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One minor imprecision: The article states "Current models based on data from Gaia and other surveys favor four spiral arms and the presence of a fifth arm or spur, located close to the sun, he said." Actually, with the help of Gaia we now know that what was once thought to be a spur might be an arm in its own right. At the very least it is a long interarm feature. The #GaiaMission is redrawing the portrait of the #MilkyWay!
