Experimental tests of the twin paradox using extraterrestrial clocks*

We know modern physics has two cornerstones: quantum mechanics and the special theory of relativity. Are these two theories consistent with each other? The key question here is that: Is the vacuum between matters empty or not? The principle of relativity (PR) requires the vacuum to be empty; otherwise, the vacuum will become a resting frame in our universe. Then, one can use this resting frame to determine which inertial frame is stationary and which frame is moving. However, the assumption of an empty vacuum is in contradiction with our understanding in quantum mechanics, which regards the vacuum as the ground state of the quantum system. There is plenty of evidence indicating that the vacuum is not empty. Thus, it is very much worthwhile to reinvestigate an old question: Can any inertial frame be regarded as a stationary frame? It had been pointed out long time ago that the PR will cause a twin paradox. In the previous experiments that supported the PR, they only demonstrated that time dilation is real, but did not test whether any inertial systems can be chosen as the stationary frame. To overcome their problems, we propose here to use two identical clocks placed separately on Earth and Mars to test the twin paradox. The details of our experiment design will be presented in this paper.