One of the issues that physics is trying to investigate is whether our physical constants are the same everywhere else in the universe. This just doesn't mean that it could be different in a different location of the universe due to the exotic conditions, but also at different times throughout the evolution of the universe. We have heard about the controversial idea that the fine structure constants could have varied at different times during the life of our universe.
Now comes the latest verification that comes from 6 billion light years away regarding the ratio of the mass of the proton to the mass of the electron. Murphy et al. have reported that, within the limits of their experiment (which is the most accurate so far), they see no variation in this ratio. This means that this constant is the same even back that far in time.
You may read a review of this work here as well.
 M.T. Murphy et al., Science v.320, p.1611 (2008).