Fact Sheet
Sounding Out Dark Energy
One way in which astronomers will search for mysterious dark energy is to seek the "imprint" of sound waves from the very early universe. Among several efforts to find this imprint, known as baryon acoustic oscillations, is HETDEX at McDonald Observatory. This diagram shows the basic concept. Top: A field of galaxies for study. Center: Astronomers will measure the distances between millions of galaxy pairs, and use statistics to find a common "scale length." Bottom: This common length is the imprint of the early sound waves, which shows up as "ripples" in the distribution of galaxies. The scale length changes as the universe ages, so determining that length at different epochs will reveal how the expansion rate of the universe has changed over time. [Tim Jones/Damond Benningfield]
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