modest Posted April 24, 2008 Report Share Posted April 24, 2008 Speaking of anti-gravity, Would a graviton be its own antiparticle? I guess like a photon all of its relevant quantum numbers would be zero meaning no anti-graviton. -modest Quote Link to comment Share on other sites More sharing options...
freeztar Posted April 24, 2008 Report Share Posted April 24, 2008 L1 (where gravity is cancelled: precisely to zero)But gravity is not really "cancelled" at L1. It's just that the combined gravitational forces (which are still present) equal close to zero. Quote Link to comment Share on other sites More sharing options...
freeztar Posted April 24, 2008 Report Share Posted April 24, 2008 Speaking of anti-gravity, Would a graviton be its own antiparticle? I guess like a photon all of its relevant quantum numbers would be zero meaning no anti-graviton. -modest Or maybe a graviton is an anti-photon. :confused: :hihi: Quote Link to comment Share on other sites More sharing options...
coldcreation Posted April 25, 2008 Author Report Share Posted April 25, 2008 But gravity is not really "cancelled" at L1. It's just that the combined gravitational forces (which are still present) equal close to zero. The gravitational field is cancelled at L1. So, The value of the field gradient is zero. That is why a test particle placed there will 'feel' no gravitational force (until it is displaced). Though L1 points are saddle points, they may or may not be the relative minima of the system. Other critical points may have higher or lower elevation in the potential of the system, but the field gravitational curvature gradient could still be zero. In sum, gravity - spacetime curvature - is really zero at L1 (relatively, since it is not the absolute zero value of gravitational potential - the value at infinity). There are some very informative papers written on this subject. Any one of them will do. I will link some in my next post for you and others (say, Little Bang) that might be interested. CC Quote Link to comment Share on other sites More sharing options...
HydrogenBond Posted April 25, 2008 Report Share Posted April 25, 2008 Here is a simple question. The EM and nuclear forces when they act will give off energy. What is the nature of the energy given off when the gravitational force acts? If we call it an attractive force when two separated masses get closer and lower potential energy, it should show energy output. Or, is gravity unique among forces, on recycle mode, placing that energy into the potential associated with GR? In other words, to create time dilation using SR we need to add energy. It would make sense that GR time dilation will also require energy, with that energy coming from energy recycle. Where GR and SR are the same is time dilation and distance contraction. Where they differ is only SR will generate relativistic mass increase onto the existing mass. Because of the two out of three similarities, does gravity generate relativistic mass? In this case, it would have to appear from matter instead of adding to it. The affect would be mass burn into mass-energy for virtual affects. In the limit, particle mass would not be able to exist, i.e., black hole, to maintain the proper relativistic mass ratio for than amount of space-time affect. Quote Link to comment Share on other sites More sharing options...
coldcreation Posted April 25, 2008 Author Report Share Posted April 25, 2008 . Let's see if the Lagrangian pattern discussed throughout this thread extends to galaxy clusters. Note the similarity of this image with the illustrations above (Original source): Here is another set of images representing the galaxy cluster MS0735.6 + 7421 (Chandra X-ray image (left) and optical image (right), superposed with radio contours. This system, too, is consistent with Lagrangian dynamics. The following cluster is interesting too: The original photo and article can be found here. The most distant X-ray cluster of galaxies yet has been found by astronomers using NASA's Chandra X-ray Observatory. Approximately 10 billion light years from Earth' date=' the cluster 3C294 is 40 percent farther than the next most distant X-ray galaxy cluster previously known. [...'] Chandra's image reveals an hourglass-shaped region of X-ray emission centered on the previously known central radio source and extends outward from the central galaxy for at least 600,000 light years. The presence of such this hot, gravitationally bound gas is evidence of a massive cluster. I will bet my lucky stars that the central radio source is sitting directly at the L1 saddle point (in halo orbital position). Note: these systems, unlike many of Arp's examples, are not thought to be chance alignments of background objects. i.e., they are associated according to the mainstream interpretation, yet they display many of the same geometric characteristics: a bright (active) central source flanked by objects lined up along an axis (and likely connected by luminous bridges). Here are a few more examples of galaxy clusters that display a similar pattern (from this source): This is one of my favorites, Abell 2218: Source: Morphologies and stellar populations of galaxies in the core of Abell 2218 This result' date=' together with the distributions of ages, metallicities and masses, indicates that E-type galaxies are more massive and have older stellar populations, while L-type galaxies are less massive and have a wider range of stellar Our results agree with a proposed two-step scenario for the evolution of galaxies in clusters. In addition, an extremely blue merging galaxy system is found at the core, with the nominal redshift of the cluster.[/quote'] Conclusion: Galaxy clusters, in addition to planetary systems, stellar systems and galaxies display a pattern typical of Lagrange dynamics. The L1 saddle point, though unstable, can (and does) provide the site for the collection of mass: usually a bright radio source, which likely formed as a halo orbiting massive cloud. Once it becomes massive enough stability is ensured since it develops its own gravitational potential well (flanked by new L1 points on either side, with large groupings of galaxies further out along the same line) Even though, the dynamics intrinsic to the object may remain chaotic, especially if it occupies a rectangular minima (more on this later). The pattern is M1 - L1 - M2 (and occasionally with galaxies occupying L4 and L5). CC Quote Link to comment Share on other sites More sharing options...
modest Posted April 25, 2008 Report Share Posted April 25, 2008 CC, Are there any examples or observations of something natural (not something human made) at a L1, L2, or L3 point? Has that ever been observed? -modest Quote Link to comment Share on other sites More sharing options...
Little Bang Posted April 25, 2008 Report Share Posted April 25, 2008 Wouldn't finding a natural object at a Le grange point be like balancing a pencil on it's point? Quote Link to comment Share on other sites More sharing options...
coldcreation Posted April 26, 2008 Author Report Share Posted April 26, 2008 CC, Are there any examples or observations of something natural (not something human made) at a L1, L2, or L3 point? Has that ever been observed? Fair question. I've already answer it above. The answer, at least with respect to the L1 point, is yes. I've also provided images of a large variety systems where the L1 point is occupied. After all, this is observational evidence. It could of course be argued that this claim, or interpretation of empirical evidence is false, e.g., that these are chance alignments of objects that, on the surface, mimic the M1, L1, M2 line. Terminology: By chance alignment it is meant that object known to be gravitationally associated appear lined up along the same axis (e.g., two massive clusters separated by, say, an active Seyfert galaxy or strong radio source located at the saddle point; between the two). It is not meant the chance alignment of background objects. However, a close inspection of the local extrema, the maximum and minimum of potentials, along with saddle point positions and other critical points of a system, It is straight forward to show that orbits can be (and are) attained or maintained around saddle point (notably around L1). The motion consists of regular invariant curves, closed topological circles around one rotating about one singular invariant Lagrangian point: L1. (Caranicolas, N. D., 2002, Connecting Global to Local Parameters in Barred Galaxy Models). See the following illustration, from the above reference (enhanced by Coldcreation). Caranicolas writes regarding this orbit in barred galaxy models: The corresponding orbits are box-orbits. Those forming the outer invariant curves belong to elongated boxes that support the bar while' date=' as we approach the “central” invariant point, the boxes become more rectangular. 3. Orbits in the local potential Furthermore, the local potential can be found by expanding the effective potential (3) in a Mc-Laurin series near the stable Lagrange point L1, which coincides with the origin. [...'] 4. Discussion [...] Furthermore, we must note that in the global model [describing global motion in a barred galaxy and the corresponding parameters of the local potential] the resonant orbits of type b as well as the chaotic orbits of type d carry stars in the central parts of the galaxy. Therefore we have an increasing density near L1. It is interesting to observe that a large number of high energy stars passing near L1 are in chaotic orbits. The other two types of orbits a and b do not contribute in the central density. Here the reader might respond: But this is only a model. What proof do we have that, in the real world, barred galaxies exhibit Lagrangian (and Hamiltonian) dynamics? Good question. The answer: this is the only compelling solution that explains the formation, existence and longevity of the bar structure. So, are there non-man-made objects observed to be located at, or orbiting around L1? Looking at the evidence (both quantitative and observational, some of which has been presented above), I would answer resoundingly yes. I will come back to barred galaxy structure and the relation to Lagrange dynamics in my next few posts. CC Quote Link to comment Share on other sites More sharing options...
Little Bang Posted April 26, 2008 Report Share Posted April 26, 2008 An interesting question for NASA. " Could you put a satellite at the moon earth Le Grange point and have it stay there for a million years? " Myself I think their response would be no. Quote Link to comment Share on other sites More sharing options...
Moontanman Posted April 26, 2008 Report Share Posted April 26, 2008 An interesting question for NASA. " Could you put a satellite at the moon earth Le Grange point and have it stay there for a million years? " Myself I think their response would be no. I don't see why not, I've read about plans to put objects in the Le Grange points of the Earth moon system. Jupiter has natural satalites in some of it's Le Grange points. Does it matter to this discussion that our Milky Way Galaxy has recently been shown to probably be a barred spiral? Quote Link to comment Share on other sites More sharing options...
modest Posted April 26, 2008 Report Share Posted April 26, 2008 An interesting question for NASA. " Could you put a satellite at the moon earth Le Grange point and have it stay there for a million years? " Myself I think their response would be no. I don't see why not, I've read about plans to put objects in the Le Grange points of the Earth moon system. Jupiter has natural satalites in some of it's Le Grange points. Does it matter to this discussion that our Milky Way Galaxy has recently been shown to probably be a barred spiral? I had a good source on this, but can't at the moment find it... Maybe I posted it in the dynamic equilibrium thread. In any case, the L4 and L5 points are stable and I think Jupiter has satellites there. L1, L2, and L3 are not stable and it takes a good amount of fuel to keep spacecraft there. Here's a source, even if it's not the best: If the heavy body is sufficiently massive compared with the light one, then L4 and L5 are stable positions, but L1, L2 and L3 are always unstable—a probe placed there will gradually wander away. However, the whole point of control engineering is to stabilise the unstable, and it turns out that regular, but relatively small, expenditures of fuel can keep a probe close to an unstable Lagrange point for decades. -source Quote Link to comment Share on other sites More sharing options...
modest Posted April 26, 2008 Report Share Posted April 26, 2008 Are there any examples or observations of something natural (not something human made) at a L1, L2, or L3 point? Has that ever been observed?Fair question. I've already answer it above. The answer, at least with respect to the L1 point, is yes. I've also provided images of a large variety systems where the L1 point is occupied. I don't really understand that. How could you find a Lagrange point in those pictures and what would they be relative to? For instance, how would a globular cluster have a Lagrange point? A particular star in the cluster with its orbit relative to the whole cluster I understand. But, just looking at the whole cluster and picking a spot for L1 - I don't get. Caranicolas writes regarding this orbit in barred galaxy models:Looks good, it will take me a while to go over it. Here the reader might respond...What proof do we have that, in the real world, barred galaxies exhibit Lagrangian (and Hamiltonian) dynamics?... Good question. The answer: complimenting your own question :esmoking: -modest Quote Link to comment Share on other sites More sharing options...
coldcreation Posted April 26, 2008 Author Report Share Posted April 26, 2008 I don't really understand that. How could you find a Lagrange point in those pictures and what would they be relative to? For instance, how would a globular cluster have a Lagrange point? A particular star in the cluster with its orbit relative to the whole cluster I understand. But, just looking at the whole cluster and picking a spot for L1 - I don't get. I had not portrayed globular clusters above for that very reason. In those systems, it is apparent, unlike many others, that there would be no global L1 point. Locally, between each star, there would inevitably not just L1 points but other L-points as well. And yet, globular clusters are some of the oldest structures in the universe. Here is a beautiful example (a QuickTime simulation) of what could possibly be the dynamics of such systems. Note, however, at the end of the vid all the stars disperse into surrounding space: this may be a little whimsical, since so far, all of the evidence is that they are stable systems for time-scales exceeding the age of the universe. :eek2: EVOLUTION OF A STAR CLUSTER There is an interesting feature, or two, about this simulation: The stars do not appear to be rotating about a central axis or point. They look as if they are orbiting, albeit chaotically or 'randomly,' around one another first (possibly for the reason I mentioned above, i.e., there is no central L1 point). In other words, there is no global rotational curve, as many galaxies would have (but I need to research this more before delving further). I'm sure some GC's rotate. What would be interesting to see is if in all such systems there is the type of intrinsic motion to all the components observed in the simulation. I would bet that some are quite static. More in line with this: Million Star Cluster NGC 2808 Profile http://youtube.com/watch?v=HD5ZZoVXB00 In this video (below), stop the image at 20 seconds, you will notice the beginning of a structure that looks Lagrangian. Though this is only a simulation. We cannot see the central core of real globular cluster, as portrayed here. But I would think that the nucleus of these systems are indeed extremely tightly bounded binary stars or quadruple stars (neutron stars perhaps) with their respective L-points filled to the max. In that way at least the nucleus would be stable for Gyr time-scales. NGC 104/47 Tucanae Globular Cluster, animation http://youtube.com/watch?v=3K2RwafhNtc Or this which looks similar even though it represents galaxies as opposed to stars: 100 Galaxy Simulation http://youtube.com/watch?v=7_pcSZAnXvw complimenting your own question :) You caught that. :hyper: PS. Isn't anyone going to give me any Rep Points for all the :esmoking: work I put into this thread? CC DougF 1 Quote Link to comment Share on other sites More sharing options...
Little Bang Posted April 26, 2008 Report Share Posted April 26, 2008 CC, I for one am astounded by the huge amount of work you have put forth and I do give you points. Moon, I am unaware of these objects you say exist in Jupiter's Le Grange points, could you name them for me please. Quote Link to comment Share on other sites More sharing options...
coldcreation Posted April 26, 2008 Author Report Share Posted April 26, 2008 Here is a nice document to find info about objects in L-points here in the solar system. Lagrange Points, John Baez, December 19, 2005 Trojan asteroids So far a total of 1691 asteroids called "Trojans" have been found orbiting the stable Lagrange points of Jupiter's orbit around the sun. 1691, wow. CC Quote Link to comment Share on other sites More sharing options...
Moontanman Posted April 26, 2008 Report Share Posted April 26, 2008 Here is a nice document to find info about objects in L-points here in the solar system. Lagrange Points, John, Baez, December 19, 2005 1691, wow. CC You beat me to it CC but WOW is the right word:) Quote Link to comment Share on other sites More sharing options...
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