I keep seeing references to relativity around me recently. It occurred to me that it’s a word with lots of different meanings, that is relevant to our lives on so many levels. What is relativity, really? It depends how you look at it.
Since the “discovery” of superluminal neutrino travel was announced, relativity has been a talking point in the media: will Einstein’s theories be proved wrong by these findings? It doesn’t look too likely at the moment. To reiterate, the measurement of the super speedy neutrinos is not “fact” – the OPERA experiment team posted their findings in a paper to the Arxiv to solicit ideas, opinions and follow-up experiments to try and explain their baffling observations. Not everyone turned out in favour of this publication strategy, and I use “publication” in the broadest sense and not in its peer-reviewed, journal-accepted kind, but I think it’s an open, responsible, and engaged approach to take when you’ve run out of ideas.
I think it’s likely that these results will be explained in a way that does not require reprinting thousands of textbooks. But in any case it’s good to remind ourselves that no theory, however firmly established, is above scrutiny. And with the Large Hadron Collider in full swing and some interesting developments in gravity research, our fundamental framework for understanding the physics of the Universe, from the Standard Model of particle physics to General Relativity and the Lambda cold dark matter paradigm, is facing some strong challenges.
Every measurement we make is relative to something – a standard. That standard must be known to a much higher precision that the quantity we’re trying to measure. In the end, most of our basic standards, which we adopt as measurement units, are defined in terms of the most fundamental quantities of nature we know – the speed of light, the energy levels within an atom.