Purple Earth Hypothesis suggests Earth was once a purple planet. Early microbes used retinal, not chlorophyll, for ...

Here are some ways to add them to your diet: Purple foods, such as vegetables, fruits, and some grains, range in color from bright purple to deep, almost black hues. Their color comes from ...

Traditionally, paved roads and pedestrian walkways have been illuminated by streetlights emitting a bright white, orange, or yellow glow. The aim is visibility, not aesthetics, and rarely will ...