Year in Review: Planck refines cosmic history

Satellite hints at slower expansion rate for universe

CHANGING TEMPS  A color-coded map shows fluctuations in microwave radiation temperature across the sky recorded by the Planck satellite. Noteworthy features include differences between hemispheres and a cold spot (circle at right).

ESA and the Planck Collaboration 

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In October, astronomers said good-bye to the European Space Agency’s Planck satellite, breaking off contact with the source of the most precise measurements yet of the universe’s oldest light.