# Theoretical Possibility of "Opposite" Gravitational Mass?

Discussion in 'Physics & Math' started by eram, Feb 24, 2016.

1. ### eramSciengineerValued Senior Member

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This is an unusual idea that I have been entertaining for some time, and I can't find anything about it online.
However, it is so simple that someone must have conceived it before.

First, I will elaborate my idea, then I will ask if it possible within the framework of General Relativity.

There are two types of electric charge, positive and negative. Like charges repel, unlike charges attract.

Could there be two types of gravitational mass? Let's call them Д - mass and Ξ - mass.
They could a follow a similar but opposite rule to electric charges: like masses attract, and unlike masses repel.

We assume that both Д and Ξ masses have the same inertial masses.

Д - mass is the type of mass that we're all made out of, our bodies, our planets, our solar system. Ξ - mass would be the"opposite" type of mass.

Like masses attract, so we see that every bit of Д - mass gravitationally attracts every other bit of Д - mass. Using Newton's laws, we can obtain Galileo's Law of Falling Bodies, which is the basis of Einstein's equivalence principle.

Inertial masses remain the same. Falling objects on a planet made out of Ξ - mass would be kinematically indistinguishable from one made out of Д - mass.

Let's say one day a meteorite crashes onto Earth. It is a relatively ordinary meteorite, except that embedded within it are chunks of very pure Ξ - mass. When such a chunk is pried out, it falls up! It would fall towards the sky and keep going.

If we measure the acceleration of the up-falling chunks, we would see that it is also 9.81 ms-2.

If we combine two equal Д and Ξ masses, we can produce a gravitationally "neutral" mass, one that can float weightlessly. However, it will still have inertial mass.

We have not observed any neutral or Ξ masses. This is similar to the issue of baryon asymmetry. Due to like masses attracting and unlike masses repelling, this could result in increasing separation between the two types, and any Ξ masses in our universe might be really, really, really far away.

My final question is whether the existence of this "opposite" Ξ - mass is possible within the framework of General Relativity. Does the resulting repulsion and "falling up" violate the equivalence principle?

3. ### mathmanValued Senior Member

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I don't know if - mass is possible, but there is no evidence such things exist.

5. ### eramSciengineerValued Senior Member

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I just need to know if they are allowed by General Relativity

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7. ### danshawenValued Senior Member

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No repulsive gravitational force is known or predicted by theories like General Relativity.

It IS known that bulk antimatter and even masses as small as that of neutrinos are uniformly attracted by gravitation to other bulk matter and/or antimatter, and in all cases, the Principle of Equivalence (equivalence of inertial, gravitational masses) seems to be valid to a high degree of experimental accuracy. If the force of gravity was repulsive rather than attractive, it would probably not change the situation very much in terms of the Principle of Equivalence for the reason discussed in the next paragraph.

You might have noticed that standing upright in the North American continent means that gravitational force is pulling you in a diametrically opposite direction from the gravitational force exerted on a person standing in Australia. If the persons are of equal weight, all else being equal, the force pair vector sums to zero (NO net gravity). This is something of a hint as to why a repulsive gravitational force analogous to that experienced by like electrically charged particles is probably not possible.

But even if there were some exotic particle which experienced a gravitational repulsion, If it were possible to get enough of it to remain aggregated in a single location, it wouldn't stay that way for long, for the same reason that there isn't a net buildup of the same polarity of electric charge aggregated in one location. The tendency is either to fly apart, or attract particles of opposite polarity so that the charges cancel each other out, leaving the combination electrically neutral.

8. ### eramSciengineerValued Senior Member

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So does my idea of Ξ - mass directly contradict General Relativity?

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9. ### Edont KnoffRegistered Senior Member

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I heard about negative mass, which has negative gravity as result in some scenarios. So it's thought about, and as far as I know, Einsteins formulas do not forbid negative mass.

But we never observed a thing like that.

So, theory yes, practical, no.

10. ### danshawenValued Senior Member

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No, it doesn't contradict General Relativity.

Vera Rubin, a Cornell astrophysicist (and also a friend of a friend, actually) who made the discovery of the anomalous "dark matter" requirement for spiral galaxies would probably tell you, your Ξ - masses might fill the bill. Vera discovered that the respective velocities of the outer 1/3 of most galaxies were ALREADY moving fast enough to escape the gravitational pull exerted on them from the inside disk. Since this was not happening, it was pretty apparent that more mass than what we could see was involved.

It is believed that the "dark matter" was NOT AS STRONGLY ATTRACTED to the centers of masses of gravitating bodies made of "baryonic" matter. It sort of "hangs out" in the vicinity of gravitating objects, but does not "fall" under the influence of gravity in the conventional sense we currently understand gravity.

Now of course, there are detractors of Vera's theory. She's no stranger to controversy, to say the least. Some dark matter detractors suggest MOND (Modified Newtonian Dynamics) to replace General Relativity, to explain the anomalous escape velocities. But we already know, General Relativity is a much better theory for predicting the effects of gravity than anything Newton (or even MOND) ever came up with.

Vera herself was discriminated against, being turned down for graduate work in astrophysics by Princeton, just because she was a woman. Her discovery of dark matter is still not adequately explained by all of the notable astrophysics in that previously male dominated field. How could they possibly have missed making such an important discovery themselves? Obviously, they had a testosterone deficiency.

Majorana Fermions (a bosonic counterpart to electrons) are one idea astrophysicists and particle physicists have been toying with to explain the effect of Vera's "dark matter".

Here's another. I speculate that the Higgs field (a quantum field) and the excitation of that field, the Higgs boson, are the go-between force between rotational and linear propagation modes for all forms of energy in a universe that consists entirely of energy transfer events. The Higgs imparts inertial mass to electrons, electroweak bosons and their antiparticles, and those particles IMPART INERTIAL MASS back to Higgs. So far, this is just known Standard Model stuff. But the Higgs is the ONLY quantum spin zero particle, and the fundamental particle of the SM. Without Higgs, the whole model (the Standard Model of particle physics) literally comes apart. It's real alright. Five or Six Sigma is as real as something gets. And the confidence in the principle of equivalence is even higher, and E=mc^2 higher still, yet a great majority of particle physicists still insist, the majority of the mass of an atom is 98% color charge interactions between quarks and gluons. They ignore the simple fact that mass and energy are equivalent forms of the same thing, and that the way unbound energy becomes bound to make matter is through a transition to a rotational form of propagation from a linear one. This is old science. 1940s. In the 21st century, it isn't real science unless it involves at least SU(10) or something. Hilbert was a 19th century mathematician, and not even a particularly good one, yet somehow in the 21st century his math, an the math of his mentor Minkowski is more influential in physics than Einstein's relativity ever was. Both Hilbert and Minkowski were enamored of quadratics. If the universe wasn't quadratic, well, where would Pythagorus and higher Euclidean spaces fit in? Go figure, and then figure again.

Inertia is something that seems to be little understood. It is BOTH about matter at rest AND ALSO about energy in motion. Both states are literally defined by the speed of light. Both states are Lorentz invariants. But a piece was always missing from that simple model. It is the quantum spin zero particle that is Higgs. The only way something can be spin zero is for it to contain propagating energy that is of equal and opposite quantum spins, in exactly the same way that matter "at rest" is determined by ±c in opposite directions. This is why Higgs is the only thing that interacts with matter. That spin is why planets (and electrons and atoms) are round. Can Ξ - mass explain that?

After the Higgs interacts with baryonic matter to impart inertial mass, it gets inertial mass itself in the form of quantum spin that is briefly not zero. It couples this spin into the vacuum surrounding gravitating objects, and sort of "hangs out" there until the inverse square law causes the excess spin to spread out the same way that photons do from accelerated electrons.

This explains everything you'd want to know about gravitation and also dark matter without resorting to Ξ - mass, does it not?

Look at my icon. There's a good reason, it's a a picture of a crank from a graphic of an antique pencil sharpener. I know the other cranks, too, but some of them believe they are scientists. And mathematicians believe they are scientists also. But they make better cranks because it takes a little more effort to understand their deliberately obtuse shorthand / language.

Last edited: Feb 25, 2016
11. ### brucepValued Senior Member

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In GR stuff falls over the natural geodesic path. It's a path of extremal aging. Extremal is either a maximum or minimum. For stuff with mass, fermions, it's a maximum and for stuff without mass, bosons, it's a minimum. The null geodesic. In GR the pressure component, the anti gravity component, is the cosmological constant. There's no indication that something with negative mass would 'fall up' instead of 'fall down' . Falling 'up' instead of 'down' is just a choice of coordinates. The rate stuff falls has nothing to do with mass. How would this negative mass differ from mass? Why would it be repulsed and by what? The negative energy density between the Casimir uncharged plates doesn't repulse the plates. If mass and negative mass fell in opposite directions they'd still fall at the same rate. Know where to find some?

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12. ### Waiter_2001Registered Senior Member

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I see your argument poster. Would something fall upwards? Well astronauts practice zero gravity by passengering a plane flying towards the planet at, or faster than gravity. The result is negation. Gravity ceases to exist. Operating on this theory something thrown at the ground should take longer to reach said floor than something dropped. So yes, I imagine it is possible for something to fall towards the sky.

13. ### brucepValued Senior Member

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Hi Waiter_2001
Just to clarify something for you. When you drop something, a bowling ball, from some height over the Earths surface the path it follows is the freefall path you mentioned. It's a local freefall [inertial] geodesic obeying Newton' First Law. Over this path the objects momentum, angular momentum, and total energy are constants of the motion [conserved]. No forces acting upon the object as it follows the natural path. So why do we stick to the Earths surface, why does the bowling ball stop following the natural path? What would happen if the Earth suddenly disappeared? The first two queries have the same answer. The Earth blocks our natural path by a force equivalent to g_earth surface. We can't continue our natural inertial path because the earth is in the way. Good huh. LOL. The third query has this answer. If the earth suddenly quit blocking the natural path we would begin falling again. Free float, orbits, ... are natural paths also. GR models gravity as local phenomena. Gravity is the local spacetime curvature. It doesn't push or pull it just determines the path of the falling objects. The theory is mostly about analyzing these geodesic paths. This is the amazing thing. These local paths are essentially straight over very large areas in the weak field such as our solar system. The entire universe for the most part. This is because the local spacetime curvature is an infinitesimal. Even in the strong field it's still an infinitesimal. Just a shrinking tangent space as the local spacetime curvature increases. Flat wherever the falling object is located. Straight just like the path of the falling bowling ball. Straight like the path your flashlight makes when you shine it down to see where the bowling ball hit. LOL Geodesic paths associated with frame dependent coordinates are global because the local spacetime curvature is summed over the entire geodesic path when calculated from remote frame dependent position coordinates.

So let's just consider the idea of negative mass. Why would it's natural path, geodesic, be different from any other object with mass? It's path through the local spacetime curvature, which is gravity, as modeled by GR.

Last edited: Feb 28, 2016

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15. ### danshawenValued Senior Member

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About three paragraphs into the article, the Higgs-dark matter connection I mentioned is actually discussed.

Some folks around here even got bent out of shape when I referenced a few Higgs-inflation theory links that did not jibe with their understandings of mainstream cosmology. I might make some of this stuff up, just not as much of it as some people here seem to believe.

Welcome to the forum, by the way.

16. ### The GodValued Senior Member

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I give you a clue, a very basic clue ...object's momentum does not remain conserved when you drop something frome some height..........once you get it, please correct the statement(s)..

Last edited: Feb 29, 2016
17. ### Q-reeusBannedValued Senior Member

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You have to be kidding. Well evidently not. I just type in 'negative mass' and a Google search instantly comes up with a huge list of hits dealing precisely with that notion.
Also, the topic has at least indirectly come up at SF *numerous* times (e.g. in relation to Hawking radiation) and it's hard to believe you never noticed.

And btw are you ever going to go back and face the music here: http://www.sciforums.com/threads/something-wrong-with-amperes-law.152751/
Noticed that under your alter ego greswd at another forum site, you similarly just went to ground after posing the identical claim there.

Last edited: Feb 29, 2016
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18. ### danshawenValued Senior Member

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"When you drop something from some height", that "something" made of bound energy CONTINUOUSLY interacts with something in the vacuum to SUPPORT AND MAINTAIN its atomic structure while it falls, doesn't it? What is it that you think imparts the force IDENTICALLY EQUAL TO ITS INERTIA that generates the impulse needed to make something fall when you drop it? What rotational dynamic makes something fall in a different direction based on its position relative to the surface of the gravitating body? What force is it that makes the gravitating body as round as its atomic and subatomic structure is? Can't quite work out the hierarchy problem. The answer is dangling in front of your noses, if you would only direct your gazes away from your intricate geometry calculations once in a while.

That's right. The fundamental particle of the Standard Model of particle pseudoscience makes all of this dynamic possible. Either that, or the infinite fascination and fixation of mathematics upon static geometry in Euclidean relativistic space and the holy quadratic-conical oracles, Lie groups and higher dimension Hilbert spaces would be my guess.

But I'm not mocking any of those. That would be foolhardy, and the end of any formerly promising academic career so heavily invested in them.

Last edited: Feb 29, 2016
19. ### originHeading towards oblivionValued Senior Member

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It is always so sad to see your uneducated opinion presented in such a nasty way to people that actually have a good understanding of the physics involved.

20. ### brucepValued Senior Member

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No. You're either making it up or confused about what you're reading. Plus your disagreement with science and well known scientists is juvenile nonsense. The only reason I looked at your post is to find out which crank origin was referring to. Idiot wind bullshit is what's consistent in your nonsense rethoric.

21. ### The GodValued Senior Member

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• Please do not insult other members.
Its pathetic 'origin', that you fall on your knees in front of this admitted illiterate and uncivilized Brucep...You are an engineer so you know very well that the momentum of the object when dropped from a height is not conserved, it is the system momentum (Object + Earth) that is conserved....go back to this guy's post and see what he said, then you will realise your folly.......you have to try really hard to find mistakes in my posts.

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Let me count the ways.....
In recent times though your total arrogant and unsupported nonsense re the GP-B results and LIGO are at the top of the list.
Both stand as astonishing precision experiments, both confirm spacetime curvature and both further give credibility to GR, not that it really needed it.

23. ### The GodValued Senior Member

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They are not mistakes..You can't even figure out what qualify as mistakes ? Its better for you to swim with the flow...