General Relativity has been the accepted version ever since it predicted the change in Mercury's orbit and the deflection of star light seen during a solar eclipse. It predicted these "Einstein Rings" seen in the above image. It's true that General Relativity and Quantum Mechanics don't mesh logically together and the greatest conflict is demonstrated by black holes and dark matter.
This contradiction screams out for some kind of modification and resolving that has been the Holy Grail of Physics for nearly a century. I happen to believe String Theory resolves the issue. Experimental physicists have been searching for years for this so called 'Dark Matter' and have yet to find it
I contend "Dark Matter" is no more real than the ether that supposedly carried light or the Philosophers Stone.
How to explain this unseen matter? Since String theory postulates 10, 11 or even 26 separate dimensions you could literally stack 3 dimensional universes like pages in a book. Gravity is a weak force because it effects the other pages . We are literally seeing the effects of another page next to our universe! That means that weird things like the ever increasing expansion of the universe or virtual particles producing quantum noise are simply the result of these extra dimensions . String theory also has ways of removing division by zero for black holes. It has the added benefit of predicting gravity from it's basic tenants. It's simply too beautiful not to be true as far as I am concerned.