fine structure constant

Not long ago, a new preprint on the fine structure constant got a bunch of press, nicely summed up by the Knight Science Journalism Tracker last week. I meant to say something about this last week, but what with it being the first week of classes and all, I didn't find the time. I still think it's worth writing about, though, so after a reproduction of the key figure, we'll have the usual Q&A-format explanation of why I don't quite trust this result: So what's this all about? The preprint in question is the latest in a series of attempts to measure possible changes in the fine structure…
Via Jennifer Ouellette on Twitter, I ran across a Discovery News story touting a recent arxiv preprint claiming to see variation in the fine-structure constant. It's a basically OK story, but garbles a few details, so I thought it would be worth giving it the ResearchBlogging treatment, in the now-traditional Q&A format. What did they do? The paper looks at some spectral lines in radio emission from a moderately distant galaxy with the poetic name "PKS1413+135." These lines are produced by OH molecules in interstellar gas clouds, and the frequencies they see suggest that there may have…