the abrahamâminkowski controversy is a physics debate concerning electromagnetic momentum within dielectric media. related theories have been put forward that, should their principles be proven, may allow the design of a reactionless drive. ==theoretical basis== two equations exist describing momentum transfer between matter and electromagnetic fields.  erratum:  both seem to be supported by contradicting experimental data. the two existing equations were first suggested by hermann minkowski (1908)  :*wikisource translation: the fundamental equations for electromagnetic processes in moving bodies and max abraham (1909), :*wikisource translation: on the electrodynamics of moving bodies  :*wikisource translation: on the electrodynamics of minkowski from which the controversy name derives. both define the momentum of an electromagnetic field permeating matter. abraham's equation suggests that in materials through which light travels more slowly, electromagnetic fields should have lower momentum, while minkowski suggests it should have a greater momentum. "using relativity, feigel found that the abraham definition accounts for the momentum of the electric and magnetic fields alone, while the minkowski definition also takes into account the momentum of the material". {{cite journal |last=cho |first=a. |year=2004 |url=htt
Electric_and_magnetic_fields_in_matter Scientific_controversies