This is the alpha constant, a pure number which determines the structure of atoms in our universe. Had it been more than 4% different it would be impossible to have stable carbon atoms, and therefore there would not be carbon-based life-forms writing blogs and pondering about the mystery of this number.

To get the alpha constant you must multiply the square of the electron charge by 2 pi and then divide the product by the product of the speed of light times the Planck constant. So it is a constant of constants, with the difference that is dimensionless, i.e. id does not have measurement units. If an alien civilization used any other different set of measurement units to describe the same physical constants they would arrive at the same, pure, number.

So why this number? Why this universe so fine-tuned for life? During the long debate about the alpha constant some of the most logical, and at the same time crazy, hypotheses, were (a) that there are infinite number of universes and we just happen to inhabit in the life-friendly one – the “multiple universes hypotheses” and (b) that we inhabit a small part of a much, much, much bigger universe where all kinds of variations of nature’s constants occur – “the multiverse hypothesis”.

In a paper just submitted to Physical Review Letters, a team led by John Webb and Julian King from the University of New South Wales in

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