Physical World

How to detect clandestine nuclear weapons programs

A “policy physicist” explores practical ways to sniff out uranium processing from afar

Has humankind driven Earth into a new epoch?

Our mark on Earth is so profound that some argue it’s time to bid goodbye to the current geological time period — the Holocene — in favor of a new one: the Anthropocene.

Thar she blows: The what, why and where of geysers

Scientists make progress in mapping the hidden force behind the watery eruptions

Searching for life among the stars

Astronomer Lisa Kaltenegger reckons the galaxy could contain as many as 40 billion habitable planets. Here, she speaks about the search for those faraway worlds and signatures of life.

How snowflakes grow

The cold, finicky science of ice crystal formation

Particles get a move on without motors

Nanospheres that react with their surroundings to propel themselves might find applications in drug delivery

Heterostructures get a quantum buildup

A summary of “Quantum-Matter Heterostructures” by H. Boschker and J. Mannhart that appears in the 2017 Annual Review of Condensed Matter Physics