I agree that e=mc2 has been proven, I do not believe “c” should be read as a velocity as opposed to the transformation that is described which is actually an acceleration. So the real problem is now taking that to the cosmic level of E=Mc2 that implies there was just one transformation of all Energy to Mass at the Big Bang. e=mc2 is a transformation that is going on in both ways all across the universe. Stars are created and black holes are converting mass back to energy.
Over the last few years I have been doing my own research and I believe a fundamental error occurred when Einstein’s e=mc2 was accepted as the gospel truth. I have short paper that describes an error created by allowing a Lorentz Transformation to have a zero value throughout the entire transformation. This in effect creates an optical illusion of something moving backwards. I believe the transformation of matter to energy would be time based making c not a velocity but an acceleration. But if we go back and read about Minkowski world lines, for each world line all rules of physics apply. But I content that each world line can be independent of another. For me if we can only observe light based on our interpretation of its speed there should be nothing stopping mass from that big bang that is moving away from us to be further away than light could travel over the existence of the universe. It doesn’t have to be “Dark” within our observable constraints. It can be normal Standard model stuff but to far away to observe. With an ever-expanding Universe plus the fact that new stars and galaxies are continuously being formed to me it only makes sense there must be some part of the Universe we can not observe.