Study proposes combining continuum mechanics with Einstein field equations

Albert Einstein’s general theory of relativity is a landmark in our understanding of the universe. It gave rise to the notion of a spacetime continuum against which all physical phenomena play out. But over the decades, it has inspired many questions that have yet to be answered: How can Einstein’s equations describe forces other than gravity? And what are the “dark” forms of energy and matter that cause the universe to expand and galaxies to evolve?