Talk:Negative mass

Would it be appropriate to have an historical section on the theory of negative-mass phlogiston?

Jbom1 (talk) 16:16, 9 February 2011 (UTC)

Cancelation of a positive mass and a negative mass

The following was stated: Forward also coined a term, "nullification" to describe what happens when ordinary matter and negative matter meet: they are expected to be able to "cancel-out" or "nullify" each other's existence. An interaction between equal quantities of positive mass matter (hence of positive energy E = m c^2) and negative mass matter (of negative energy -E = -m c^2) would release no energy,

Taking that at face value, doesn't that violate the principle of the Conservation of energy? It's destroying matter and even though the net energy of the system is zero, it just doesn't sit right with me. It sounds like a magical way to get rid of stuff that you don't want and not have it create any side reactions. Thoughts? Kedamono (talk) 04:46, 19 January 2015 (UTC)

Clarification

In the last sentence: "This behavior implies that both have positive inertial mass and opposite charges; if the reverse were true, then the particle with positive inertial mass would be repelled from its antiparticle partner." ... does "the reverse" in the phrase "if the reverse were true" mean that (1.) both particles have both opposite inertial mass and opposite charges, or that (2.) both particles have opposite inertial mass and both have the same charge? --Cowlinator (talk) 00:24, 6 March 2011 (UTC)

Indeed - consider 2 scenarios:

(i) Particle and antiparticle have opposite charges but both have positive mass. They are obviously attracted to each other and (by Newton's second law) move towards each other.

(ii) Particle and antiparticle both have positive (or negative) charge and opposite mass. The positive mass particle is repelled from the negative mass particle and (again by Newton's second law) moves away from it. However, the negative mass particle is repelled from the positive mass particle, but begause of its negative mass it moves in the opposite direction to this repulsion. The particle therefore "flees away" from the antiparticle, but the antiparticle "chases after" it.

Is the latter scenario ever observed?

Another problem with negative mass antiparticles is that their masses would cancel with those of their corresponding positive-mass particles on recombination, and no net enwrgy would be released on anihilation. The explosion in Dan Brown's "Angels and Demons" would have been less of a bang than a whimper!— Preceding unsigned comment added by 141.241.199.124 (talk) 09:33, 3 June 2011 (UTC)

When you say 'The particle therefore "flees away" from the antiparticle, but the antiparticle "chases after" it.', I thought you were saying it "flees away" due to gravity, but "chases after" due to electromagnetism. However, obviously, electromagnetism is so much stronger than gravity in situations where antiparticles are created that the effects of gravity should be ignored. Gravity has no measurable effect. There is a symmetry (see my post "From the article, it's not clear why opposite mass but same charge would repel" below) that suggests opposite mass with like-charge should neither repel nor attract by electrostatic force.

I realize after writing my post below that it's the same thing you are saying. The particles would stay the same distance from each other, but would accelerate towards the positive mass. This is also what happens with gravity in this situation according to the article: "Bondi pointed out that two objects of equal and opposite mass would produce a constant acceleration of the system towards the positive mass object." So, even including gravity, this last sentence of the article is just wrong or contradictory with the rest of the article.

 — Preceding unsigned comment added by Colinkeenan (talk • contribs) 05:34, 26 October 2013 (UTC) 

Contradiction

Something is very wrong here. At the end of Negative mass#Inertial versus gravitational the following is said:

So, as long as inertial mass and gravitational mass are always equal as required by the equivalence principle, positive active gravitational mass would be universally attractive (both negative-mass and positive-mass objects would be pulled towards an object with positive active gravitational mass), while negative active gravitational mass would be universally repulsive (both negative-mass and positive-mass objects would be pushed away).

It first says that "positive active gravitational mass would be universally attractive", that is "both negative-mass and positive-mass objects would be pulled towards" them. However, the next sentence says that objects with "negative active gravitational mass would be universally repulsive". Assuming indeed that active and passive gravitational masses are the same, this leads to a clear contradiction: A negative-mass object can't be pulled towards an object (as the first sentence says) and simultaneously repel the object that it is pulled towards. Or can it? 31.210.184.112 (talk) 18:26, 20 July 2011 (UTC)

It can. Negative mass would accelerate in the opposite direction of the force exerted on it. There is no contradiction. --antiXt (talk) 13:19, 30 July 2011 (UTC)

Given two objects with equal and opposite mass subject only to gravity, the system would accelerate from the negative mass towards the positive mass. Total mass, momentum and energy in this system remains a constant 0, despite the increase of velocity without bound. — Preceding unsigned comment added by 150.176.192.118 (talk) 16:08, 23 January 2012 (UTC)

From the article, it's not clear why opposite mass but same charge would repel.

The very last sentence of the article: "This behavior implies that both have positive inertial mass and opposite charges; if the reverse were true, then the particle with positive inertial mass would be repelled from its antiparticle partner." needs, at the very least, a reference. I am making the assumption that "if the reverse were true" means "if both have like-charge but opposite mass". There needs to be a reference or further explanation because after reading the entire article, it's not clear to me why having opposite mass but like-charge would repel as this last sentence to the article states.

My doubt comes from looking at an earlier statement in the article about negative mass and the electrostatic force: "Geoffrey A. Landis pointed out other implications of Forward's analysis,[2] including noting that although negative mass particles would repel each other gravitationally, the electrostatic force would be attractive for like-charges and repulsive for opposite charges." Given that if both particles are positive mass then the electrostatic force is repulsive for like-charges, and that if both particles have negative mass then the electrostatic force is attractive for like-charges, it's not obvious that if one particle has positive mass and the other has negative mass then like-charges would produce a repulsive electrostatic force no different than if both masses were positive.

The symmetry of the situation almost seems to suggest they would not be attracted or repulsed by the electrostatic force because

positive/negative is to positive/positive

as

negative/positive is to negative/negative

So, if positive/positive masses repel like-charges and negative/negative masses attract like-charges, then positive/negative masses would neither attract nor repel like-charges according to this symmetry. The article needs to explain why it is instead expected that the positive/negative masses would actually behave the same as positive/positive masses as far as electromagnetism goes. Or, at least provide a reference. So, the very last sentence of the article: "This behavior implies that both have positive inertial mass and opposite charges; if the reverse were true, then the particle with positive inertial mass would be repelled from its antiparticle partner." needs, at the very least, a reference.

As noted in the first section of this Talk page, there would seem to be less confusing reasons to rule out negative mass for antiparticles. After re-reading the first section of this talk page titled "Clarification", I realize that comment is similar to mine. In that comment, it is concluded that the negative mass particle would chase after the positive mass particle because the positive mass would be repelled by the like-charge while the negative mass would be attracted to the like-charge. So, overall, there's no net attraction or repulsion but the system accelerates towards the positive mass. --Colinkeenan (talk) 05:15, 26 October 2013 (UTC)

Pair of equal positive/negative mass

Cite from the paper: 'Negative masses in general relativity and the Dirac equation - F. Winterberg'

More detailed analysis of the positive-negative mass two body problem first carried out by Bondi, does not lead to a self acceleration.

It rather leads to the finding that the Dirac spinors can be thought of as being composed of positive and negative mass particles, and rather than leading to a self-acceleration, it leads to the “Zitterbewegung,” which for the Dirac particle was discover ed by Schrödinger. It definitely does not lead to an unstable vacuum composed of positive and negative masses as claimed by Cavalleri and Tonni [7].

Replacing supersymmetry by the assumption that the vacuum is made up by an equal number of positive and negative masses, and replacing the Higgs field by the Einsteinian gravitational field of positive masses interacting with likewise negative masses, it can be seen as a model replacing the standard supersymmetric model of elementary particles and cosmology [8, 9]

So, clearly, a body of positive/negative mass (equal in absolute magnitude) would not chase each other and accelerate indefinately.

Robheus (talk) 13:37, 20 June 2014 (UTC)