murshid Posted February 27, 2012 Share Posted February 27, 2012 (edited) . What do you guys think of this news: "Is the Universe Spinning?" On the face of it, the claim of a spin axis would seem anti-Copernican. In other words, the universe has a preferred axis, which means there is indeed a special direction in space. What is very curious to me is that the Milky Way's own spin axis roughly aligns to the universe's purported spin axis within just a few degrees, as deduced from the two galaxy surveys. That seems very anti-Copernican too. It has also been used to bolster biblical creationist arguments that we are at the "center" of the universe. What is the universe spinning with respect to? Has there been any further developments regarding the discovery? . Edited February 27, 2012 by murshid Link to comment Share on other sites More sharing options...
swansont Posted February 27, 2012 Share Posted February 27, 2012 This result might just be a statistical fluke. Or is it somehow biased because we are only looking at the local universe? One has to remember that sampling error assumes a random sample. Local sampling is not random. Link to comment Share on other sites More sharing options...
JohnStu Posted February 29, 2012 Share Posted February 29, 2012 What do you mean by THE universe. They have yet to map out the other half of the Universe. The stars in milky way has been blocking the view. Galaxies spin, yes. Overall galaxy groups are not spnining as galaxies are too distant apart from each other that their gravitational effect is less than me on the galaxy. Link to comment Share on other sites More sharing options...
murshid Posted February 29, 2012 Author Share Posted February 29, 2012 What do you mean by THE universe. They have yet to map out the other half of the Universe. The stars in milky way has been blocking the view. Galaxies spin, yes. Overall galaxy groups are not spnining as galaxies are too distant apart from each other that their gravitational effect is less than me on the galaxy. I was also not sure what the article (http://news.discovery.com/space/do-we-live-in-a-spinning-universe-110708.html) meant by "the universe". Perhaps they meant the observable universe, although I can't be sure. . Link to comment Share on other sites More sharing options...
DrRocket Posted February 29, 2012 Share Posted February 29, 2012 One has to remember that sampling error assumes a random sample. Local sampling is not random. Right. One might suspect that superluminal neutrinos are at the heart of this phenomena. Link to comment Share on other sites More sharing options...
Schrödinger's hat Posted February 29, 2012 Share Posted February 29, 2012 What do you mean by THE universe. They have yet to map out the other half of the Universe. The stars in milky way has been blocking the view. Galaxies spin, yes. Overall galaxy groups are not spnining as galaxies are too distant apart from each other that their gravitational effect is less than me on the galaxy. What do YOU mean by the universe? There's only a limited region we will ever see, barring completely overturning the known laws of physics. Also clusters of galaxies still have a net angular momentum and gravitational interaction. So you can say that they are spinning, even if they will never do anything resembling a full orbit. Link to comment Share on other sites More sharing options...
elfmotat Posted February 29, 2012 Share Posted February 29, 2012 I couldn't really tell what the article meant by "spinning universe." If it's implying that the universe is anything like Godel's rotating universe model, then we definitely have significant reason to doubt it. Link to comment Share on other sites More sharing options...
guenter Posted February 29, 2012 Share Posted February 29, 2012 One might suspect that superluminal neutrinos are at the heart of this phenomena. Could you explain this idea? Thanks. Link to comment Share on other sites More sharing options...
DrRocket Posted February 29, 2012 Share Posted February 29, 2012 Could you explain this idea? Thanks. Notice the smiley. I couldn't really tell what the article meant by "spinning universe." If it's implying that the universe is anything like Godel's rotating universe model, then we definitely have significant reason to doubt it. The article speaks of a somewhat statistically preferred direction for the net angular momentum of rotating galaxies. I don't think it has anything to do with Godel's rotating universe model. The title of the article seems to have been selected to titillate. Link to comment Share on other sites More sharing options...
Airbrush Posted February 29, 2012 Share Posted February 29, 2012 (edited) What do you mean by THE universe. They have yet to map out the other half of the Universe. The stars in milky way has been blocking the view. Galaxies spin, yes. Overall galaxy groups are not spnining as galaxies are too distant apart from each other that their gravitational effect is less than me on the galaxy. The clouds of dust in our galaxy conceal a narrow band of the universe from us, not "half of the universe". What makes you think galaxies are not orbiting the center of mass of the cluster in which they are located? Everything gravitationally bound is orbiting a center of mass. The only exception to this rule is on the scale of superclusters. Superclusters do not seem to be orbiting other superclusters, but rather flying apart at an accelerating rate. Edited February 29, 2012 by Airbrush 1 Link to comment Share on other sites More sharing options...
JohnStu Posted February 29, 2012 Share Posted February 29, 2012 The clouds of dust in our galaxy conceal a narrow band of the universe from us, not "half of the universe". What makes you think galaxies are not orbiting the center of mass of the cluster in which they are located? Everything gravitationally bound is orbiting a center of mass. The only exception to this rule is on the scale of superclusters. Superclusters do not seem to be orbiting other superclusters, but rather flying apart at an accelerating rate. I solidly believe that a nearby star has much more gravitational influence on the galaxy than superclusters "nearby". Link to comment Share on other sites More sharing options...
swansont Posted February 29, 2012 Share Posted February 29, 2012 I solidly believe that a nearby star has much more gravitational influence on the galaxy than superclusters "nearby". The great thing about science is that you don't have to settle for belief. If you have enough information, you could actually calculate this. All you need is the mass and the distance. Link to comment Share on other sites More sharing options...
DrRocket Posted February 29, 2012 Share Posted February 29, 2012 What makes you think galaxies are not orbiting the center of mass of the cluster in which they are located? What makes you think that that they are ? Have you solved the general n-body problem that has eluded scientists and mathematicians for the past couple of centuries ? http://en.wikipedia.org/wiki/N-body_problem -1 Link to comment Share on other sites More sharing options...
Airbrush Posted February 29, 2012 Share Posted February 29, 2012 What makes you think that that they are ? Have you solved the general n-body problem that has eluded scientists and mathematicians for the past couple of centuries ? http://en.wikipedia.org/wiki/N-body_problem So you suggest that because we cannot accurately predict the motion of several dozen galaxies in a cluster, they are not orbiting their ever-changing center of gravity? Does anybody here agree with Dr Rocket on this? It seems obvious that a cluster of galaxies remain bound by gravity. So they have to move relative to the cluster, and what other motion is possible, except for irregular orbits around their common center of mass. 1 Link to comment Share on other sites More sharing options...
JohnStu Posted February 29, 2012 Share Posted February 29, 2012 So you suggest that because we cannot accurately predict the motion of several dozen galaxies in a cluster, they are not orbiting their ever-changing center of gravity? Does anybody here agree with Dr Rocket on this? It seems obvious that a cluster of galaxies remain bound by gravity. So they have to move relative to the cluster, and what other motion is possible, except for irregular orbits around their common center of mass. Galaxies are too far apart to have any influence on one another. They more so float on their own than spin around something in a group. -2 Link to comment Share on other sites More sharing options...
Airbrush Posted February 29, 2012 Share Posted February 29, 2012 (edited) Galaxies are too far apart to have any influence on one another. They more so float on their own than spin around something in a group. Galaxies are not too far apart to influence each other. You should take a look at what wiki says about "galaxy clusters". "....When observed visually, clusters appear to be collections of galaxies held together by mutual gravitational attraction. However, their velocities are too large for them to remain gravitationally bound by their mutual attractions, implying the presence of either an additional invisible mass component, or an additional attractive force besides gravity. X-ray studies have revealed the presence of large amounts of intergalactic gas known as the intracluster medium. This gas is very hot, between 107K and 108K, and hence emits X-rays in the form of bremsstrahlung and atomic line emission. The total mass of the gas is greater than that of the galaxies by roughly a factor of two. However this is still not enough mass to keep the galaxies in the cluster. Since this gas is in approximate hydrostatic equilibrium with the overall cluster gravitational field, the total mass distribution can be determined. It turns out the total mass deduced from this measurement is approximately six times larger than the mass of the galaxies or the hot gas. The missing component is known as dark matter and its nature is unknown." http://en.wikipedia.org/wiki/Galaxy_clusters Edited February 29, 2012 by Airbrush 1 Link to comment Share on other sites More sharing options...
DrRocket Posted March 1, 2012 Share Posted March 1, 2012 (edited) So you suggest that because we cannot accurately predict the motion of several dozen galaxies in a cluster, they are not orbiting their ever-changing center of gravity? Does anybody here agree with Dr Rocket on this? It seems obvious that a cluster of galaxies remain bound by gravity. So they have to move relative to the cluster, and what other motion is possible, except for irregular orbits around their common center of mass. Go read the link. The center of mass of any closed gravitational system does not move relative to the inertial reference frame in which the initial total momentum of the system is zero, and is in uniform motion in any other inertial reference frame. That fact follows from a simple application of Newton's third law, so it is not "ever-changing". (See Classical Mechanics by Goldstein, page 5) Gravitational motion need not be anything that anyone in their right mind would call an "orbit" except in the most abstract mathematical sense. In fact (again read the link) there are systems that are characterized as chaotic. It doesn't matter whether anyone here agrees or not. Physics wins. The point is that gravitational systems have been studied for quite a long time and it is well-known that systems with 3 or more bodies can have motions that are not describable in closed form and that those motions need not look anything like "orbits around the common center of mass." If you prefer books, here are some useful references: Classical Mechanics -- Goldstein Classical Dynamics of Particles and Systems -- Marion (see page 279 of 2nd edition for a nice overview of the 3-body problem) A Treatise on the Analytical Dynamics of Particles and Rigid Bodies -- Whittaker An Introduction to the Mathematics and Methods of Astrodynamics -- Battin New Methods of Celestial Mechanics -- Poincare Edited March 1, 2012 by DrRocket Link to comment Share on other sites More sharing options...
Airbrush Posted March 3, 2012 Share Posted March 3, 2012 .....Gravitational motion need not be anything that anyone in their right mind would call an "orbit" except in the most abstract mathematical sense. In fact (again read the link) there are systems that are characterized as chaotic. It doesn't matter whether anyone here agrees or not. Physics wins. The point is that gravitational systems have been studied for quite a long time and it is well-known that systems with 3 or more bodies can have motions that are not describable in closed form and that those motions need not look anything like "orbits around the common center of mass." Well then, that is how I mean it "in the most abstract sense". I appreciate your knowledge on this, which exceeds mine, but you cannot say galaxies in a cluster are not moving relative to each other. They move and yet they are bound by gravity. They are bound forever by gravity, unless they can throw a galaxy out. They "orbit" or jostle past each other, or tear each other apart, and collide, but they are always moving through a changing center of mass, otherwise they would fly apart. 1 Link to comment Share on other sites More sharing options...
MigL Posted March 3, 2012 Share Posted March 3, 2012 I'm sure DrR is just trying to get you going by being very picky with the definition of solution. I'm sure he's more familiar than most with perturbation and approximate methods. There may be no exact solution to many body problems, but given enough computer time, you can get as close ( decimal places ) as you wish. I, myself have not done any >2 body gravitational approximations. But I'm sure anyone who'se studied physics will have solved the Helium atom using these methods. At the time I was in school we used Hollerith punch cards and programmed in Fortran IV. Several hours later you'd have your stack of fanfold results which then needed debugging. Ah, the convenience of modern computers. Link to comment Share on other sites More sharing options...
Alberto Posted May 26, 2012 Share Posted May 26, 2012 What is the universe spinning with respect to? The observations show that the spiral galaxies' axis are strangely alined for the galaxies belonging to a wall. It doesn't seem that the Universe possesses a spin axis of its own, though the existence of such a feature as the Axis of Evil is really curious. At the same time, the rotational or better say tangential motions in the Universe are definitely underestimated (see, for example, the Anisotropic Geometrodynamics theory). Link to comment Share on other sites More sharing options...
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