Astronomy Today

Measuring Units

How did astronomers use Type Ia supernovae to measure the universe?

In the late twentieth and early twenty-first centuries, astronomers from two large research groups measured the luminosities of a large number of Type Ia supernovae billions of light-years away from Earth. By comparing their distances as indicated by their cosmological redshift with those indicated by their standard candle properties, both groups were amazed to discover the same result: The expansion rate of the universe has been slowly but surely accelerating for billions of years. This remarkable result helped to solidify the measurements of the age, geometry, and eventual fate of the cosmos. For their work using Type Ia supernovae, astronomers Saul Perlmutter (1959–), Adam Riess (1969–), and Brian Schmidt (1967–) were awarded the 2011 Nobel Prize in Physics.


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