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Large Scale Structure

Everywhere we point telescopes in the sky, we see galaxies, going back to the earliest moments in history where galaxies could even exist. These galaxies fall into a pattern: the large-scale structure of the universe. This structure is a huge web shaped by gravity, with most galaxies and galaxy clusters lying along the strands.

On even grander scales, what became galaxies and clusters began as froth on huge cosmic sound waves during the era when the universe was a hot cauldron of particles and light. These waves are called “baryon acoustic oscillations”, and they provide us with a way to measure the expansion rate of the universe, including the mysterious acceleration caused by dark energy.