Observations of the way light scatters from large astrophysical bodies provides independent confirmation of the standard model of cosmology.
The cosmic microwave background (CMB)—relic photons from the early stages of the universe—is well established as a precise probe of cosmology, providing a clear picture of the universe when it was
1/1000
th its current size. A new generation of experiments now makes it possible to also use the CMB to probe large-scale structure, like galaxies and galaxy clusters, in those parts of the universe that are relatively close by. In Physical Review Letters [1], an international team of researchers (Hand et al.) reports they have been able to detect the tendency of large clumps of matter to move toward each other using CMB data collected by the Atacama Cosmology Telescope (ACT) and a large galaxy catalog compiled by the Baryon Oscillation Spectroscopic Survey (BOSS), an experiment designed to detect the imprint of early universe sound waves in the local galaxy distribution. Measurements like these provide new tests of gravity on large scales as well as a different perspective on dark energy, the strange form of energy density that appears to be driving the accelerating expansion of the universe.
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