When Albert Einstein introduced his theory of general relativity in 1915, it changed the way we viewed the universe. His gravitational model showed how Newtonian gravity, which had dominated astronomy and physics for more than three centuries, was merely an approximation of a more subtle and elegant model. When Albert Einstein introduced his theory of general relativity in 1915, it changed the way we viewed the universe. His gravitational model showed how Newtonian gravity, which had dominated astronomy and physics for more than three centuries, was merely an approximation of a more subtle and elegant model. Astronomy Phys.org – latest science and technology news stories