The local universe may be expanding more slowly than previously thought, a discovery that could relieve a pesky discrepancy ...

A novel theory suggests that the current expansion rate of the universe is not fixed, but was in fact quite different in the ...

Cosmic voids may seem like the emptiest places in the universe, stripped of matter, radiation, and even dark matter. But they’re far from nothing. Even in these vast empty regions, the fundamental ...

Light released by a distant star does not simply wink out after crossing some threshold of space. In a vacuum, photons keep moving indefinitely, and astronomers routinely detect light that has ...

"Cosmic archaeologists" have discovered an iron-deficient second-generation star, which provides evidence of how ancient ...

Observations show the universe appears flat, yet its true size and global shape beyond the observable horizon may remain forever unknown.

There’s endless debate among cosmologists about what really makes up the emptiness of outer space, though many believe that mysterious stuff that we now call dark matter and dark energy represent a ...

The Boötes Void is one of the most mysterious places ever discovered in space. Spanning hundreds of millions of light-years, it contains almost nothing. No galaxies, no stars, and almost no matter at ...