Equation 10 · Part 1 · From Origins to Frontier: A History of Precision Cosmology
Symbol H_0
What this part means
the reported a local.
Its job in the formula
is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.
Full expression→Symbol H_0→Article meaning
Where the article explains it
The SH0ES team’s 2022 analysis, using Hubble Space Telescope observations of Cepheids in the hosts of forty-two Type Ia supernovae, reported a local of 73.04 ± 1.04 kilometers per second per megaparsec [ 7 ] .
The passage around this formula
The local, late-universe route to does not go through the CMB at all. It is built from a distance ladder: geometric parallax anchors the distance to nearby Cepheid variable stars, Cepheids calibrate the peak luminosity of Type Ia supernovae in the same host galaxies, and those calibrated supernovae are then used to measure distances — and thus the expansion rate — out to galaxies far enough that their recession velocity is dominated by cosmic expansion rather than local motion. The SH0ES team’s 2022 analysis, using Hubble Space Telescope observations of Cepheids in the hosts of forty-two Type Ia supernovae, reported a local of 73.04 ± 1.04 kilometers per second per megaparsec [ 7 ] .
Learn the underlying idea
A subscript is a label attached below a symbol. It often selects a time step, component, category, or member of a sequence.
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Sources cited in the surrounding passage
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