But there are some holes in Einstein’s theory, including some gravitational weirdness around low acceleration “wide binary” stars. However, if these accelerations were above 10 nanometers per second squared, they followed the Newton-Einstein theory as predicted. In the standard model of gravity, this is where concepts of dark matter become vitally important. Similar to how the Newton-Einstein theory relies on the ever-elusive particle known as dark matter, MOND contains its own limitations and challenges. Chae’s study appears to be a big +1 in the pro column for Modified Newtonian Dynamics, but the theory is still just that—a theory.