What are you saying?? You don't think it's been proven that a spaceship can orbit the earth? You don't think that was once a theory???
Buddy....you're proving that you just stayed at Holiday Inn last night.
Okay, now you're showing your ignorance of science. No, theories are never proven. There is always the possibility that new data will render the theory moot. However, researchers can have high degrees of confidence in a theory because it has enormous amounts of supporting data and its ability to allow predictions to be made.
Theories are explainations for things. "A spaceship can orbit the earth" is a prediction, not an explaination.