The bizarre absence of certain gene classes in eukaryotes is key to understanding their evolution and complex links with prokaryotes.

A source of astoundingly energetic -rays associated with a star cluster might provide a clue to a century-old question: where do the cosmic rays that constantly bombard Earth come from?

A huge phytoplankton bloom in the Southern Ocean yields estimates of how a continuous supply of iron affects oceanic carbon sequestration. But iron is not the only factor — nutrient supply is crucial too.