The expanding universe research area investigates the observational and theoretical foundations of cosmic expansion, originating from general relativity and supported by redshift–distance relations, cosmic microwave background anisotropies, and large-scale structure surveys. It encompasses measurements of the Hubble parameter and its evolution, constraints on dark energy and matter content via cosmological parameters, and tests of the ΛCDM model and its alternatives. Research integrates numerical simulations, precision cosmology, and data from supernovae, baryon acoustic oscillations, and gravitational lensing to characterize the expansion history, probe deviations from general relativity, and refine models of early- and late-time cosmic dynamics.
As the Dark Energy Survey (DES) releases its final results, we caught up with two physicists who've been involved in the project from its early days. In this Q&A, Josh Frieman, DES co-founder and associate laboratory director ...
Astronomy
Jan 26, 2026
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Dark energy is still one of the greatest cosmic mysteries. For all the time, money and telescopes that humanity has used to uncover its nature, scientists are still asking a fundamental question: What is dark energy?
Astronomy
Jan 26, 2026
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The Dark Energy Survey Collaboration collected information on hundreds of millions of galaxies across the universe using the U.S. Department of Energy-fabricated Dark Energy Camera, mounted on the U.S. National Science Foundation ...
Astronomy
Jan 22, 2026
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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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Our universe is filled with galaxies, in all directions as far as our instruments can see. Some researchers estimate that there are as many as 2 trillion galaxies in the observable universe. At first glance, these galaxies ...
Astronomy
Dec 15, 2025
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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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An expanding universe complicates this picture just a little bit, because the universe absolutely refuses to be straightforward. Objects are still emitting light, and that light takes time to travel from them over to here, ...
Astronomy
Nov 24, 2025
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The surface of Earth is finite. We can measure it. If it was expanding, then its size would grow with time. And once again, good ol' Earth helps us understand what the universe might be doing beyond our observable horizon.
Astronomy
Nov 24, 2025
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Over the course of billions of years, the universe has steadily been evolving. Thanks to the expansion of the universe, we are able to "see" back in time to watch that evolution, almost from the beginning. But every once ...
Astronomy
Nov 20, 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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