At https://phys.org/print463198725.html … a new study unifies dark matter and dark energy into a single phenomenon, a fluid which they say possesses negative mass. If you were to push a negative mass it would accelerate towards you, we are told. Currently, cosmology does not integrate negative mass into the mainstream model of the universe so this is a distinct departure, it would seem. In addition, the current model of the universe tells us nothing about what dark matter and dark energy are like physically. This is not surprising as they were invented in order to explain distinct anomalies in the model. The study says we only know about them because of gravitational effects they have on observable matter, which sums it up I suppose. Dark matter and dark energy are therefore theoretical explanations – and therefore negative mass as a way of explaining them must also be the same.
The new model is published in Astronomy and Astrophysics (December 2018) and suggests dark matter and dark energy posses a negative gravity repelling anything around them. Later, we are told, Einstein provided the first hint of the dark universe 100 years ago, when he put forward the theory of a cosmological constant. Einstein later said this was a major blunder on his part but it seems modern astrophysicists and cosmologists think it is a real phenomenon. However, proof of the pudding will come from tests performed by radio telescopes. Will the new model fly or sink. We can only assume more will follow.