Science is a process that never sits still. Unlike something like religion, which tends to deal in doctrine and more absolute or unbendable ideas and rules, scientific theories and models and ideas must change if contradictory observations and experimental evidence are discovered. And sometimes new ideas emerge that are just different, and look at problems with a different lens.
This is the case with some new ideas proposed by theoretical astrophysicist Lucas Lombriser from Vienna. He has been thinking about the expansion of the universe, and the measurements that suggest the expansion rate of the universe is actually accelerating - to explain this, astronomers have been suggesting things like 'dark energy' to explain that acceleration, despite having no idea what dark energy actually is. Lombriser proposes there is not even a need for an expanding universe, which goes against the thinking in the field for the past century. Something like this is exciting, and keeps science alive and moving forward. His idea is that an expanding universe is basically an illusion, caused by the time evolution of the mass of particles (like protons and electrons), which is also a new idea. But according to Lombriser's mathematical model, if particle mass is not constant, then the consequence is gravity changes, and things like the expansion of the universe, dark energy, and perhaps dark matter, are not even necessary!
There is no experimental test, yet, for any of these ideas, so we must all consider them but not run too fast with them. I suspect many researchers over the coming decade will be thinking about all this and trying to find any sort of observational or experimental clues that support or deny any pieces of this new model. This is how science is supposed to work. We must be patient and see what Nature is trying to hint to us! If correct, though, WOW! This would make for a paradigm shift in astronomy, and I am sure many other theories and observations would need to be questioned and viewed through this new lens. I love science and this wonderful, and sometimes frustrating, process!