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

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

A thin shell of air wraps around Earth, stretching about 20 miles above the surface. This invisible veil is packed with tiny molecules that sustain life. Just beyond this fragile layer lies the ...

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

Gravity is by far the weakest of nature’s four fundamental forces, and physicists have spent decades asking a deceptively simple question: why? One answer, first sketched a century ago and refined ...

Despite significant scientific advancement over the last decades, the universe still finds new ways to surprise us. Every ...

We all need some space sometimes—but it's harder to find than you might think. How far into our universe do we have to go to reach somewhere truly empty? Our first stop is the International Space ...

New 3D map of the early universe from HETDEX reveals faint hydrogen light linking galaxies 9 to 11 billion years ago.