From this internet link that is summarized below:http://www.absoluteastronomy.com/encyclopedia/e/ex/exotic_matter.htm [Broken] is a discussion of possible existence of antimatter having negative mass as presented by physicist Robert Forward. Does anyone know the equations of Robert Forward discussed below that could be applied to comingle two asymmetrical mass entities, one having positive mass and the second having negative mass (say an antimatter negative mass A = 2 boson [N-P] cluster with A = 3 positive mass matter fermion cluster [P-N-P] ) ? I ask this question because such a union between matter and antimatter bosons and fermions is predicted by the R. A. Brightsen Nucleon Cluster Model, which can be viewed at this link: http://www.brightsenmodel.phoenixrising-web.net [Broken]. ========= Although no particles are known to have negative mass, physicists (primarily Robert L. Forward) have been able to describe some of the anticipated properties such particles may have. Assuming that all three concepts of mass are equivalent would produce a system where negative masses are attracted to both positive and negative masses, yet positive masses are repelled away from negative masses. For a negative value of mp with positive value of ma, F is negative (repulsive). At first glance it would appear that a negative mass would accelerate away from a positive mass, but because such an object would also possess negative inertial mass it would accelerate in the opposite direction from F. Furthermore, it can be shown that if both masses are of equal but opposite mass, then the combined system of positive and negative particles will accelerate indefinitely without any additional input into the system. This behavior is bizarre, in that it's completely inconsistent with our 'normal universe' common sense expected behavior from working with positive masses, but it is completely mathematically consistent and introduces no apparent contradictions when physics analysis is performed on the behaviors. Naïve first impressions are that this violates conservation of momentum and/or the capacity of a physical system to do work (The principle that the total linear momentum in a closed system is constant and is not affected by processes occurring inside the system), but in fact if the masses are equal in magnitude, one being of positive value and the other negative, then the momentum of the system is zero if they both travel together and accelerate together, no matter what speed: ...and an equivalent equation can be calculated for Ke. Forward also showed that if m(-) and m(+) are not the same magnitude of mass, the equations are still consistent. Some of the behaviors this seems to introduce are really bizarre, such as a comingled positive matter gas and negative matter gas having the positive matter portion increase in temperature without bound. However, the negative matter portion gains negative temperature at the same rate, again balancing out. Forward has proposed a design for spacecraft propulsion using negative mass that requires no energy input and no reaction mass to achieve arbitrarily high acceleration, though of course a major obstacle to the construction of such a spacecraft is the fact that negative mass remains purely hypothetical.