Objects In Mirror Are Bluer Than They Appear: What a Galaxy's Color Says About Its Distance

Feb 3, 2022
Understanding how the Universe evolved from a dense ball of superheated plasma to the vast canvas of stars and galaxies it is today—and what it will become next—remains a fundamental question asked throughout history. Today, we can begin to answer this question by making more precise measurements of objects in space, from our nearest neighbors to the deepest recesses of the visible Universe, than we've ever been able to before. The resulting maps help us frame the question of how the Universe unfolds by measuring how cosmic structure—the web of galaxies that make up the Universe—grows over time, according to the rules of physics. A key part of measuring this cosmic structure is to determine the distances to the many galaxies we observe with our telescopes.