A newly developed technique could one day help astronomers use giant sound waves to test theories of dark energy, the mysterious force thought to be causing the universe to fly apart faster over time.
Called intensity mapping, the technique looks for unique radio emissions of hydrogen gas in galaxies and galaxy clusters to map the large-scale structure of the universe. Hydrogen is the lightest and most abundant element in the universe, and it tends to cluster around galaxies because of their strong gravitational pull.
Until now, astronomers have been mapping large cosmic structures by identifying the galaxies and clusters themselves—a process akin to mapping forests on Earth by counting individual trees. The new method is more like mapping forests by looking for large patches of green.
By speeding up large-scale mapping efforts, the method should reveal how structures in the universe have evolved since the big bang.
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