stronger, giving mass greater inertia, while at the same time redshifting the light reaching us. In effect, they may be two sides of the same thing. Anderson et al, the LANL team who first calculated the receding spacecrafts lagging acceleration, at present do not have an answer to this enigma, to my knowledge. Possible other clues that gravity ain't all the same everywhere?
:P
__________________
Caveat Lector. Experimentum summus judex...
  #6 (permalink)  
Old 25-February-2004, 01:08 AM
ExpErdMann ExpErdMann is offline
Established Member
 
Join Date: Jun 2003
Location: Ontario
Posts: 1,315
Default

I'm skeptical that a decrease in G as you move away from the Sun could be the reason for the Pioneer/Ulysses phenomenon. If mass distribution in the solar system were affecting G, then one would expect G to increase progressively as you get farther away from the Sun. The Pioneer/Ulysses data can be interpreted as a constant acceleration of the spacecraft, which would be consistent with a single step increase in G.
  #7 (permalink)  
Old 25-February-2004, 05:33 AM
Celestial Mechanic's Avatar
Celestial Mechanic Celestial Mechanic is offline
Order of Kilopi
 
Join Date: Jun 2002
Location: Milwaukee, WI
Posts: 4,543
Default

Quote:
Originally Posted by ExpErdMann
Lunatik, you might want to look at Toivo Jaakkola's work. [Snip!] One of his best papers is this one from Apeiron:

http://redshift.vif.com/JournalFiles...F/V03N3JAA.PDF
[Snip!]
If that's one of his best papers, I don't want to see his worst. He lost me with this paragraph:
Quote:
Originally Posted by Toivo Jaakkola
The famous Hafele-Keating (1972) experiment carried atomic clocks in aircrafts, [sic] and is claimed to support the special relativity prediction that moving clocks are slowed. However, the west-bound clock actually moved faster than the clock in the laboratory. In SR, the change of the time-rate cannot be dependent on direction.
The surface of the Earth is not an inertial frame; also, because the aircraft are flying at an altitude of several kilometers general relativistic effects are about the same order of magnitude as the special relativistic effects and cannot be ignored. All three clocks partake of the Earth's rotation, so the eastbound clock is slower than the Earthbound clock which is slower than the westbound clock. In addition, the two clocks in the air pick up some time because of the change in the gravitational potential.

For an entertaining (well, I think so!) and elementary calculation of a similar experiment, have a look at my "CM's Angels Return" posts in the "Twin Paradox: Definitive Proof That it's SR" thread.
__________________
Microsoft is over if you want it.

The bar has been lowered for the promotion of ATM ideas; the bar for the acceptance of ATM ideas must remain high.
  #8 (permalink)  
Old 26-February-2004, 01:53 AM
ExpErdMann ExpErdMann is offline
Established Member
 
Join Date: Jun 2003
Location: Ontario
Posts: 1,315
Default

Glad to hear you're reading up on Jaakkola. That paper is a useful primer to alternative viewpoints in physics and astronomy.

Your description of the Hafele-Keating experiment seems to back up just the point that Jaakkola was making. Suppose we have a non-rotating reference frame centred on the centre of the Earth. In that frame the 'stationary' clock on the Earth's surface is moving slower than the eastbound clock, but faster than the westbound clock. In that frame we would therefore expect to see the eastbound clock lose time relative to the stationary clock, while the westbound clock gains time relative to the other two. But according to SR we could just as easily choose the eastbound plane as our frame of reference, and in that frame it would be the other two clocks which lose time. That is why a Lorentzian interpretation of relativity is to be preferred over SR. In Lorentzian Relativity (LR) the motions of bodies and light take place in a preferred frame, which we would identify with a medium of some kind.

LR eliminates the paradox from the twins paradox. Your suggestions relating to GR and the Earth's not being an inertial frame do not change the picture. We could in principle set the stationary clock in a balloon at the same altitude as the planes, and run the experiment for a short time such that the Earth's curvature is not involved. The results would be the same, I think.

The same considerations are involved in the GPS. As Tom Van Flandern has emphasized, it is only necessary to make corrections to the clocks at the beginning to adjust for the time dilation effects arising from their different velocities and altitudes. The GPS clocks will then be synchronized from then on. The relative trajectories of the GPS satellites do not enter in.
  #9 (permalink)  
Old 26-February-2004, 03:44 AM
Lunatik Lunatik is offline
Established Member
 
Join Date: Feb 2004
Location: California, USA
Posts: 555
Default

ExpErdMann,

I've read through most of Jaakkola's paper, and found it excellent. Thanks so much for the reference, for it is refreshing to see a clear thinking mind express succinctly what many had attempted to challenge of GR/SR without success. Before I ventured into this arena, I had no ideas physicists could be so vindictive when presented with new ideas. Oh, the knife fights I've seen!

I'm also familiar with van Flandern's work, mostly discredited by the physics community, though in my opinion wrongly so. I am not a physicist, so my approach to the discipline is from that of a free thinker, with enough knowledge to be dangerous, but there are such glaring irregularities in modern physics that they beg attention. For example, the atomic clocks' slowing may as much be a function of redshifting while traveling through gravitational fields, same as light does, and vice versa speeding up in the other direction. There should be no mystery there, time is not what is slowing down if a clock slows, merely that the atomic oscillations are slowing. I would think if all my clocks at home suddenly slowed, I would not conclude that time, really a manmade notch on a stick, is slowing either. :P

Here is evidence of light redshifting without having to default to a Dopplershift expanding universe: http://www.space.com/scienceastronom...ar_010111.html

Light redshifts when it comes through great gravity fields. And if so, then Jaakkola may be right on.
__________________
Caveat Lector. Experimentum summus judex...
  #10 (permalink)  
Old 26-February-2004, 09:13 AM
Ari Jokimaki Ari Jokimaki is offline
Established Member
 
Join Date: Oct 2003
Location: Finland
Posts: 1,346
Default

Quote:
Originally Posted by Lunatik
Light redshifts when it comes through great gravity fields. And if so, then Jaakkola may be right on.
I don't think that gravitational redshifting can be used against the mainstream, because mainstream accepts it already (at least I'm under that impression).
  #11 (permalink)  
Old 26-February-2004, 09:32 AM
John Kierein John Kierein is offline
Established Member
 
Join Date: Dec 2001
Posts: 1,851
Default

redshifts don't happen when light goes through big gravity fields; even theoretically. The gravitational redshift occurs theoretically when light goes from a high gravity field to a low one, not when passing through. If it passes through, it blue shifts on the way in and then red shifts on the way out resulting in no red shift.
  #12 (permalink)  
Old 26-February-2004, 02:44 PM
Taibak Taibak is offline
Established Member
 
Join Date: Jan 2004
Posts: 504
Default

Quote:
Originally Posted by John Kierein
redshifts don't happen when light goes through big gravity fields; even theoretically. The gravitational redshift occurs theoretically when light goes from a high gravity field to a low one, not when passing through. If it passes through, it blue shifts on the way in and then red shifts on the way out resulting in no red shift.
And taking this a step further, the signals from the Pioneer spacecraft should be blueshifted when we receive them because they're moving into a stronger gravity field.
  #13 (permalink)  
Old 26-February-2004, 03:33 PM
ExpErdMann ExpErdMann is offline
Established Member
 
Join Date: Jun 2003
Location: Ontario
Posts: 1,315
Default

Quote:
Originally Posted by Lunatik
I've read through most of Jaakkola's paper, and found it excellent. Thanks so much for the reference, for it is refreshing to see a clear thinking mind express succinctly what many had attempted to challenge of GR/SR without success. Before I ventured into this arena, I had no ideas physicists could be so vindictive when presented with new ideas. Oh, the knife fights I've seen!
The sad thing about Jaakkola's paper is that it was his last one. He died shortly after writing it. I think if Jaakkola was still here he would have solved a lot of the puzzles out there now, such as "dark matter". His whole scientific career was spent fighting the mainstream. By the way, you might find the past issues of Apeiron interesting. You can access them online and you can purchase the whole archive of print issues from Apeiron for $75 - a real bargain! http://redshift.vif.com/journal_archives.htm

Quote:
I am not a physicist, so my approach to the discipline is from that of a free thinker, with enough knowledge to be dangerous, but there are such glaring irregularities in modern physics that they beg attention.
Being a trained physicist is not essential to making breakthroughs in physics. In fact modern physics training is probably retarding progress in some respects. But in the end you need to ground your insights in solid physical reasoning. Modern physics ran into trouble by basing too much on math.

Quote:
Light redshifts when it comes through great gravity fields. And if so, then Jaakkola may be right on.
Just for clarity, Jaakkola thought that light was redshifted as it passed through fields of matter, eg galaxies. In this respect it would be similar to the attenuation of gravity in passing through bodies, in Le Sage or Majorana-type gravity. Jaakkola linked these two 'redshifts' together.
  #14 (permalink)  
Old 27-February-2004, 04:53 AM
Celestial Mechanic's Avatar
Celestial Mechanic Celestial Mechanic is offline
Order of Kilopi
 
Join Date: Jun 2002
Location: Milwaukee, WI
Posts: 4,543
Default

I said the following once, it's worth saying it again:

I have one main problem with "pushing gravity": it is about the wrong geometry. Pushing gravity is ultimately about particle cross-sections. In contrast, general relativity is about geodesics in curved spacetime.

Pushing gravity holds that space is filled with as yet undetected particles that are transmitting their momentum to ordinary matter. We are not pulled towards the surface of the Earth but pushed there because the Earth shields us from the momentum flux moving in our local "up" direction.

We do not become weightless when we go indoors; the roof over our heads is not strong enough to pull us up (Newtonian gravity) or shield us from the downward momentum flux (pushing gravity). Another observation is that naively we expect that the Sun and Moon should be equally effective at shielding us from gravity since their apparent sizes are the same and thus that the pull of the Sun and Moon on the Earth should be equal. Celestial mechanics shows us that this is not so. Instead the force is proportional to the product of the masses, as measured in countless Cavendish-type experiments.

In fact, pushing gravity just cannot account for the fact that the gravity of a nucleus is proportional to the mass of the nucleus within one part in 10^12 or so. If A is the number of nucleons in a nucleus, the radius is known to be proportional to the cube root of A and the cross-sectional area is proportional to A^(2/3), while the mass is roughly proportional to A.

In brief, pushing gravity cannot account for the equivalence principle which has been observed to be true to a high degree of precision.
__________________
Microsoft is over if you want it.

The bar has been lowered for the promotion of ATM ideas; the bar for the acceptance of ATM ideas must remain high.
  #15 (permalink)  
Old 27-February-2004, 04:57 AM
Celestial Mechanic's Avatar
Celestial Mechanic Celestial Mechanic is offline
Order of Kilopi
 
Join Date: Jun 2002
Location: Milwaukee, WI
Posts: 4,543
Default

Another problem that I have with Jaakola's paper is this: in section 5i of the paper he derives the force law by taking the change in momentum of body 1, S_1, to be eta_2 * m_1 * A_2 / (2*pi) and the change in momentum of body 2 to be the same with subscripts 1 and 2 interchanged. Here eta_i denotes a measure of absorption, m_i the mass, and A_i/(2*pi) the fraction of the sky subtended at the other body by the i-th body. Jaakola then makes the leap of setting eta_i equal to G * m_1 / R_1^2, that is, equal to the surface gravity. The problem is that Jaakola is assuming the result from Newtonian gravity, not arguing from a consistent application of first principles of pushing gravity. In other words, he arrives at the Newtonian result for the force between two bodies by assuming the Newtonian result for surface gravity of a body.

If pushing gravity were really valid the surface gravity would be the same whether I'm standing on Earth, the Moon, or Phobos. Half of the sky is blocked off by the body below my feet. If you argue that I should be considering each nucleus in the body to be blocking some area and subtract the resulting sum of blocked momentum flux, you are still not going to get a result proportional to the mass divided by the radius squared. The cross-sections of the individual nuclei are proportional to the 2/3 power of the number of nucleons while the mass is proportional to the number of nucleons.

Pushing gravity is a geometric theory of gravity, a seductively simple idea, simple enough for the mathematically-challenged to understand it. Unfortunately it is the wrong geometry. Sorry, there is no royal road.
__________________
Microsoft is over if you want it.

The bar has been lowered for the promotion of ATM ideas; the bar for the acceptance of ATM ideas must remain high.
  #16 (permalink)  
Old 27-February-2004, 06:50 AM
Lunatik Lunatik is offline
Established Member
 
Join Date: Feb 2004
Location: California, USA
Posts: 555
Default

Hmm... I must admit that the redshift of light through gravity is still something of a mystery to me. It appears that light can redshift in a strong gravitational field, whether blue and red redshifting alternately as mentioned above, or simply a function of what happens to electromagnetic wavelengths in that environment.

Here is an example of light redshift taking place in the vicinity of neutron stars and black holes (as posted earlier above):
http://www.space.com/scienceastronom...ar_010111.html

What intrigues me in these X-ray images is that light redshifts as it enters the very great gravity region, with no evidence of blueshift. Since I am still reading Jaakkola's paper, still do not understand this completely yet. Also, I too am not comfortable with "push gravity" conceptually. In my mind's eye, gravity is what is left over, a kind of remainder force, from how the atom is modified by electromagnetic energy, so where there is much energy, such as near a hot star, gravity would tend to be very low per mass; vice versa, where there is a dearth of energy, such as far out in space far from any galaxy, gravity per mass should be much greater, giving mass out there tremendous inertia. (This was the thrust of my original post above. ) Not knowing more, these remain merely conjectural, but there may be some evidence that the postulated (and unobserved) Dark Matter is no more than this deep space gravity effect, where all atoms and molecules there experience a much greater gravity per mass.

I too regret Jaakkola's passing, since he seemed to be closing in on something of value. If gravity is indeed a 'variable-constant', then there is much future work to be done in physics, especially astrophysics, I would think.

Regarding how lightshift goes from high gravity to low gravity may account for why light 'bends' around massive bodies, especially solar bodies and galaxies, which are energy rich. Note that the resulting images from gravity lensing do not give us an inverted image, as would happen if gravity was truly a lens, but give us dual images, or halo images, as would happen if light blue and redshifts as had been described. I only bring this up as a point worth considering, though do not have a definitive answer on how this gravity lensing works.
:-?
__________________
Caveat Lector. Experimentum summus judex...
  #17 (permalink)  
Old 27-February-2004, 03:28 PM
ExpErdMann ExpErdMann is offline
Established Member
 
Join Date: Jun 2003
Location: Ontario
Posts: 1,315
Default

Quote:
Originally Posted by Celestial Mechanic
I have one main problem with "pushing gravity": it is about the wrong geometry. Pushing gravity is ultimately about particle cross-sections. In contrast, general relativity is about geodesics in curved spacetime.

Pushing gravity holds that space is filled with as yet undetected particles that are transmitting their momentum to ordinary matter. We are not pulled towards the surface of the Earth but pushed there because the Earth shields us from the momentum flux moving in our local "up" direction.
You have some things right about pushing gravity, but not others. PG does not challenge GR in the sense that GR gives the best description of how bodies move under gravitation. The curved spacetime idea works well enough for those who understand it. But GR offers no explanation at all of how gravity works - it is just a sort of mathematical structure. Consequently, it can offer useful predictions only on the basis of its (rather complex) equations rather than from a more physical understanding.

Pushing gravity can generate Newton's law at least, as has been shown countless times. So far no one has been able to add the GR 'correction' to the models, such that GR is regenerated. However, one can easily conceptualize a PG frame of reference analogous to an accelerating frame by considering frames of reference in which the flux of particles or waves is the same from all directions. Such frames would be seen to be moving ('falling') towards gravitating bodies. From this consideration I suppose that a GR variant for pushing gravity can be constructed, but so far it hasn't been done. That could be because GR makes just minor corrections to Newtonian gravity, and so is rarely used in ordinary physics. It will be sort of the 'icing on the cake' when PG is shown to be fully compatible with GR. And remember, Einstein was not opposed to the existence of a gravitational medium.

Quote:
We do not become weightless when we go indoors; the roof over our heads is not strong enough to pull us up (Newtonian gravity) or shield us from the downward momentum flux (pushing gravity). Another observation is that naively we expect that the Sun and Moon should be equally effective at shielding us from gravity since their apparent sizes are the same and thus that the pull of the Sun and Moon on the Earth should be equal. Celestial mechanics shows us that this is not so. Instead the force is proportional to the product of the masses, as measured in countless Cavendish-type experiments.
I think here you are missing the point that the absorption coefficient of atoms to the Le Sage flux is extremely small. Some Le Sagians have liknened the particles to neutrinos (some even say thay are neutrinos, but this seems wrong to me). It is only in the case of very large bodies, like 'black holes' for instance, where an appreciable fraction of the incident flux is absorbed.

Quote:
In fact, pushing gravity just cannot account for the fact that the gravity of a nucleus is proportional to the mass of the nucleus within one part in 10^12 or so. If A is the number of nucleons in a nucleus, the radius is known to be proportional to the cube root of A and the cross-sectional area is proportional to A^(2/3), while the mass is roughly proportional to A.

In brief, pushing gravity cannot account for the equivalence principle which has been observed to be true to a high degree of precision.
In this case you are omitting consideration of the nature of the strong nuclear force. In a fully developed Le Sage scheme, all the forces would be seen to have a common origin. A number of Le Sage-type models have been done to mimic the strong force. Qualitatively, you can see that the mass per nucleon decreases as you add nucleons up to Fe - the mass defect. This is expected in PG since the nucleons would indeed screen each other slightly as you build up to larger nuclei. The strong force would thus be some sort of short range analogue to PG.
  #18 (permalink)  
Old 27-February-2004, 03:48 PM
milli360's Avatar
milli360 milli360 is offline
Established Member
 
Join Date: Dec 2003
Location: NC, USA
Posts: 2,464
Default

Quote:
Originally Posted by ExpErdMann
And remember, Einstein was not opposed to the existence of a gravitational medium.
OK, but he only gets one vote.
  #19 (permalink)  
Old 27-February-2004, 05:32 PM
Tensor Tensor is offline
Order of Kilopi
 
Join Date: Nov 2002
Location: Sarasota Fl
Posts: 3,687
Default

Quote:
Originally Posted by ExpErdMann
I think here you are missing the point that the absorption coefficient of atoms to the Le Sage flux is extremely small. Some Le Sagians have liknened the particles to neutrinos (some even say thay are neutrinos, but this seems wrong to me). It is only in the case of very large bodies, like 'black holes' for instance, where an appreciable fraction of the incident flux is absorbed.
ExpErdMann, could you clarify this for me? Mass wise, BH can be as small as three to eight solar masses, which really isn't "large" compared to the galaxy the star is in. And BH are quite small, volume wise, compared to their original star. From your comment above, a star on the main sequence, with a diameter of approximately 3 million km, should absorb much more than the approximately 13 km BH that star would form. After all, there is more volume to do the absorbtion. It seems to me that this would give you a different amount of gravity at the different stages of a stars life, depending on it's volume.
__________________
Some try to tell me, thoughts they cannot defend,... - Moody Blues.

Neptune- The original Dark Matter.

The author feels that this technique of deliberately lying will actually make it easier for you to learn the ideas. - Donald Knuth
  #20 (permalink)  
Old 27-February-2004, 07:06 PM
ExpErdMann ExpErdMann is offline
Established Member
 
Join Date: Jun 2003
Location: Ontario
Posts: 1,315
Default

Quote:
Originally Posted by Celestial Mechanic
The problem is that Jaakola is assuming the result from Newtonian gravity, not arguing from a consistent application of first principles of pushing gravity. In other words, he arrives at the Newtonian result for the force between two bodies by assuming the Newtonian result for surface gravity of a body.
You're right. Jaakkola was not attempting a full derivation here. I think his equations were a sort of preliminary attempt at developing a Le Sage-type theory. We never got to see his final work.
  #21 (permalink)  
Old 27-February-2004, 08:24 PM
ExpErdMann ExpErdMann is offline
Established Member
 
Join Date: Jun 2003
Location: Ontario
Posts: 1,315
Default

Quote:
Originally Posted by Lunatik
Hmm... I must admit that the redshift of light through gravity is still something of a mystery to me. It appears that light can redshift in a strong gravitational field, whether blue and red redshifting alternately as mentioned above, or simply a function of what happens to electromagnetic wavelengths in that environment.

Here is an example of light redshift taking place in the vicinity of neutron stars and black holes (as posted earlier above):
http://www.space.com/scienceastronom...ar_010111.html

What intrigues me in these X-ray images is that light redshifts as it enters the very great gravity region, with no evidence of blueshift.
From your link, they tell us that as gas is drawn in towards these large objects, the light emitted by that gas is redshifted because it is being emitted from a deeper gravitational well. You won't see any blueshift in this case unless you as observer were situated even closer in to the object than the gas.

Quote:
Not knowing more, these remain merely conjectural, but there may be some evidence that the postulated (and unobserved) Dark Matter is no more than this deep space gravity effect, where all atoms and molecules there experience a much greater gravity per mass.
There could be something to what you say, but once again I would tend to see the increase of G as you move out into space to be a likely consequence of absorption of gravitational flux by the Sun and planets.

Quote:
I too regret Jaakkola's passing, since he seemed to be closing in on something of value. If gravity is indeed a 'variable-constant', then there is much future work to be done in physics, especially astrophysics, I would think.
You bet!
  #22 (permalink)  
Old 27-February-2004, 08:46 PM
ExpErdMann ExpErdMann is offline
Established Member
 
Join Date: Jun 2003
Location: Ontario
Posts: 1,315
Default

Quote:
Originally Posted by Tensor
ExpErdMann, could you clarify this for me? Mass wise, BH can be as small as three to eight solar masses, which really isn't "large" compared to the galaxy the star is in. And BH are quite small, volume wise, compared to their original star. From your comment above, a star on the main sequence, with a diameter of approximately 3 million km, should absorb much more than the approximately 13 km BH that star would form. After all, there is more volume to do the absorbtion. It seems to me that this would give you a different amount of gravity at the different stages of a stars life, depending on it's volume.
You've got this right, Tensor. In a Le Sage-type model (at least some of them), there is a distinction between a body's 'true mass' (the mass it would have if its constituents were finely divided and widely distributed in space) and its 'apparent mass' (the mass we actually observe). Much of the work on this point came out in Quirino Majorana's studies on gravitational absorption in the early 1900's. (Majorana's theory was different, but that's another story). For bodies not too large it turns out that the apparent mass of a body is related approximately to the true mass M by

Mapp = M (1- h d l ) ,

where h is the absorption coefficient, d is the density and l is the radius. From this one finds for instance that the Jupiter's apparent mass is only about 95 % of its true mass. Now as a star moves through different stages it should show different apparent masses, as you suggest. But it is important to remember that at a certain size, bodies will absorb almost the whole flux, and at this point the gravitational force is related to their cross-sectional area only.

One could object, as the astronomer H.N. Russell did, that the solar system would become chaotic if the gravitational masses of the planets deviated from their inertial ones. However, it can be posited that the inertial masses change in tandem with the gravitational masses.

Incidentally, this topic is covered well in the recent book "Pushing Gravity", in papers by Radzievskii and Kagalnikova and by Roberto Martins.
  #23 (permalink)  
Old 28-February-2004, 04:17 AM
Lunatik Lunatik is offline
Established Member
 
Join Date: Feb 2004
Location: California, USA
Posts: 555
Default

ExpErdMann, and all,
Quote:
From your link, they tell us that as gas is drawn in towards these large objects, the light emitted by that gas is redshifted because it is being emitted from a deeper gravitational well. You won't see any blueshift in this case unless you as observer were situated even closer in to the object than the gas.

There could be something to what you say, but once again I would tend to see the increase of G as you move out into space to be a likely consequence of absorption of gravitational flux by the Sun and planets.
Yes, I can see what you mean, and in the image the red appears extreme. If this same principle is applied to light reaching Earth, and the Sun's energy rich heliosphere, from the great distances of 'cold' space, then we should witness a similar redshift, which of course we do. This does not disprove an expanding universe, but it certainly puts it in doubt.

I had gone back through Jaakkola's paper, specifically item 5.1 "The 2-body Problem", and see how the 'impulse' space description of gravity is understood as a kind of 'screening' shadow created by massive bodies, so that the force from space 'pushes' on these bodies together. He is also quick to point out that this force acts in a Newton described inverse square law, 1/R^2, because we know this from experience. So a kind of 'shielding' takes place by matter, where the exhibited gravitational attraction is a function of the gravitons pushing on it.

I cannot help but think of this as a euphomism for the attractive force of gravity, another point of view, but not necessarily correct. In the same way nature abhors a vacuum, it also seems to abhor a void of mass, so that when two material bodies are in proximity, they will exhibit an attraction to fill that void. This is a subtle epistemological point, but it shifts the focus from push to pull, as I think it should. The reason I like pull better is because of the inertia factor, which tends to resist acceleration when force is applied, including gravitational force.

In the Haisch-Rueda paper, "Nature of Mass", at CalPhysics: http://calphysics.org/mass.html , there is a discussion of mass and ZPF, where they also invoke the deBroglie wavelength equation combined with Einstein's famous equation for energy: hc/L = mc^2.

It is theorized that gravity and inertia have an equivalence. In my view, if in the deep cold of space gravity is great, inertia should likewise be great. This would mean we would need more acceleration to move mass there, or so it would seem, certainly more than our rocket ships can provide... not an alien conspiracy theory!

As a curiosity, taking the equations I listed at the very beginning of this thread, where m = 1, is replaced with m = (1-g), something interesting happens at a very low frequency of light, where L = 3.97e-7 meters. So that:

hc/L(m) = mc^2 = (1-g)c^2, where h = Planck's, L= lambda, (m)= proton mass, 1.67e-27 kg. multiplier (to make equation balance out on both sides in kilograms), and g = proton gravitational constant (dimensionless times mass), where m is always m = 1, we get:

(6.626e-34)(3e8) / (3.97e-7)(1.67e-27) = (1-g)c^2 = E.

This is a curiosity, because the denominator cancells Planck's constant h, and thus we are left with:

3e8 Joules = (1-g)c^2, for which result we find that (1-g) = 1/c (approx.), since the resulting E = ~c Joules, or pc = E, where p =1, or momentum is at its lowerst level. Below that, it falls into fractions approaching zero, or a black hole. This 'cut-off' frequency, where p =1, and L = 3.97e-7 meters, may in fact be the gravity level of dark instellar space far from galaxies, or a kind of background space... only a thought.

This would also mean that if a star, or galaxy, was unable to generate electromagnetic energy above this 'cut off' energy, it would be extremely gravity dense, if this is so. Anyway, so much for 'Dark Matter', which is unobservable if it consists of merely deep space great gravity.

These are merely 'doodles' or thinking aloud, but they pose interesting possibilities. I like them better than the gravitational flux being absorbed by the sun and planets, or stars and galaxies idea, though it too bears watching for clues.

Too bad Jaakkola is not around to explore these some more...

RE
Quote:
For bodies not too large it turns out that the apparent mass of a body is related approximately to the true mass M by

Mapp = M (1- h d l ) ,

where h is the absorption coefficient, d is the density and l is the radius. From this one finds for instance that the Jupiter's apparent mass is only about 95 % of its true mass.
I too think the mass of more distant planets is 'apparently' understated, since we are using Newton's constant G to estimate their mass from their orbital velocities. Interesting that Mapp had already explored this a century ago... Did we get sidetracked somewhere with Einstein-Lorenz's relativity? We might have been in space earlier, perhaps, if we had understood variable inertial mass sooner. We're sort of there now, but barely.

One possible test for all this would be to find out if comets de-precess as they exit the solar system, something no one thinks they do at present. If it's all relative, where the inertial mass increases as it enters greater gravity, then all elliptic orbital motions would remain the same, except for velocity, where it should slow... I would think. 8)

Ps: We know there is a precessional acceleration for Mercury when it is at its perihelion, same as we know the Pioneer distant space craft appear to be slowing as they exit the solar system. This may be a clue that at their aphelion, the comets which have very large elliptical orbits may likewise slowdown, while speeding up at their perihelion. I think this could be an important clue.
__________________
Caveat Lector. Experimentum summus judex...
  #24 (permalink)  
Old 28-February-2004, 06:07 AM
Celestial Mechanic's Avatar
Celestial Mechanic Celestial Mechanic is offline
Order of Kilopi
 
Join Date: Jun 2002
Location: Milwaukee, WI
Posts: 4,543
Default

Quote:
Originally Posted by ExpErdMann
[Snip!]You have some things right about pushing gravity, but not others. PG does not challenge GR in the sense that GR gives the best description of how bodies move under gravitation. The curved spacetime idea works well enough for those who understand it. But GR offers no explanation at all of how gravity works - it is just a sort of mathematical structure. Consequently, it can offer useful predictions only on the basis of its (rather complex) equations rather than from a more physical understanding.
I'm disturbed by the attitude displayed here, which seems to be, "I can't understand it so it can't be right even if it gives results that agree with the experiments." This is so contrary to the way science is done. The mathematics didn't exist in Newton's time so he invented it. Einstein recognized that he needed to understand tensor analysis and Riemannian geometry so learned it. Maybe you should try to learn the math necessary for GR. Gravitation by Misner, Thorne, and Wheeler is a good place to start.

Quote:
Originally Posted by Celestial Mechanic
In fact, pushing gravity just cannot account for the fact that the gravity of a nucleus is proportional to the mass of the nucleus within one part in 10^12 or so. If A is the number of nucleons in a nucleus, the radius is known to be proportional to the cube root of A and the cross-sectional area is proportional to A^(2/3), while the mass is roughly proportional to A. In brief, pushing gravity cannot account for the equivalence principle which has been observed to be true to a high degree of precision.
Quote:
Originally Posted by ExpErdMann
In this case you are omitting consideration of the nature of the strong nuclear force. In a fully developed Le Sage scheme, all the forces would be seen to have a common origin. A number of Le Sage-type models have been done to mimic the strong force. Qualitatively, you can see that the mass per nucleon decreases as you add nucleons up to Fe - the mass defect. This is expected in PG since the nucleons would indeed screen each other slightly as you build up to larger nuclei. The strong force would thus be some sort of short range analogue to PG.
The binding energy is much smaller in magnitude than the shielding that would exist based on the fact that A nucleons occupy a volume proportional to A and hence have a cross-section proportional to A^(2/3). This means that a nucleus of Aluminum-27 has a cross-sectional area only 9 times greater than that of a single nucleon, not 27 times minus a little bit of binding energy. In fact, instead of shielding, there would have to be anti-shielding going on! Back to the drawing board!
__________________
Microsoft is over if you want it.

The bar has been lowered for the promotion of ATM ideas; the bar for the acceptance of ATM ideas must remain high.
  #25 (permalink)  
Old 28-February-2004, 03:04 PM
ExpErdMann ExpErdMann is offline
Established Member
 
Join Date: Jun 2003
Location: Ontario
Posts: 1,315
Default

Quote:
Originally Posted by Celestial Mechanic
Quote:
Originally Posted by ExpErdMann
But GR offers no explanation at all of how gravity works - it is just a sort of mathematical structure. Consequently, it can offer useful predictions only on the basis of its (rather complex) equations rather than from a more physical understanding.
I'm disturbed by the attitude displayed here, which seems to be, "I can't understand it so it can't be right even if it gives results that agree with the experiments." This is so contrary to the way science is done. The mathematics didn't exist in Newton's time so he invented it. Einstein recognized that he needed to understand tensor analysis and Riemannian geometry so learned it. Maybe you should try to learn the math necessary for GR. Gravitation by Misner, Thorne, and Wheeler is a good place to start.
Perhaps you could look more at the historical context. When Newton formed his gravitational laws, he also tried to provide possible mechanical causes of gravity, some of which were of the 'pushing gravity' mode. But by the time Le Sage proposed his theory a half century later, people were used to thinking of gravity without pondering its mechanical cause - so Le Sage was basically ignored. Jump ahead 100 years to the time of Maxwell and Kelvin. Physicists were using mechanical ether concepts again, and so Le Sage's theory had an upsurge again. But that was quickly squelched by Einstein and his GR, which was in essence just a mathematical formulation. The idea of spacetime curvature must be pleasant for the mathematicians, but no one can say it really explains gravity. It just gives us a formalism. Now in the last few decades, with increasing interest in the existence of background fields (zeropoint, 'dark matter', 'dark energy', etc) the idea of going back to Le Sage is coming back a bit. My general point is that the preference to look at gravity as a mathematical structure or a phenomenon with a real physical cause is a matter of taste. In some periods one style of thinking is preferred, in others the other style. For me there's no sense in trying to rely exclusively on the math of GR. It can give us some things but easily miss others.

Quote:
Originally Posted by Celestial Mechanic
In fact, pushing gravity just cannot account for the fact that the gravity of a nucleus is proportional to the mass of the nucleus within one part in 10^12 or so. If A is the number of nucleons in a nucleus, the radius is known to be proportional to the cube root of A and the cross-sectional area is proportional to A^(2/3), while the mass is roughly proportional to A. In brief, pushing gravity cannot account for the equivalence principle which has been observed to be true to a high degree of precision.
Again you are overlooking that the absorption coefficient of nucleons can in theory be made as low as we want. The nucleons within a nucleus may scarcely shield each other at all, just as intranuclear shielding is negligible for neutrino interactions with matter.

Quote:
The binding energy is much smaller in magnitude than the shielding that would exist based on the fact that A nucleons occupy a volume proportional to A and hence have a cross-section proportional to A^(2/3). This means that a nucleus of Aluminum-27 has a cross-sectional area only 9 times greater than that of a single nucleon, not 27 times minus a little bit of binding energy. In fact, instead of shielding, there would have to be anti-shielding going on!
Again you are simply using the cross-section of nuclei as it has been measured with other forms of radiation. It need not be the same cross-section for the Le Sage radiation.

Quote:
Back to the drawing board!
Hey, I live at the drawing board!
  #26 (permalink)  
Old 28-February-2004, 03:38 PM
milli360's Avatar
milli360 milli360 is offline
Established Member
 
Join Date: Dec 2003
Location: NC, USA
Posts: 2,464
Default

Quote:
Originally Posted by ExpErdMann
Physicists were using mechanical ether concepts again, and so Le Sage's theory had an upsurge again. But that was quickly squelched by Einstein and his GR, which was in essence just a mathematical formulation. The idea of spacetime curvature must be pleasant for the mathematicians, but no one can say it really explains gravity.
You're not seriously suggesting that Le Sage's theory "explains" gravity, are you? It wouldn't give us an insight into the basic why's any more than Einstein's would.
  #27 (permalink)  
Old 28-February-2004, 05:19 PM
Lunatik Lunatik is offline
Established Member
 
Join Date: Feb 2004
Location: California, USA
Posts: 555
Default

Celestial Mechanic, very much enjoyed your reference above to "CM Angels Return", http://www.badastronomy.com/phpBB/vi...=199050#199050
Quote:
Phew! That's as far into GR as we need to go! If we set M equal to 0 we would get:

c^2 * dT^2 = c^2*dt^2 - dr^2 - r^2*dtheta^2 - r^2*sin^2(theta)*dphi^2,

which is just the Minkowski metric transformed to spherical coordinates. GR extends SR into new domains just as SR extends Newtonian physics.

If we divide Equation 1 through by c^2*dt^2 we get: (dT/dt)^2 = 1 - 2*G*M/r/c^2 - r^2*sin^2(theta)*(dphi/dt)^2/c^2.

All quantities other than the 1 on the right side are small quantities of the first order, so taking the square root to first order we have:

(dT/dt) = 1 - G*M/r/c^2 - (1/2)*r^2*sin^2(theta)*(dphi/dt)^2/c^2.
... okay, cool...

Then in part 3, you say:
Quote:
Anne and Charlotte are cruising at an altitude of h = 10 km, so for them 1/r =1/(R+h) = (1/R)-(h/R^2) to the first order in small quantities. Since Anne is traveling eastward at v = 250 m/s (900 km/hr), her total velocity along the circle of latitude is V+v. Since Charlotte travels westward, her velocity along the circle of latitude is V-v.
...
Anne's clock runs slow compared to Barbara's by a factor of 1 + (1.09 - 0.35 -0.90)*10^-12 = 1 - 0.16*10^-12.
Charlotte's clock runs fast compared to Barbara's by a factor of 1 + (1.09 - 0.35 + 0.90)*10^-12 = 1 + 1.64*10^-12.
From what I understand, Cesium-133 clocks will either "redshift or blueshift" depending upon their direction. Is this what the V+v and V-v refer to, their lightshift directions? Could there be a "lightshift to atomic oscillations" relationship here?

The math seems to bear this out... but is it proof positive that "Time" actually is changing? Or is it merely a calculation illustrating why the atomic oscillations will red/blue shift?

I can't claim to understand this GR/SR stuff completely, though I know it somewhat. But I also like to cut to the quick and find what's real. Though math may be elegant, it can sometimes be true only in terms of itself, and not necessarily express what is happening. Chaotic results can flow from very small discrepancies in how numbers work, especially at very small micro values, since we are using digital to express analog, and the two don't always match up. Not to disparage your very fine example, but do you see where I'm coming from?

Gravity is known to red/blue shift light, so this must be taken into consideration, I would think. [-X
__________________
Caveat Lector. Experimentum summus judex...
  #28 (permalink)  
Old 28-February-2004, 09:58 PM
ExpErdMann ExpErdMann is offline
Established Member
 
Join Date: Jun 2003
Location: Ontario
Posts: 1,315
Default

Quote:
Originally Posted by milli360
Quote:
Originally Posted by ExpErdMann
Physicists were using mechanical ether concepts again, and so Le Sage's theory had an upsurge again. But that was quickly squelched by Einstein and his GR, which was in essence just a mathematical formulation. The idea of spacetime curvature must be pleasant for the mathematicians, but no one can say it really explains gravity.
You're not seriously suggesting that Le Sage's theory "explains" gravity, are you? It wouldn't give us an insight into the basic why's any more than Einstein's would.
I'm not sure I'm catching your drift. If you're saying we might not ever be able to understand what EM radiation is or what gravitons are, even in Le Sage's theory, then that could be true. But even though we may not ever be able to understand what the ultimate entities are, we may still be able to see how they interact with matter to cause gravity and inertia.
  #29 (permalink)  
Old 29-February-2004, 05:34 AM
Celestial Mechanic's Avatar
Celestial Mechanic Celestial Mechanic is offline
Order of Kilopi
 
Join Date: Jun 2002
Location: Milwaukee, WI
Posts: 4,543
Default

Quote:
Originally Posted by ExpErdMann
[Snip!]Perhaps you could look more at the historical context. When Newton formed his gravitational laws, he also tried to provide possible mechanical causes of gravity, some of which were of the 'pushing gravity' mode. But by the time Le Sage proposed his theory a half century later, people were used to thinking of gravity without pondering its mechanical cause - so Le Sage was basically ignored. Jump ahead 100 years to the time of Maxwell and Kelvin. Physicists were using mechanical ether concepts again, and so Le Sage's theory had an upsurge again. But that was quickly squelched by Einstein and his GR, which was in essence just a mathematical formulation. The idea of spacetime curvature must be pleasant for the mathematicians, but no one can say it really explains gravity. It just gives us a formalism.
Now you're starting to sound like the Creationists (oh, excuse me, I think now they're calling themselves "Intelligent Designers") who show up at school board meetings to object "but it's only a theory!". "... just a mathematical formulation.", "It just gives us a formalism." Yes it gives us a formalism, and the best one that we have, one that has been tested time and time again in experiment after experiment. All LeSage has given us is a bunch of hand-waving.
Quote:
Originally Posted by ExpErdMann
My general point is that the preference to look at gravity as a mathematical structure or a phenomenon with a real physical cause is a matter of taste. In some periods one style of thinking is preferred, in others the other style. For me there's no sense in trying to rely exclusively on the math of GR. It can give us some things but easily miss others.
And what, exactly does it miss?
Quote:
Originally Posted by ExpErdMann
[Snip!]Again you are simply using the cross-section of nuclei as it has been measured with other forms of radiation. It need not be the same cross-section for the Le Sage radiation.
So let me get this straight: somehow, there is a magical LeSage radiation cross section that is always proportional to the mass of the particle, however arrived at. If a nucleus is bound together resulting in a composite body somehow the cross section adjusts to be exactly equal to the mass of the composite. Is this what you're saying?

Contrast this with GR which says that spacetime curvature (in the form of the Einstein tensor) is proportional to the stress-energy tensor. That means that gravity couples to everything, masses of components and binding energy alike, resulting in the equivalence principle automatically. (Of course Einstein argued this in the opposite direction!)
__________________
Microsoft is over if you want it.

The bar has been lowered for the promotion of ATM ideas; the bar for the acceptance of ATM ideas must remain high.
  #30 (permalink)  
Old 29-February-2004, 11:17 AM
milli360's Avatar
milli360 milli360 is offline
Established Member
 
Join Date: Dec 2003
Location: NC, USA
Posts: 2,464
Default

Quote:
Originally Posted by ExpErdMann
Quote:
Originally Posted by milli360
Quote:
Originally Posted by ExpErdMann
Physicists were using mechanical ether concepts again, and so Le Sage's theory had an upsurge again. But that was quickly squelched by Einstein and his GR, which was in essence just a mathematical formulation. The idea of spacetime curvature must be pleasant for the mathematicians, but no one can say it really explains gravity.
You're not seriously suggesting that Le Sage's theory "explains" gravity, are you? It wouldn't give us an insight into the basic why's any more than Einstein's would.
I'm not sure I'm catching your drift. If you're saying we might not ever be able to understand what EM radiation is or what gravitons are, even in Le Sage's theory, then that could be true. But even though we may not ever be able to understand what the ultimate entities are, we may still be able to see how they interact with matter to cause gravity and inertia.
As opposed to interacting with spacetime to cause gravity and inertia?

You've just transferred the problem from one realm to another. I'm pointing out that your criticism of GR above, also applies to the theory that you are advocating.
Closed Thread


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT. The time now is 02:37 AM.


Powered by vBulletin® Version 3.8.3
Copyright ©2000 - 2009, Jelsoft Enterprises Ltd.
LinkBacks Enabled by vBSEO 3.0.0
©  2006 Bad Astronomy and Universe Today