# Archive

## Latest Articles

### Is Perpetual Motion Possible at the Quantum Level?

A new phase of matter called a “time crystal” plays with our expectations of thermodynamics. The physicist Vedika Khemani talks with Steven Strogatz about its surprising quantum behavior.

### The Most Important Machine That Was Never Built

When he invented Turing machines in 1936, Alan Turing also invented modern computing.

### A Very Big Small Leap Forward in Graph Theory

Four mathematicians have found a new upper limit to the “Ramsey number,” a crucial property describing unavoidable structure in graphs.

### How a Human Smell Receptor Works Is Finally Revealed

After decades of frustration, researchers have determined how an airborne scent molecule links to a human smell receptor.

### The Computer Scientist Peering Inside AI’s Black Boxes

Cynthia Rudin wants machine learning models, responsible for increasingly important decisions, to show their work.

### Why Mathematicians Re-Prove What They Already Know

It’s been known for thousands of years that the primes go on forever, but new proofs give fresh insights into how theorems depend on one another.

### How Pools of Genetic Diversity Affect a Species’ Fate

A new, deeper understanding of how the breeding structure of species affects their genetic diversity is giving conservationists better tools for saving animals.

### Tiny Jets on the Sun Power the Colossal Solar Wind

A new analysis argues that ubiquitous eruptions in the sun’s corona explain the vast flow of charged particles seen streaming out through the solar system.

### The Number 15 Describes the Secret Limit of an Infinite Grid

The “packing coloring” problem asks how many numbers are needed to fill an infinite grid so that identical numbers never get too close to one another. A new computer-assisted proof finds a surprisingly straightforward answer.