If I may...

You can't "prove" a theory about nature.
All you can do is test it. If it survives enough tests, you start to get convinced that it's probably true. But this is just common sense, not proof.
Newton's physics was "true" all though the 19th century, and then all of a sudden everything changed. Of course it had never really been proven to be true; it had just been *put to the test* a large number of times, and passed.
Then, one fine day, it didn't pass the test.
Maybe one day that will happen to Einstein's Relativity Theory too. It's always possible.