Before plants ruled, Earth may have glowed violet. The first life forms used retinal instead of chlorophyll, absorbing green light and reflecting red and blue—turning the planet an eerie purple.

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.

For a long stretch of Earth’s history, our planet might have looked green from a distance, instead of the pale blue dot we know today. Earth’s green period, which lasted from around 3 billion ...

Enjoy Earth Day with a glass of refreshing celery ... With its tender stem and vibrant green color, this versatile veggie is a must-try. Get the Roasted Frozen Asparagus recipe.