There are many levels at which a scientific question can be answered. An answer that is quite satisfying to a scientist from one discipline may be totally unsatisfactory to a scientist from another.

Astronomers can finally breathe a sigh of relief: A team of scientists has discovered the first oxygen molecules in deep space, capping a nearly 230-year search for the elusive cosmic molecule. The ...

A turning point in the history of life occurred 2 to 3 billion years ago with the unprecedented appearance and dramatic rise of molecular oxygen. Now researchers report they have identified an enzyme ...