Important discoveries in science are confirmed by labs working independently. If you understand the physical laws that govern a process, you should be able to make accurate predictions. The better you understand the laws, the more accurate the predictions should be. For example, the laws of planetary motion are fairly well understood, and scientists can pinpoint the location of planets hundreds of years into the future. A hypothesis must be testable .
Scientists tend to shy away from statements of absolute proof.
Instead they speak of probabilities or most likely explanations.