Research NewsAstronomy

Closing In on Cosmic Expansion

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Science  24 Nov 1995:
Vol. 270, Issue 5240, pp. 1295-1296
DOI: 10.1126/science.270.5240.1295


The battle over the Hubble constant, the rate at which the universe is expanding, has raged for decades, fueled by the difficulty of measuring cosmic distances. One camp favored an expansion rate that implies an aged universe, the other a rate that implies a universe seemingly younger than the oldest stars. Supernovas may finally be breaking the impasse by giving astronomers a trustworthy “standard candle”—an object whose faintness is a true indicator of distance. They put the cosmos in comfortable middle age.