Physics

Cosmologists have shown that it’s theoretically possible for a contracting universe to bounce and expand. The new work resuscitates an old idea that directly challenges the Big Bang theory of cosmic origins.

The fusion of quantum computing and machine learning has become a booming research area. Can it possibly live up to its high expectations?

A series of fossil finds suggests that life on Earth started earlier than anyone thought, calling into question a widely held theory of the solar system’s beginnings.

A mysterious object that repeatedly bursts with ultra-powerful radio waves must live in an extreme environment — something like the one around a supermassive black hole.

For decades, physicists have struggled to create a quantum theory of gravity. Now an approach that dates to the 1970s is attracting newfound attention.

A complete classification could lead to a wealth of new materials and technologies. But some exotic phases continue to resist understanding.

The mother of all string theories passes a litmus test that, so far, no other candidate theory of quantum gravity has been able to match.

Updated results from a Japanese neutrino experiment continue to reveal an inconsistency in the way that matter and antimatter behave.

It weighs as much as 780 million suns and helped to cast off the cosmic Dark Ages. But now that astronomers have found the earliest known black hole, they wonder: How could this giant have grown so big, so fast?