> A measurement of the difference between distinct absorption lines (with different sensitivity to the fine structure constant) from a star leads to a direct es

> A measurement of the difference between distinct absorption lines (with different sensitivity to the fine structure constant) from a star leads to a direct estimate of a variation of the fine structure constant between the star’s location and Earth. Using spectroscopic measurements of 5 stars, we obtain a constraint on the relative variation of the fine structure constant below 10^−5. https://escholarship.org/uc/item/5185m01m https://escholarship.org/uc/item/5185m01m