The Hubble constant, within cosmological research, denotes the present-day proportionality factor relating the recession velocity of extragalactic objects to their proper distance in the expanding universe, and thus operationally defines the local expansion rate. As a research area, work on the Hubble constant encompasses precision measurement via distance-ladder methods (e.g., Cepheids, Type Ia supernovae), early-universe inferences from cosmic microwave background anisotropies and baryon acoustic oscillations, and associated statistical and systematic error analyses. This field currently focuses on resolving tensions between independent determinations, refining calibration strategies, and constraining cosmological models and new physics through improved estimates of this parameter.
One of the most stubborn issues in cosmology today concerns the universe's rate of expansion. Scientists know it's expanding, but defining the rate of that expansion is challenging. The rate of expansion is called the Hubble ...
Astronomy
Jan 19, 2026
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There is an important and unresolved tension in cosmology regarding the rate at which the universe is expanding, and resolving this could reveal new physics. Astronomers constantly seek new ways to measure this expansion ...
Astronomy
Dec 5, 2025
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Last time I wrote about new data that overturns the standard cosmological model. Before anyone starts dusting off their fringe cosmological models, we should note what this new study doesn't overturn. It doesn't say the Big ...
Astronomy
Nov 15, 2025
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For the first time, an international research team led by the Shanghai Astronomical Observatory (SHAO) of the Chinese Academy of Sciences has demonstrated that applying pixelized strong-lensing modeling on a galaxy cluster ...
Astronomy
Nov 3, 2025
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For the past decade, scientists have been trying to get to the bottom of what seemed like a major inconsistency in the universe. The universe expands over time, but how fast it's expanding has seemed to differ depending on ...
Astronomy
May 27, 2025
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A new study in Monthly Notices of the Royal Astronomical Society by researchers including István Szapudi of the University of Hawaiʻi at Mānoa Institute for Astronomy suggests the universe may rotate—just extremely slowly. ...
Astronomy
Apr 14, 2025
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Researchers from the University of Waterloo have proposed a new method to measure the Hubble constant that could help resolve one of modern cosmology's pressing puzzles: the Hubble tension.
The universe really seems to be expanding fast. Too fast, even. A new measurement confirms what previous—and highly debated—results had shown: The universe is expanding faster than predicted by theoretical models, and faster ...
Astronomy
Jan 17, 2025
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New observations from the James Webb Space Telescope suggest that a new feature in the universe—not a flaw in telescope measurements—may be behind the decade-long mystery of why the universe is expanding faster today than ...
Astronomy
Dec 9, 2024
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Astronomers have known for a century that the universe is expanding. We can now trace this expansion over much of its almost 14 billion year history, with important constraints going back to just one second after the Big ...
