"Low surface brightness" galaxies like F549-1 lend greater precision to the Mond theory's predictions.



We've long known that our Milky Way galaxy will collide with its neighbor Andromeda in about four billion years. But some European astronomers think this is a case of deja vu - that we have collided once before, long ago. This would explain puzzling structures in both our galaxies, and the odd existence of our tiny satellite galaxies like the Magellanic clouds.

But it would mean that dark matter does not exist. And our ideas about how gravity behaves on large scales, is wrong. It would change everything.

In 1930, the brilliant astronomer Fritz Zwicky noticed that the way groups of galaxies stay together despite their large individual speeds shows that they contain about six times more gravity than can be explained by all their stars, planets, black holes, and everything else.

The way our galaxy spins supports this, too. Some unseen entity that has gravity must dominate the scene everywhere, and we call this dark matter. This is what must be gravitationally pulling us toward Andromeda at 70 mps so that the two of us can overcome the universe's expansion.

But the need for dark matter assumes that gravity at great distances acts the same way as it does locally, which is what Newton believed, and Einstein supported in his modification of Newton's model. Yet a few maverick astronomers have long wondered if it's truly so.

Enter the modified gravity theory, called MOND, which says that gravity behaves differently on the largest scales. Instead of its power falling off rapidly with the inverse square of distance, the way it does in local neighborhoods, it weakens more and more gradually. If this is so, then we and our neighbor galaxy skimmed past each other in the distant past, but did not merge since the new gravity ideas would not have forced that to happen. It would have created the actual structures we presently see around us. It would solve a bunch of puzzles.

Moreover, if this is so, there is no need for dark matter to supply missing gravity, because no gravity is missing anywhere.

The Milky Way and Andromeda are still going to crash into each other in a few billion years. (Don't worry about it: our individual stars and planets won't collide because the spaces between everything is so enormous). But if supported by further studies, the new gravity model totally changes the age and dynamics of the whole universe. Our understanding of cosmic structure would have to be rewritten from scratch.

Why would I worry about what is going to happen a few billion years from now? I plan to live a long time but in a few billion years.... I don't think I'll be here in this galaxy.

Gravity is caused by the mass-energy density of space. This mass-energy density of space is determined by the square of the Wave-Amplitude and is always positive (squares are always positive). The Wave-Velocity is inversely proportional to the mass-energy density of space, the higher the mass-energy density of space, the slower the Wave-Velocity.

As Matter and its resultant mass-energy density of space are always positive, this causes a slowing of In-Waves as they travel through other matter/wave-motions, and it is this property of Space that causes the natural ‘Gravitational’ attraction of all bodies, and explains why Gravity is always attractive.

Thus we realise that the presence of another ‘particle’ (as the Wave-Center of a Spherical Standing Wave/electron) will add to the density of space and slow down and thus distort the in-waves. Part of the in-wave near the other particle will travel slower.

Thus the slower part will cause the center of the in-wave to continually move. We will observe this as motion of the ‘particle’ though it is actually caused by a succession of wave-centers forming in different locations in Space. Slowing occurs because the presence of the waves of the other particle increases the mass-energy density of space.

This increase is very slight compared the whole density of Space which is determined by the sum of the waves of all the matter in our Hubble Universe This Mass-energy density of space rule is Principle Two, an extended version of Mach's Principle. The small effect of one particle is the reason why gravity is such a small force - that is, about 10^-40 times smaller than the electric force.

Now You Understand the Origin of Gravity. That is it! Gravity is a result of the slowing of the In-Waves causing the wave center to move towards other Wave-Centers. Gravity has been touted as the most puzzling of the forces. Indeed, before the Wave Structure of Matter was discovered there were no explanations of gravity, only speculations.

Millions of research dollars have been, and still are being spent trying to find 'gravitons', a mythical particle similar to the 'photon' which supposedly carried energy like a pack horse between two particles. In fact we now realise that this fundamental concept of motion is the cause of all the forces in nature. This is logical thinking because the motion concept contains the meaning of force.

REF:http://www.spaceandmotion.com/Physics-Reality-Forces-Light-Gravity.htm

yea, it will be a super-galaxy then...


in a few billion years, we might live millions of lives...

Dark matter not needed:

(One of 30 problems with the Big Bang Theory)

A wrong assumption:

Invisible dark matter of an unknown but non-baryonic nature must be the dominant ingredient of the entire universe.

The Big Bang requires sprinkling galaxies, clusters, superclusters, and the universe with ever-increasing amounts of this invisible, not-yet-detected “dark matter” to keep the theory viable. Overall, over 90% of the universe must be made of something we have never detected. By contrast, Milgrom’s model (the alternative to “dark matter”) provides a one-parameter explanation that works at all scales and requires no “dark matter” to exist at any scale. (I exclude the additional 50%-100% of invisible ordinary matter inferred to exist by, e.g., MACHO studies.) Some physicists don’t like modifying the law of gravity in this way, but a finite range for natural forces is a logical necessity (not just theory) spoken of since the 17th century. [29],[30]

Milgrom’s model requires nothing more than that. Milgrom’s is an operational model rather than one based on fundamentals. But it is consistent with more complete models invoking a finite range for gravity. So Milgrom’s model provides a basis to eliminate the need for “dark matter” in the universe at any scale. This represents one more Big Bang “fudge factor” no longer needed

REF: http://www.spaceandmotion.com/cosmology/top-30-problems-big-bang-theory.htm

How do you explain the mass or air above you acting on you whole body?
If you get to where there is no air over you but air is below you, hoe do you explain the situation?
Gravity, magnectic pull, anyway it must be described anyway.
AIR OVER YOU OR BELOW YOU MUST BE UNDERSTOOD AS "PRESSURE OF AIR ACTING DONWARDS OR UPWARDS"
Pressure of air acting downwards is calculated as 10 or 9.8 killometers of the pressure air over a centimeter of your superficial body (any part of your skin).
It's simple logic.

air pressure is the weight of the air that is trapped by gravity, the same way water gets more pressure the deeper you go... not sure what this has to do with the subject...

Gravity sucks.

What I have always wondered is why gravity seems to be the only force mentioned when people talk about forces over large distances. I understand that it is really simple to calculate that it is a attractive force and very large when you add up the entire weight of a star for example. But nobody talks about the forces of anything else. Like our planet for instance we know that it is a big magnet right. Lets say there is another earth like planet somewhere in the galaxy what kind of forces are we talking about there? Small? but what if you take all those add them up does that span across to another galaxy? I don't know I don't know enough about the elector-magenetic forces.

M. moe,
Mond is interesting, and it attempts to go in the right direction by proposing a new law that may make predictions, but from the wikipedia article I read it seems to be limited to astronomical data and not really be a theory, so to say. The main problem is that bodies in the galaxy, when the rotate further out from the center of a galaxy, do so at about the same speed as bodies close in. SO that goes against the experience of Newton's gravity as observed by planets in the solar sytem slowing down as they are further away from the sun. Perhaps this could be because the galactic disc, the plate where all the stars are, is rotating as a whole, something akin to frame dragging. But I would be really surprised if astronomers, who are quite capable of using relativty theory, did not check for this. Another idea is that mass-gravity interaction is different (what MOND type ideas propose), or that there is missing matter, so that we just have the quantity game mixed up. What is more interesting to me is that the quality of mass changes with time. I see where you are coming from about our galaxy not having collided with another being supported by this modification, but I can't say that this is the exact right formulation of that likely trend. The constant, which may be called R, that he produces is also of interest. I sometimes think that it sets a resonable explanation on the upper limit of light speed. What is most exciting about MOND is that at some levels it specks of the possibility of non-classical acceleration.
Torgo, Gravity doesn't suck, just imagine being in free fall and you'll see that it is completely weightless. It is the force of the earth pushing up on us and resisting gravity that is the common burden.
Penny, It is odd that physicists don't talk about elctromagnetism at long ranges, besides light being a common discussion point. One would think that it would be stronger and than the weak gravitation at distances.
Jean, that article you refferenced first was interesting. I'm sure that Ein would have liked that it is simple to read and shows the philosophical ideas bare. I'm not sure that the wave-mechanical model is valid anymore for a foundation of physics, however much of a part the successes of relativity that use it will have to be included in any new ideas or fundations taht scientists cook up. I think Original's pressure thinking could be seen as a very local Mach's principle, which is always something neat to think about.

What I think about gravity is that as our understanding of physcis from a theoretical view is cleaned up, when we can talk about qm and relativity and why laws are what they are, then the gravity at expanded or far away scales will fall into place. Why is generally not talked about traditionally in the sciences, but it must if a new, deeper understanding is to come about. The results of astronomy are remarkable, and they can help guide our philosophy, but a new view of matter and physics in general, if it's right, will have to include everything, small and large and close and far away. I don't think that it is too far of a stretch to say that the age of the universe will someday be equivalent to the statement of "when the laws currently observed took their recognized form."

it's all a theory, just as Quantum Mechanics takes the "dark energy/matter" out of the picture... from our little corner of the universe, and seeing we only have 1 man made object that has even left our solar system, we have only educated guesses on whats really happening out there...