At the beginning of the twentieth century, most scientists assumed a universe with no beginning and no end. This created certain physical paradoxes, such as how the universe managed to remain stable without collapsing upon itself because of the force of gravity, but other alternatives did not seem very attractive. When Einstein developed the theory of general relativity in 1916, he introduced a “fudge factor” to block gravitational implosion and retain the idea of a steady-state universe. He later reportedly called this “the greatest mistake of my life.”
