This column first ran in The Tablet in November 2011 “We don’t serve sub-atomic particles like you here!” growls the bartender. A neutrino walks into a bar.  At the speed of the internet, jokes like that were making the rounds within hours after the announcement [in 2011] that energetic neutrinos produced at CERN in Switzerland were arriving at a detector in Italy, 730 kilometers away, about 60 nanoseconds sooner than they could have arrived even if they had been traveling at the speed of light. The point of the joke has its basis in Einstein’s theory of Relativity. What we measure when we observe the fundamental units of nature, distance and time and mass, depends on the relative velocities of the observer and the thing being observed. Events that in one frame of reference seem to be occurring simultaneously, can appear to an observer moving at a different relative velocity to be happening at different times. The absolute limit, that … Continue reading →