• Question: What is the fine constant structure and why is it nearly 1/137

    Asked by byronlogan12345 to Claire, Kate, Matt, Rob, Sam on 20 Jun 2013.
    • Photo: Robert Woolfson

      Robert Woolfson answered on 20 Jun 2013:

      The fine structure constant measures how strongly light and electrons interact. It controls how strong chemical bonds are, how we see light and the vast majority of the things in the world that we see. It also controls fusion in stars, which is important as that’s how all the chemical elements are created.

      Why it’s 1/137? A very famous physicist called Max Born said this once –

      “If alpha [the fine-structure constant] were bigger than it really is, we should not be able to distinguish matter from ether [the vacuum, nothingness], and our task to disentangle the natural laws would be hopelessly difficult. The fact however that alpha has just its value 1/137 is certainly no chance but itself a law of nature. It is clear that the explanation of this number must be the central problem of natural philosophy.”

      He was a genius and he had no idea. People have argued for decades but the honest answer is we don’t know.

    • Photo: Sam Geen

      Sam Geen answered on 21 Jun 2013:

      There’s something called the Anthropic Principle, which says that the universe is the way it is because if it wasn’t then we wouldn’t be around to see it – if the fine structure constant was different, atoms wouldn’t work in the same way and so that, perhaps, stars couldn’t burn, or life couldn’t happen, and there’d be no people. Perhaps there are other universes with different values that we don’t live in. But I appreciate that this isn’t very satisfying answer, and like Rob says, ultimately we don’t know why our universe has this value.

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