Debate accelerates on universe’s expansion speed
Discrepancy between different ways of measuring Hubble constant refuses to fade

UNRULY UNIVERSE Different methods for measuring the universe’s expansion rate disagree. To make one such measurement, scientists observed Cepheid variable stars and a type 1a supernova in the spiral galaxy UGC 9391 (shown), located 130 million light-years away in the constellation Draco.
NASA, ESA, L. Frattare/STScI
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