Are you looking for Alexander the Great quotes? Read on and discover the lessons from history's legendary leader, military ...

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

Geology’s Theory of Everything continues successfully to defend its title. ■ Curious about the world? To enjoy our mind-expanding science coverage, sign up to Simply Science, our weekly ...

Fossils and genetics are starting to point to life emerging surprisingly soon after Earth formed, when the planet was ...

From the beginning of time to the origins of life, our "when" special series tackles the timing of crucial events and the ...

The giant-impact hypothesis posits that billions of years ago a Mars-sized body named Theia collided with the early Earth.