Only a small fraction of the observable universe is comprised of visible matter. Current data suggests all galaxies are ...

Dark energy is the mysterious force thought to be accelerating the universe. . But a new study hints that scientists may have ...

A new study questions dark energy's role in the universe's acceleration, suggesting it may be weakening instead.

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

Rogue planets — worlds that drift through space alone without a star — largely remain a mystery to scientists. Now, ...