Dark energy may be the most mysterious substance ever proposed, but many scientists are certain it exists. Why?

For a quarter century, cosmology has rested on a simple but audacious idea: that a fixed “cosmological constant” drives the ...

Our universe is shrouded in mystery, with about 70 percent of it consisting of dark energy. The exact nature of dark energy remains a puzzle that, once solved, could unlock profound insights into the ...

Learn how Hubble is measuring the expansion rate of the Universe in this new explainer from NASA's Goddard Space Flight ...

New hints from one of the most extensive surveys of the cosmos to date suggest that mysterious dark energy may be evolving in ways that could shift how astronomers understand the universe. Dark energy ...

Last year, we reported on an exciting hint of new physics in the first data analysis results from the Dark Energy Spectroscopic Instrument (DESI)—namely that the dark energy, rather than being ...

For decades, astronomers have believed that dark matter and dark energy make up most of the universe. However, a new study suggests they might not exist at all. Instead, what we perceive as dark ...

For a quarter century, cosmology has leaned on one framework to explain how the universe expands. Known as the ΛCDM model, it assumes about 70 percent of the cosmos is filled with an unseen force ...

“Dark energy” is a term scientists use to refer to whatever is causing the universe to expand faster over time. We don’t know exactly what dark energy is—no one has ever directly seen or measured ...

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