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Astronomy

Quantifying the Baryon Acoustic Oscillation Scale for Dark Energy Constraints

Quick fact

The baryon acoustic oscillation scale is roughly 150 megaparsecs—about 490 million light-years—a distance that has remained essentially unchanged since the universe was a few hundred thousand years old. By measuring how this 'standard ruler' appears at different cosmic epochs, astronomers can directly trace the universe's expansion history and put tight constraints on dark energy.

Why this is interesting

Ever wonder how cosmologists measure the universe's expansion without a giant measuring tape? They use ripples from the Big Bang as a cosmic ruler—but how does that work?