Hubble constant


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Hubble constant

n
(Astronomy) the rate at which the expansion velocity of the universe depends on distance away. It is currently estimated to lie in the range 60–80 km s–1 megaparsec–1. Also called: Hubble parameter
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.Hubble constant - (cosmology) the ratio of the speed of recession of a galaxy (due to the expansion of the universe) to its distance from the observer; the Hubble constant is not actually a constant, but is regarded as measuring the expansion rate today
cosmogeny, cosmogony, cosmology - the branch of astrophysics that studies the origin and evolution and structure of the universe
constant - a number representing a quantity assumed to have a fixed value in a specified mathematical context; "the velocity of light is a constant"
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Astronomers use those values, along with other measurements of the galaxies' light that reddens as it passes through a stretching universe, to calculate how fast the cosmos expands with time, a value known as the Hubble constant. Riess and his SH0ES (Supernovae H0 for the Equation of State) team have been on a quest since 2005 to refine those distance measurements with Hubble and fine-tune the Hubble constant.
At issue is a number called the Hubble constant, a calculation for how fast the universe is expanding.
With this new data, Riess and the team were able to strengthen the foundation of the cosmic distance ladder, which is used to determine distances within the Universe, and calculate the Hubble constant, a value of how fast the cosmos expands over time.
These measurements help with calculating the Hubble constant, the expansion rate of the universe over time, as well as strengthening the cosmic distance ladder, which can determine distance in the universe.
Due to several further specifications, first by Baade (1952) and thereafter by Sandage (1954, 1958), based on an essentially more detailed and larger set of observational data, the rescaled value of the Hubble parameter at the present era, named the Hubble constant, gave for the age of the universe about 13.6 Gyr.
The enhanced capabilities afforded by ALIGO+ are expected to illuminate the origins and evolution of stellar-mass black holes, allow precision tests of extreme gravity, enable detailed study of the equation of state of neutron stars, and permit new tests of cosmology, including fully independent constraints on the Hubble constant.
Lemaitre was also the first to derive what is now known as 'Hubble's law' and also derived the first estimation of what is now called the 'Hubble constant'.
* The Hubble constant is defined currently within H = 55 / 75 km/ (s Megaparsec).
Combining the DES weak-lensing results with other data yields an independently measured value for the current expansion rate of the universe, known as the Hubble constant (see page 20).
And then there is another big question for the astronomers to answer: What is the exact figure of the Hubble constant, which describes the speed in which the universe expands?
"My favourite thing is that we confirmed that colliding neutron stars power short gamma-ray bursts, solving one of the greatest mysteries in present day highenergy astrophysics." One consequence of the detection was that it enabled scientists to use gravitational waves to measure the expansion rate of the universe, known as the "Hubble constant".