AN ADULT HUMAN body consists of some 37trn cells. Not so long ago, these were thought to come in 220 different types. That number, the product of painstaking decades spent peering through microscopes ...

Researchers identified some 3,300 types of brain cells, an order of magnitude more than was previously known, and have only a dim notion of what most of them do. By Carl Zimmer An international team ...

Precipitation comes in all forms: rain, sleet, freezing rain, and snow. Some even count virga, which becomes a gas and evaporates before it reaches us as raindrops. Hail also exists but forms ...