Billions of years ago, our planet did not have the deep blue oceans we admire today. Instead, they were actually […] ...

Although the Earth’s been decidedly blue for 600 million years, rising populations of phytoplankton caused by rising temperatures are once again causing the world’s oceans to turn green.

A distinctive blue and green image of Earth reveals our planet's most remarkable features. At 4.54 billion years old, our home world is a venerable object. But it was only with the arrival of the ...