Time passes faster in Munich than in Braunschweig - at least physically this is a fact according to Einstein's general theory of relativity. The difference has to do with the fact that Munich is geographically at a higher altitude, and although the difference is tiny at around one second in a million years, it can be measured very precisely using optical atomic clocks. Such chronometric altitude measurements have revolutionary potential for measuring and observing the Earth. Researchers from the Physikalisch-Technische Bundesanstalt (PTB), Leibniz University Hannover (LUH) and the Max Planck Institute of Quantum Optics (MPQ) have now measured the difference in altitude between Munich and Braunschweig using two optical clocks. Their scientific article resulted from the Cluster of Excellence QuantumFrontiers and the Collaborative Research Centre TerraQ and has now been published in the current issue of the journal Physical Review Applied.
