mega·​par·​sec | \ ˌme-gə-ˈpär-ˌsek How to pronounce megaparsec (audio) \

Definition of megaparsec

: a unit of measure for distances in intergalactic space equal to one million parsecs

Examples of megaparsec in a Sentence

Recent Examples on the Web The trend continued; as of their latest analysis last March, Riess’s team pegged the Hubble constant at 74 kilometers per second per megaparsec, 9% higher than the 67.4 extrapolated from the early universe. Quanta Magazine, "New Wrinkle Added to Cosmology’s Hubble Crisis," 26 Feb. 2020 Under certain assumptions about the fundamental nature of the universe, Planck data suggest that the Hubble constant should have a value of 67.4 kilometers a second per megaparsec, give or take 0.5. Michael Greshko, National Geographic, "The universe might be acting weird. Cosmic 'lenses' may help reveal why.," 12 Sep. 2019 The Planck team predicts that the universe should expand at a rate of 67.4 kilometers per second per megaparsec. Quanta Magazine, "Cosmologists Debate How Fast the Universe Is Expanding," 8 Aug. 2019 These ripples can be mapped and modeled to predict the expansion rate, which placed it at 67.4 kilometers per second per megaparsec. Ashley Strickland, CNN, "Red giant stars create new way to measure how quickly the universe is expanding," 16 July 2019 Planck's data pegs the Hubble constant at about 67.4 kilometers per second per megaparsec, give or take 0.5. National Geographic, "The universe seems to be expanding faster than all expectations," 25 Apr. 2019 According to the cosmic ladder, the universe is expanding at a rate of 73.24km per second per megaparsec. The Economist, "The two ways to measure how fast the universe is growing do not agree," 17 May 2018 According to supernovae and Cepheids, the universe is expanding at a rate of 73.5 kilometers per second per megaparsec (about 3.3 million light-years). Lee Billings, Scientific American, "Cosmic Conflict: Diverging Data on Universe’s Expansion Polarizes Scientists," 16 May 2018 From the first neutron-star collision alone, Holz and hundreds of coauthors calculated the Hubble constant to be 70 kilometers per second per megaparsec, give or take 10. Quanta Magazine, "Colliding Neutron Stars Could Settle the Biggest Debate in Cosmology," 25 Oct. 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'megaparsec.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of megaparsec

1920, in the meaning defined above

History and Etymology for megaparsec

mega- + parsec

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The first known use of megaparsec was in 1920

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Cite this Entry

“Megaparsec.” Dictionary, Merriam-Webster, Accessed 21 Apr. 2021.

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