If there is one thing our readers like it’s a good story about fundamental constants – and the fine structure constant (α) is always a favourite.
In case you are not familiar with α, it’s a dimensionless quantity (about 1/137) that measures the strength of the electromagnetic interaction. As such, it quantifies how electrons bind within atoms and molecules and therefore can be measured to great precision using spectroscopic techniques. And because atoms can be found just about anywhere between here and the edge of the universe, it’s possible to ask whether α is the same everywhere.
In a paper published this week in Physical Review Letters, an international team of physicists have measured α in the atmosphere of a white-dwarf star – where the gravitational potential is about 30,000 times greater than here on Earth.
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