The Earth's magnetic field and oxygen evolved together over 540 million years, according to a major NASA study.

Today’s climate change pales in comparison with what happened as Earth gave birth to its oxygen-containing atmosphere billions of years ago. By analyzing clues contained in rocks, scientists at the ...

A rough outline of oxygen (O2) concentrations in Earth's atmosphere through time are illustrated in this figure. Brown blocks show the estimated range for O2 in terms of its present atmospheric level ...